Textile and Paper Chemistry and Technology

Textile and Paper Chemistry and Technology Jett C . A r t h u r , Jr.,

EDITOR

Southern Regional Research Center, USDA

A symposium sponsored by the Cellulose, Paper and Textile Division at the 171st Meeting of the American Chemical Society New York, N.Y., April 5-9, 1976

ACS

SYMPOSIUM

SERIES

AMERICAN CHEMICAL SOCIETY 1977 WASHINGTON, D. C.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

49

L i b r a r y o f Congress

Data

Textile and paper chemistry and technology. (ACS symposium series; 49 ISSN 0097-6156) Includes bibliographical references and index. 1. Paper making and trade—Congresses. 2. Textile industry—Congresses. I. Arthur, Jett C. II. American Chemical Society. Cellulose, Paper, and Textile Division. III. Series: American Chemical Society. ACS symposium series; 49. TS1080.T43 ISBN 0-8412-0377-6

677'.0283 ACSMC8

77-7938 49 1-304

Copyright © 1977 American Chemical Society All Rights Reserved. N o part of this book may be reproduced or transmitted in any form or by any means—graphic, electronic, including photocopying, recording, taping, or information storage and retrieval systems—without written permission from the American Chemical Society. PRINTED IN THE UNITED STATES OF AMERICA

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

ACS Symposium Series Robert

F.

Gould,

Editor

Advisory Donald G . Crosby Jeremiah P. Freeman E. Desmond Goddard Robert A . Hofstader John L. Margrave Nina I. McClelland John B. Pfeiffer Joseph V . Rodricks Alan C. Sartorelli Raymond B. Seymour Roy L. Whistler Aaron Wold

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

FOREWORD The ACS S Y M P O S I U a medium for publishing symposia quickly in book form. The format of the S E R I E S parallels that of the continuing A D V A N C E S I N C H E M I S T R Y S E R I E S except that in order to save time the papers are not typeset but are reproduced as they are submitted by the authors in camera-ready form. As a further means of saving time, the papers are not edited or reviewed except by the symposium chairman, who becomes editor of the book. Papers published in the ACS S Y M P O S I U M S E R I E S are original contributions not published elsewhere in whole or major part and include reports of research as well as reviews since symposia may embrace both types of presentation.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

PREFACE he Centennial Meeting of the American Chemical Society gave the Cellulose, Paper and Textile Division the opportunity to hold a timely symposium on International Developments in Cellulose, Paper, and Textiles. Research scientists from academia, industry, and government, representing more than sixteen countries, presented significant research accomplishments in paper, wood, and cellulose chemistry and in cotton, wool, and textile fiber chemistry. In this volume, researc and technology are discusse ing, pulp and paper, and energy and environment. Two additional vol­ umes, "Cellulose Chemistry and Technology" and "Cellulose and Fiber Science Developments: A World View," will include other contributed manuscripts. I would like to thank the participants, presiding chairmen, and par­ ticularly P. Albersheim, D . F. Durso, C. T. Handy, B. Leopold, A. Sarko, L. Segal, and A. M . Sookne whose leadership made the twenty-two ses­ sions of the symposium truly international in scope. Herman Mark kindly made significant remarks to open the Symposium. Α

Southern Regional Research Center, USDA New Orleans, La. March 14, 1977

JETT

C. ARTHUR, JR.

vii

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

1 N e w Methods for Studying Particles in Viscose and Their Effects on Viscose Rayon Production JOHN DYER ITT Rayonier Inc., ERD, Whippany, NJ FREDERICK R. SMITH Avtex Fibers Inc., Front Royal, VA Cellulose is made outlined in Table I. I aqueous sodium hydroxide to convert the cellulose to the more reactive sodium celluloseate. After steeping, the pulp is pressed to remove excess steeping liquor and then shredded into alkali cellulose crumbs. The crumbs are aged to reduce the cellulose DP before reacting with carbon disulfide to form sodium cellulose xanthate. The derivative is dissolved in dilute aqueous sodium hydroxide, yielding a viscous orange colored solution called viscose. The viscose is aged, during which time air is removed, and chemical and physical changes occur. Then, the solution is f i l tered before extruding through very small holes of a jet into an acid spin bath. There regeneration of the cellulose as filaments of rayon occurs. A normal jet for regular staple manufacture can contain more than 20,000 holes. Typical hole sizes are 1-3.5 mil or 25-90 microns. Particles or other discontinuities, even having size appreciably less than a jet hole, will interfere with viscose flow through the hole, changing the flow from laminar to plug over an area equal to the profile the particle presents to the hole. It is well established that many particles exist in viscose solutions. These originate from the raw materials used in the process - the pulp, caustic and water and from contaminants introduced with the raw materials or from line deposits. The normal practice to avoid interruption in fiber formation at the jet is to remove the particles by filtration. But it has been conclusively shown in several independent studies (1,2)that viscose cannot be completely freed of particles, even with repeated filtration. Rather, there is a distribution of particle sizes meeting some critical parameters of the filter media, filtration pressure and particle nature that will pass through the filters and reach the jet. The potential problems these particles can cause are jet hole plugging, either completely or partially, leading to high spinning 3

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

4

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

pressure and denier non-uniformity. I f the p a r t i c l e s pass through the j e t h o l e s , and most do, they would be expected to i n f l u e n c e f i b e r s t r u c t u r e formation. Adverse e f f e c t s of v i s ­ cose p a r t i c l e s on f i b e r p r o p e r t i e s have been documented i n work by P h i l i p p , S c h l e i c h e r and Arnold (3) and by Zubakhina.j Serkov and Virezub ( 4 ) . Based on p a r t i c l e count measurements by conductometrie, microscopy and l i g h t s c a t t e r i n g methods, T r i e b e r (5) has sug­ gested a s i z e d i s t r i b u t i o n f o r v i s c o s e p a r t i c l e s which begins with molecules of c e l l u l o s e xanthate and extends to masses l a r g e r than 30 microns diameter. The m a j o r i t y of p a r t i c l e count s t u d i e s on v i s c o s e have been made by measuring the change i n c o n d u c t i v i t y as the p a r t i c l e s flow between e l e c t r o d e s . Vis­ cose c o n d u c t i v i t y i s p r i m a r i l of f r e e NaOH and c e l l u l o s e accomplished by movement of N a and OH" i o n s . An i n c r e a s i n g c o n c e n t r a t i o n of c e l l u l o s e i n a g e l decreases the l o c a l concen­ t r a t i o n of NaOH and the ease w i t h which ions move through i t . The C o u l t e r counter i s u s u a l l y c a l i b r a t e d using some uniformly s i z e d non-conducting p a r t i c l e s . I t i s then assumed that amy p a r t i c l e i n v i s c o s e , which has the same e f f e c t on c o n d u c t i v i t y , has the same dimensions. This i s obviously erroneous s i n c e c e l l u l o s e g e l s may have c o n d u c t i v i t y near that of the suspend­ ing f l u i d . I f the s p e c i f i c c o n d u c t i v i t y i s f o u r times that of the non-conducting c a l i b r a t i n g p a r t i c l e , the measured s i z e w i l l be 1/4 the a c t u a l s i z e . I f a s i g n i f i c a n t p o r t i o n of p a r t i c l e s c l a s s i f i e d 4-8μ are i n r e a l i t y gels 16-64y i n diameter, then the d i f f i c u l t i e s i n r e l a t i n g p a r t i c l e count to the e f f e c t on f i l t e r s and spinning becomes more i n t e l l i g i b l e . I t has been pointed out that i t i s v e r y important to d i l u t e v i s c o s e f o r conductometrie counting so t h a t the c o n c e n t r a t i o n of f r e e NaOH i s not changed. The e f f e c t of d i l u t i n g , which can cause changes i n the extent of s o l v a t i o n and mechanical degradation due to mixing on the p a r t i c l e s i z e and d i s t r i b u t i o n , had not been established. +

I n recent years, equipment f o r p a r t i c l e count measurement, based on changes i n l i g h t transmission, has been developed (6)· This equipment can be used with u n d i l u t e d v i s c o s e , the measure­ ments thus being more r e p r e s e n t a t i v e of the v i s c o s e s o l u t i o n at the various process stages from which samples may be taken. The equipment i s i l l u s t r a t e d i n Figure 1. I t c o n s i s t s of two b a s i c u n i t s , the sensor and the counter. A constant volume pump was used to feed v i s c o s e through the sensor. For l e s s v i s c o u s l i q u i d s , constant flow rates were obtained w i t h a b o t t l e sampling device using p r e s s u r i z e d a i r or n i t r o g e n . The b a s i c operation of t h i s equipment i s s t r a i g h t f o r w a r d (Figure 2) examination of a sample taking two minutes once the sensor has been flushed w i t h the sample. The sample flows through a small rectangular f l u i d passage past a window.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

1.

DYER

AND SMITH

Studying

Particles

in

5

Viscose

TABLE I AN OUTLINE OF THE VISCOSE PROCESS PUjLP

ISTEEPI

[PRESSχaSHRÊD] I AGE XANTHATE

X MIX

HZ AGE recovery of cellulose as fiber or film by decomposing the derivative.

|VuASHaFINISH|

RAYON

Pacific Scientific Co. Figure 1.

The HI AC automatic

particle counter

(11)

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

6

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

P a r t i c l e s i n the f l u i d pass by the window one by one as long as s p e c i f i e d l i m i t s of p a r t i c l e c o n c e n t r a t i o n a r e not exceeded. L i g h t from a tungsten lamp i s formed by the window t o a p a r a l l e l beam of exact s i z e and d i r e c t e d onto a photodetector. Using the l i g h t i n t e n s i t y a d j u s t , the operator e s t a b l i s h e s the proper base v o l t a g e from the photodetector as i n d i c a t e d on the p a n e l base output meter. Each p a r t i c l e , as i t passes the window, i n t e r ­ rupts a p o r t i o n of the l i g h t beam according to i t s s i z e . This causes a s p e c i f i c r e d u c t i o n ( o r p u l s e ) i n the v o l t a g e which i s p r o p o r t i o n a l t o the s i z e o f the p a r t i c l e . F i v e counting c i r ­ c u i t s (channels) with p r e s e t thresholds t a l l y the p a r t i c l e s by s i z e . A s i z e range adjustment i s provided f o r each channel t o permit the operator t o s e l e c t any d e s i r e d s i z e ranges. A b u i l t i n c a l i b r a t i o n p u l s e generato erence pulses t o simulat v e r i f y i n g the s i z e ranges. The p a r t i c l e count i s r e g i s t e r e d i n each channel as e i t h e r t o t a l - the t o t a l number l a r g e r than the s i z e f o r which the channel i s s e t or D e l t a - the number l a r g e r than the s e t t i n g of that channel but s m a l l e r than the s e t t i n g of the next h i g h e r channel. For the s t u d i e s d e s c r i b e d i n t h i s paper, the D e l t a mode was used. Various s i z e d sensors are a v a i l a b l e . One convenient f o r use with v i s c o s e i s a 5-150D sensor. Sensor dimensions f o r the c o n s t r i c t e d passage through the l i g h t beam shown i n F i g u r e 2 are 150μ square by 2450μ deep. P a r t i c l e s are s i z e d according to the extent t o which they i n t e r r u p t the l i g h t beam. The d i f ­ ferent o r i e n t a t i o n s of an i r r e g u l a r p a r t i c l e passing through the sensor produces an output more c l o s e l y r e l a t e d to the a c t u a l s i z e of the p a r t i c l e than would a m i c r o s c o p i c examination i n a static field. A l l p a r t i c l e s i n the l i g h t beam a t any one time are counted as one p a r t i c l e of s i z e p r o p o r t i o n a l to the excluded l i g h t beam. A l a r g e number of s m a l l p a r t i c l e s : w i l l appear as a s i n g l e l a r g e p a r t i c l e . This phenomena of " c o i n c i d e n c e " i s avoided by s p e c i ­ f y i n g that there should be no more than one p a r t i c l e i n t e n sen­ sor volumes. For the 5-150D sensor, there are 17000 sensor volumes per c . c , e s t a b l i s h i n g a l i m i t o f 1700 p a r t i c l e s p e r c.c. of sample. The 5-150D sensor i s s u i t a b l e f o r use w i t h v i s c o s e s having v i s c o s i t y of up to about 300 p o i s e s . Higher v i s c o s i t y s o l u ­ t i o n s can be examined - t h e sensor w i l l withstand pressures of 2000 p s i but problems with blockage and c l e a n i n g of the sensor increase substantially at high v i s c o s i t y . The flow rate used f o r v i s c o s e was 36.5 g/m; the p a r t i c l e counts have been reported on a per gram b a s i s c a l c u l a t e d from the counts determined over a t o t a l time p e r i o d of two minutes. The r e p r o d u c i b i l i t y of the count data i s good; r e s u l t s f o r t e n consecutive counts each of twelve seconds on a s i n g l e v i s c o s e are given with averages and standard d e v i a t i o n s of the measure-

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

1.

DYER A N D SMITH

Studying Particles

in Viscose

7

ment i n Table I I . Since p a r t i c l e s should not be removed from the sample during the counting, samples can be r e c y c l e d o r used i n f u r t h e r experiments but care must be taken to avoid contaminat i o n with a i r . Results given i n Table I I I were f o r a f i l t e r e d v i s c o s e with and without a i r and with two r e c y c l e s on each sample. The i n c l u s i o n of only a s m a l l q u a n t i t y of a i r (about 0.5 cc/100 g) i n the v i s c o s e had a pronounced e f f e c t on the p a r t i c l e count. The change i n the p a r t i c l e count on r e c y c l i n g i n d i c a t e s that s m a l l amounts of a i r were trapped i n the v i s c o s e with each c y c l e ; the number of l a r g e p a r t i c l e s apparently i n c r e a s e d and the number o f s m a l l p a r t i c l e s decreased. When there was an a p p r e c i a b l e amount of a i r i n the v i s c o s e , some deaeration occurred during the part i c l e count measuremen shows a decrease i n l a r g number of s m a l l p a r t i c l e s . In the e a r l y stages of e v a l u a t i n g the HIAC p a r t i c l e counter, a t t e n t i o n was d i r e c t e d toward r e s o l v i n g the q u e s t i o n of what changes occur on d i l u t i n g v i s c o s e . A comparison was made of part i c l e counts on v i s c o s e s using the C o u l t e r counter and HIAG counter. Both d i l u t e d and u n d i l u t e d v i s c o s e s were examined with the l a t t e r equipment. The number of p a r t i c l e s counted i n v i s c o s e by the C o u l t e r counter and HIAC counter was very d i f f e r e n t , being much g r e a t e r f o r the HIAC as seen i n Table IV. T h i s was p r e d i c t e d because one method counts changes i n an e l e c t r i c f i e l d while the other counts changes i n l i g h t t r a n s m i s s i o n . F o r the Coulter count the v i s c o s e was d i l u t e d 1:6 using 6% NaOH. The sample i s changed by d i l u t i o n . The HIAC shows the number of s m a l l p a r t i c l e s i s g r e a t l y increased i n the d i l u t e d samples. A c l o s e r examination of the e f f e c t of d i l u t i n g v i s c o s e was made. A standard v i s c o s e was mixed i n v a r i o u s p r o p o r t i o n s with 6.45% NaOH. HIAC p a r t i c l e counts per gram of sample measured on the v i s c o s e , the d i l u t e d samples and the d i l u e n t are g i v e n i n Table V. The p a r t i c l e d i s t r i b u t i o n was a l s o c a l c u l a t e d from the measured d i s t r i b u t i o n i n the u n d i l u t e d v i s c o s e and c a u s t i c . G e n e r a l l y , the number of l a r g e p a r t i c l e s decreased i n p r o p o r t i o n to the d i l u t i o n but the s m a l l p a r t i c l e count was r e l a t i v e l y una f f e c t e d . S i m i l a r c a l c u l a t e d and measured p a r t i c l e d i s t r i b u t i o n s have been observed f o r other v i s c o s e d i l u t e d 1:10 with c a u s t i c or water. To a c e r t a i n extent, t h i s observation i s the r e s u l t of coi n c i d e n c e . But, a t 1:4 and 1:10 d i l u t i o n , the t o t a l number of p a r t i c l e s c a l c u l a t e d i s a p p r e c i a b l y l e s s than the 1:10 c o i n c i dence l i m i t of 1700 p a r t i c l e s per c.c. or one p a r t i c l e i n every 10 sensor volumes. As w i l l be shown l a t e r , there have been r e a l changes i n the nature and number of p a r t i c l e s on d i l u t i n g v i s cose, many more of the p a r t i c l e s can be removed by f i l t e r i n g the d i l u t e d v i s c o s e than when the u n d i l u t e d v i s c o s e i s f i l t e r e d .

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

8

tfPU FLUID FLUID PASSAGE

P

A

m B k S i

OUTPUT METER

PHOTOOETECTOR

SIZE RANGE ADJUSTMENT

* LIGHT INTENSITY ADJUST

X Ο Ο Ο Ο ΟΟ ο ο ο ο ο ο Pacific Scientific Co. Figure 2. The HIAC auto­ matic particle counter (11)

CALIBRATION PULSE GENERATOR

TABLE I I R e p r o d u c i b i l i t y of HIAC P a r t i c l e 12 Second Count # at 36.5 g/m i

5

Count

ί

P a r t i c l e s / g Viscose 3G 10 ί 15

Ι

975

734

128

? f

60μ î

I

1

1789

2

1717

954

731

137

11.8

3

1680

928

728

132

12.8

4

1770

978

749

126

7.6

5

1767

953

727

137

9.2

6

1746

934

735

124

9.9

7

1693

944

717

133

8.3

8

1818

972

734

126

8.9

9

1720

955

737

126

12.2

10

1706

925

740

141

12.2

Average

1741

952

734

131

10.1

45

19

8.5

5.9

1.9

Standard Deviation

8.6 i ι

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

1.

Studying

DYER A N D SMITH

Particles

in Viscose

TABLE I I I E f f e c t of A i r and R e c y c l i n g Sample

Sample

it Times Recycled

Viscose

0

3559

233

1

3402

2 Viscose + A i r

Particles/g 10 15

30

60μ

24

6

2.6

225

27

9

3.6

3142

203

34

15

6.4

1

64

67

223

408

368

2

90

83

255

443

266

5

0

I î

Λ

TABLE IV Comparison of HIAC and C o u l t e r Counts P a r t i c l e Count/g. HIAC Coultei (7-30μ) (8-32u) u d

Viscose Sample

Filtered

Ratio HIAC/Coulter d u

A

452

3771

2000

8.3

4.4

Β

78

1867

2297

23.9

29.5

C

262

: 3639

1978

13.9

7.6

ι

Unfiltered D

969

11911

2534

12.3

2.6

Ε

! 4333

\ 5334

6609

1.2

ι..

d:

diluted

u:

undiluted

;

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

10

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

This i s shown by the r e s u l t s given i n Table V I . The f i l t e r medium was g l a s s f i b e r paper. P a r t i c l e counts b e f o r e and a f t e r f i l t r a t i o n of the u n d i l u t e d v i s c o s e , the v i s c o s e d i l u t e d 1:10 with 6.2% NaOH and 1:10 with water and f o r the mixer charge and d i l u e n t s , show that only a few of the l a r g e r p a r t i c l e s were r e ­ moved from u n d i l u t e d v i s c o s e . P a r t i c l e removal from the d i l u t e d v i s c o s e was much more e f f e c t i v e , the p a r t i c l e counts on the f i l ­ t r a t e being s i m i l a r to those measured f o r the f i l t e r e d d i l u e n t s . Two f i l t e r a b i l i t y t e s t s have been widely used f o r e v a l u a t ­ ing v i s c o s e q u a l i t y . One i s the t e s t based on v i s c o s e flow through a standard f i l t e r medium a t constant p r e s s u r e . The other t e s t uses a constant flow and the f i l t r a t i o n "T" value i s c a l c u l a t e d from t h e pressure b u i l d - u p P a r t i c l e counts measured on v i s c o s e , a f t e r f i l t e r i n χ 63.5 micron diameter s t a n t flow r a t e , are compared i n Table V I I . The f i l t e r element was that normally used i n f i l t r a t i o n "T" t e s t - a candle f i l t e r wound with four l a y e r s of cotton y a r n . Constant flow, 29 g/m, was obtained from a volumetric pump and constant pressure, 39 p s i , was obtained using compressed n i t r o g e n . At constant flow r a t e , the pressure build-up was i n s i g n i f i ­ cant when about 500 g v i s c o s e was f i l t e r e d through the candle f i l t e r o r passed through the j e t . The candle f i l t e r removed the l a r g e p a r t i c l e s , causing an apparent i n c r e a s e i n the number of s m a l l p a r t i c l e s from 2200 t o 3200 due t o c o i n c i d e n c e . P a r t i c u ­ l a t e m a t e r i a l s i z e d a t greater than the h o l e dimension (63.5u) was not removed by the j e t under s i m i l a r c o n d i t i o n s of flow. This observation suggests t h a t the l a r g e p a r t i c l e s a r e not s p h e r i c a l . A l l p a r t i c l e s i n the sensor at any one time are counted as one p a r t i c l e of s i z e p r o p o r t i o n a l t o the excluded l i g h t beam. I t i s p o s s i b l e that elongated p a r t i c l e s ( f i b e r s ) w i l l pass through the sensor i n s e v e r a l sensor volumes. The small p a r t i c l e s i n these volumes w i l l not be counted unless the l a r g e p a r t i c l e s a r e removed. A t constant pressure, 39 p s i , the candle f i l t e r again r e ­ moved the l a r g e r p a r t i c l e s and i n c r e a s e d the s m a l l p a r t i c l e count. The same v i s c o s e f i l t e r e d through the j e t a t t h i s p r e s ­ sure appeared t o have an increased number of l a r g e p a r t i c l e s with no change i n the number of s m a l l p a r t i c l e s . There i s some i n d i c a t i o n that p a r t i c l e s i z e i s increased by agglomeration p o s s i b l y o c c u r r i n g during a t r a n s i e n t holdup of the l a r g e r g e l p a r t i c l e s i n the j e t h o l e s . I t i s expected t h a t , i f t h i s does occur, the mechanism could be analogous to s i l t i n g and channel­ ing phenomena and w i l l be i n f l u e n c e d by p a r t i c l e d e f o r m a b i l i t y , the pressure i n the system and d e f e c t s i n the j e t h o l e s . There i s evidence t h a t , a t constant flow r a t e , p a r t i c l e s plugging j e t holes break away and a r e extruded as pressure i n c r e a s e s . Making c e r t a i n assumptions on the average p a r t i c l e s i z e , the t o t a l p a r t i c u l a t e volume i n one c.c. o f the v i s c o s e sample

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

1.

DYER

Studying

AND SMITH

Particles

in Viscose

TABLE V E f f e c t of D i l u t i n g •

Sample

11

Viscose

P a r t i c l e s / g Sam]pie 30 10 15

5

60μ

Undiluted Viscose m.

2849

1059

346

28

5.3

D i l u t e d Viscose 2:3 c.

2055

715

237

22

3.8

m.

2999

866

266

22

3.2

1:2 c.

1659

543

182

19

3.1

1:4 c .

1063

285

100

14

2

m.

2316

390

133

19

1.9

706

130

51

11

1.3

m.

2300

397

129

11

.5

m.

468

27 ι ,,

18

9

1:10 c.

6.45% NaOH m. measured

!

·* 1

c. c a l c u l a t e d

TABLE VI E f f e c t of D i l u t i n g ι Sample

5

Viscose P a r t i c l e s / g Sample 30 10 15

60y

Γ ί Viscose

U

1944

855

507

84

6.7

i

F

1945

792

463

72

5.6

1781

250

94

15

1.5

51

15

1

.2

' 2476

302

101

10

.8

i

\ Viscose D i l .

U

1

•i

1:10 w 6.2% NaOH

F

Viscose D i l .

U

1:10 w H2O

F

; 266

46

21

1

.3

6.2% NaOH

F

250

46

23

2

.1

H0

F

ί 410

37

23

2

0

2

U:

unfiltered,

: 661

1—

F : filtered

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

12

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

was c a l c u l a t e d . The r e s u l t s a r e shown i n Table V I I I . In t h i s case, c o i n c i d e n c e has much l e s s impact on the d i s t r i b u t i o n s i n c e , although a much l a r g e r number of s m a l l p a r t i c l e s are counted a f t e r the l a r g e p a r t i c l e s have been removed, the i n crease i n p a r t i c u l a t e volume due to the s m a l l p a r t i c l e s i s a r e l a t i v e l y s m a l l f r a c t i o n o f the t o t a l p a r t i c u l a t e volume. These r e s u l t s show that p a r t i c u l a t e m a t e r i a l was removed by the candle f i l t e r but not by the j e t . T h i s i s not unexpected s i n c e the l a r g e r p a r t i c l e s are not s p h e r i c a l and w i l l be able to pass through the 63.5 micron diameter h o l e s . In the next experiment v i s c o s e was passed through a 325 mesh, s t a i n l e s s s t e e l s c r e e n i n which the openings were a p p r o x i mately 50 microns square. The p a r t i c l e counts and f i l t e r a b i l i t y measurements shown i n though the screen was no h a l f of the p a r t i c l e s i n the 30 and 60y counts and the f i l t e r a b i l i t y improved (a low "T" v a l u e corresponds to improved f i l t e r a b i l i t y ) . A p o r t i o n of the r e s i d u e was removed from the s c r e e n there was i n s u f f i c i e n t f o r p a r t i c l e count - and mixed with the u n f i l t e r e d v i s c o s e . As expected, the number of l a r g e p a r t i c l e s i n c r e a s e d and the f i l t e r a b i l i t y was a d v e r s e l y a f f e c t e d . The e f f e c t of c o i n c i d e n c e on the s m a l l p a r t i c l e count i s e v i d e n t . Much e f f o r t has been expended to show c o r r e l a t i o n between f i l t e r a b i l i t y measurements and some f u n c t i o n of a p a r t i c l e count or d i s t r i b u t i o n . The very l i m i t e d success of those e f f o r t s has l e d to arguments of e x p l a n a t i o n . The statements of p a r t i c l e s i z e d i s t r i b u t i o n say l i t t l e , i f anything, about the nature of the p a r t i c l e s o r t h e i r shape. T r e i b e r (7) has r e c e n t l y s t u d i e d the shapes of p a r t i c l e s r e movable by f i l t r a t i o n ; a s i m i l a r study was a l s o suggested by Meskat ( 8 ) . Both have recognized the p o s s i b i l i t y that many of th.e p a r t i c l e s are deformable g e l s . The e l a b o r a t e v i s c o s e g e l f r a c t i o n a t i o n procedure used by Durso and Parks (9) i n v o l v e s d i l u t i o n and consequently cannot avoid changes i n p a r t i c l e number and s i z e . I t i s suggested that the e x i s t i n g data i s s u f f i c i e n t to conclude that w i t h i n a body o f v i s c o s e (e.g. 1 gX there e x i s t s thousands of p a r t i c l e s having a wide d i s t r i b u t i o n of s i z e s , shapes and v i s c o s i t i e s o r d e f o r m a b i l i t i e s . The range of v i s c o s i t i e s at the micro l e v e l i s probably from that of the s o l v e n t to the extremely h i g h v a l u e s o f p o o r l y s u b s t i t u t e d a l k a l i c e l l u l o s e f i b e r s . A l k a l i c e l l u l o s e does not flow at 40,000 p s i but, as seen on the macro s c a l e , even p o o r l y xanthated a l k a l i c e l l u lose flows at 1000 p s i . The problem of f i l t r a t i o n may then be i n t e r p r e t e d as a f u n c t i o n of the behavior of many d i f f e r e n t s m a l l volumes o r masses of v a r i o u s v i s c o s i t i e s . Those p a r t i c l e s having dimens i o n s s m a l l e r than the f i l t e r openings w i l l probably pass through r e a d i l y . As the s i z e of the p a r t i c l e approaches that of

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

1.

DYER A N D SMITH

Studying

Particles

in

13

Viscose

TABLE V I I E f f e c t of F i l t e r i n g

1 Unfiltered

Particles/g Viscose 30 j 15 10

5

Sample Condi t i o n

60y

2197

1785

1518

34

2.6

3262

1549

296

2.4

0.4

Filter

3009

1761

610

7.2

1.4

Jet

2193

1755

1529

60

Constant Flow Filter Jet Constant P r e s s u r e

-

5.4 ! 1

TABLE V I I I E f f e c t of F i l t e r i n g • • « 6" P a r t i c u l a t e Volume cm χ 10 60μ Ί 30 15 10 5

1

J

Sample C o n d i t i o n

Σ

.40

1.61

6.33

1.21

.78

10.33

Filter

.59

1.39

1.22

.08

.11

3.39

Jet

.39

1.58

6.19

1.21

.75

10.12

Filter

.54

1.58

2.55

.26

.40

5.34

Jet

.39

1.58

6.38

2.18

1.56

12.09

Unfiltered Constant Flow

Constant Pressure

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

14

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

the f i l t e r opening, i t w i l l pass through a t some speed d e t e r ­ mined by i t s v i s c o s i t y and the pressure gradient or i t may b l o c k the passage i f i t i s not deformable by the f o r c e s around it. P a r t i c l e s l a r g e r than the passage, i f not deformable at the r e l a t i v e l y low pressure d i f f e r e n t i a l across t h e i r dimensions, w i l l simply b r i d g e across the f i l t e r openings and become p a r t of the f i l t e r . The l a r g e r p a r t i c l e s , which are deformable, w i l l , of course, pass through or b l o c k passages i n s i d e the f i l t e r as determined by v i s c o s i t y and p r e s s u r e . Hermans and Bredee (10) have shown that f i l t r a t i o n of v i s ­ cous l i q u i d s follows one of four f i l t r a t i o n laws. These are, i n order of i n c r e a s i n g s e v e r i t y ; sludge, intermediate, standard and pure choking. Most v i s c o s e s f o l l o w the intermediate law when the blockage rat 2.303 l o g P/P

0

= Kt

where Ρ = p r e s s u r e drop across the f i l t e r at any P

0

time

= i n i t i a l pressure drop

t

= time

Κ

= f i l t r a t i o n constant

w

= r e s i s t a n c e of f i l t e r a t time t .

Some v i s c o s e s obey the standard

-±-

sT^

law:

- - L -

- Kt

v/Po"

3/2 In t h i s case, the blockage rate i s ' . The p a r t i c l e s i n the v i s c o s e form a l a y e r around the i n s i d e of the pores of the f i l t e r media, g r a d u a l l y plugging them. A problem i n e v a l u a t i n g v i s c o s e i s t h a t not only can the p a r t i c l e s deform but the f i l t e r media i s not r i g i d and there i s a broad spectrum of r a t e s f o r the plugging of i n d i v i d u a l pores. In the manufacture of rayon, there w i l l s t i l l be many par­ t i c l e s i n the v i s c o s e when i t i s extruded through the j e t , even though i t has been f i l t e r e d s e v e r a l times. The j e t contains r e l a t i v e l y few l a r g e h o l e s compared to the v e r y numerous s m a l l pores of the f i l t e r media. The passage of p a r t i c l e s through j e t holes i s a random event. I t was speculated, assuming uniform dimensions f o r the h o l e s , that j e t h o l e plugging a l s o would occur randomly. At constant flow r a t e , the plugging of some h o l e s w i l l cause i n ­ creased flow through the other h o l e s . To study t h i s e f f e c t , two

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

1.

DYER AND SMITH

Studying

Particles in

Viscose

15

j e t s , one w i t h l a r g e h o l e s (980 χ 3.5 m i l diameter) and one w i t h 1500 s m a l l holes (2 m i l diameter) were connected to a common v i s ­ cose supply from a volumetric pump or a p r e s s u r i z e d c o n t a i n e r . The setup i s o u t l i n e d i n Figure 3. The t e s t was made at con­ s t a n t flow r a t e or constant pressure, recording at convenient time i n t e r v a l s the amount of v i s c o s e d e l i v e r e d from each j e t . Large p a r t i c l e s , >3.5 m i l , b l o c k both j e t s randomly and, gen­ e r a l l y , to s i m i l a r extents. P a r t i c l e s 2-3.5 m i l w i l l not pass f r e e l y through j e t A but are expected to pass through the h o l e s of j e t Β though, perhaps, not without some e f f e c t . Small par­ t i c l e s , >2 m i l , w i l l pass through the holes i n both j e t s u n t i l t h e i r passage i s r e s t r i c t e d as the h o l e s p l u g . T h i s occurs f i r s t i n the small h o l e j e t as p a r t i c l e s are deposited by a f i l ­ t r a t i o n mechanism. Th through the s m a l l h o l Examples of measurements made a t constant flow and at constant pressure are given i n Table X. The change i n flow d i s t r i b u t i o n i s measured as the r a t i o of the flow through the two j e t s . Accompanying the change at constant t o t a l flow, pressure b u i l d s up and w i l l e v e n t u a l l y cause p a r t i c l e s to break loose and be ex­ truded and the flow p a t t e r n w i l l become e r r a t i c . This i s not seen i n t h i s example. The pressure at which t h i s occurs appears to be r e l a t e d to the d e f o r m a b i l i t y of the p a r t i c l e s plugging the h o l e s . At constant pressure, the t o t a l flow i s decreased as the j e t holes p l u g . Both streams are a f f e c t e d i n the same way with the flow from the s m a l l h o l e j e t being reduced to 25% and from the l a r g e h o l e j e t to 87% of t h e i r o r i g i n a l values over a 60 minute p e r i o d . At constant pressure, the flow w i l l e v e n t u a l l y stop when a l l the holes are completely plugged. The r e s u l t s i n t h i s t a b l e (Table X) were obtained using an u n f i l t e r e d v i s c o s e . They show the method - D i f f e r e n t i a l Flow appears to have s i g n i f i c a n t p o t e n t i a l f o r use i n e v a l u a t i n g v i s ­ cose f i l t e r i n g q u a l i t y , perhaps even spinning q u a l i t y . In p r a c t i c e , v i s c o s e i s f i l t e r e d before s p i n n i n g . The j e t h o l e plugging c h a r a c t e r i s t i c of the f i l t e r e d v i s c o s e , although i t contains numerous p a r t i c l e s that have passed through the f i l t e r s f o r reasons of s i z e , shape or d e f o r m a b i l i t y p r o p e r t i e s , i s ex­ pected to be q u i t e d i f f e r e n t to that f o r an u n f i l t e r e d v i s c o s e . A comparison of r e s u l t s from the d i f f e r e n t i a l flow t e s t on f i l t e r e d and u n f i l t e r e d v i s c o s e at constant t o t a l f l o w i s g i v e n i n Table X I . S u b s t a n t i a l pressure build-up was observed with the u n f i l t e r e d v i s c o s e to the p o i n t where p a r t i c u l a t e m a t e r i a l was extruded from plugged h o l e s and the f l o w r a t i o became e r r a t i c . With the f i l t e r e d v i s c o s e , there was no pressure b u i l d ­ up and no s i g n i f i c a n t change i n the flow r a t i o . F i l t e r i n g had removed the p a r t i c l e s causing j e t h o l e p l u g g i n g . In c o n c l u s i o n , the HIAC p a r t i c l e counter i s used w i t h un­ d i l u t e d v i s c o s e , a v o i d i n g changes caused when the sample i s

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

TABLE IX E f f e c t of F i l t e r i n g Particles/g 5 10

Sample

Viscose 15 30 I 60μ

Filterability

Unfiltered

3258

1394

440

37

9

14.8

Filtered

3278

1472

433

20

4

10.0

Unfiltered + Residue

Constant

Viscose

Pressure

Supply

Viscose Supply

Jet

2 mil

Figure S.

Jet

3.5 m i l

Differential flow test

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

8.66

7.17

5.04

3.70

2.98

0

15

30

45

60

Time (min. )

24.04

23.67

21.89

20.35

17.79

Constant Flow 27 g/m Jet A Jet Β 1500 Holes 980 Holes (2 m i l ) (3.5 m i l )

28

25

24

20

18

psi

8.07

6.40

4.34

2.84

2.05

B/A

....... ^ . , . . .

.....

1.92

2.42

3.49

5.02

7.83

...

13.13

13.53

13.82

14.43

15.05

15.05

15.95

17.31

19.45

22.88

g/m Constant Pressure 20 p s i Jet A Jet Β 1500 Holes 980 Holes (2 m i l ) (3.5 m i l ) Flow

V i s c o s e Flow

D i f f e r e n t i a l Flow T e s t a t Constant Flow Rate and Constant P r e s s u r e

TABLE Χ

6.84

5.59

3.96

2.87

1.92

B/A

18

T E X T I L E AND

VO

PAPER CHEMISTRY AND

CO

00 CO ι

rH•

rH•

rH•

rH•


CM

< r CM

CM


rH

m 0•

CM

\

CO

CO

PQ

iH•

rH•


00

co

rH

TECHNOLOGY

•H

co &

CO ^ CD rH

Ό

o W HΟ «Hg î-ι ω 4-J ni u eu m rH »-D 0 · •H m co en ^

•

m rH

m CM

CM

VO

• vO

VO

VO

VO

rH

rH

rH

rH

rH

•

un

•

m

•

CO

eu

^ ιΗ <1 Ο

^

m

m

iH

rH• rH

rH• rH

m

Ο

rH•

CM•

co CM

H

ÎTl - H

•

CD Ο CO CM

h

0

m

m

rH• rH

rH• rH

rH• rH

Ο m • m

m rH

VO

• co

m co

m
m m

CM

rH

mm

σ> ^

rH P»4 CU CO

<1

Ο υ CO

•H

>

00

r>. 00

•

•

•H

co P.

CO /-> CU rH rH «H

eu eu PQ 4J

0

ιΗ «H

B

• rH

m m

rH CM

CM• CM

cri

rH

rH• CM

rH• CM

m

m ΙΛ

rH

lO CM

m

ON•

es

eu m m h o · m co α 5=3 co w

m

LO ON

^ ΤΗ


Tl

eu CO o M 0> ν-/

h

m ON•

VO

•

•

m

•

st

•

;

CU

S

•H

0 -H g

Ο rH

0 CM

0 CO

0

Ο

m

0 vO

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

1. DYER AND SMITH

Studying Particles in Viscose

19

diluted for conduc tome t r i e counting. The measurements were thus more representative of the viscose solution at the various process stages from which the samples were taken. It is pro­ bable that a test to evaluate the deformability of viscose par­ t i c l e s can be developed using the particle count before and after f i l t e r i n g under different applied pressures. To detect the effect of particles i n filtered viscose, the pore dimensions must be much smaller than normal jet holes. As described i n this paper, the differential flow method was insensitive to particles i n f i l t e r e d viscose because the jet hole sizes used were too large. It i s suggested that useful i n ­ formation about viscose particles could be obtained by using f i l t e r media of controlled pore size rather than the jets. Literature Cited 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

Samuelson, O., Svensk Papperstidn. 52 465 (1949). Treiber, E., J. Poly. Sci., 51, 297 (1961). Arnold, A., Philipp, B . , and Schleicher, Η . , Faser­ forsch u. Textiltech. 21 361 (1970). Zubakhina, N. L., Serkov, A. T . , and Virezub, A. I., Khim. Volokna, 14 33 (1972). Treiber, E., and Nadziakiewicz, H. C., J. Poly. S c i . Part C (2) 357 (1963). Krueger, E . O., B u l l . Parenteral Drug Assoc., 26, 2 (1972). Treiber, E., Lensinger Berichte, 18 5, 12 (1965). Treiber, E., Faserforsch u Textiltech. 15 618 (1964). Durso, D. F., and Parks, L. R . , Svensk Papperstidn. 64 853 (1961). Hermans, P. H., and Bredee, H. L., Rec. Trav. Chim. Pays-Bas 54 680 (1935). Figures 1 and 2 reproduced by kind permission of HIAC Instruments Division, Pacific Scientific Company, P.O. Box 3007, Montclair, California 91763.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

2 Cellulose: Pores, Internal Surfaces, and the Water Interface STANLEY P. ROWLAND Southern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, New Orleans, LA 70179 The microstructur formance properties, bu of pores that are critical to moisture regain, imbibed water, and the modification of fibers with finishes that must enter fibers in order to perform their function. In the case of cellulosic fibers, most specifically cotton fibers, pores allow penetration of dyes, polymerizable monomers, and cellulose-reactive reagents. Additionally, pores provide space for polymer deposition and hydroxy1-rich surfaces for sorption and reaction. Flame-retarding finishes for cotton generally operate by deposition of insoluble phosphorus- and nitrogen-containing polymers, for which pore volume is important. Conventional shape-retentive finishes, on the other hand, operate by formation of covalent linkages from reagent to cellulosic hydroxyl groups, for which pore surfaces are important. In both cases, the finishes are generally more effective or more durable, or the products exhibit better balances of textile properties when the degree of penetration is greater. Considering the practical importance of chemical finishing of cellulosic fibers and the increasingly sophisticated requirements for performance qualities of textile fabrics, the current state of our knowledge concerning penetration of water-soluble solutes into cotton fibers and interactions of the solutes with pore surfaces is less than adequate. The purpose of this review is to examine evidence from several approaches and methods concerning the nature of water in pores of cellulosic fibers and to examine the nature of interactions of solutes in aqueous solution with pore walls of cellulose. Pore formation, bound water, nonsolvent water, inaccessible water, solute-pore wall interaction, and the structure of water near cellulose surfaces are considered in sequence in order to develop an overall perspective and a conceptual model for the manner in which water is held and behaves in cellulosic fibers. A chronological approach is taken within each section for orientation, and a summarizing 20

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paragraph i s appended i n a p p r o p r i a t e s e c t i o n s f o r b r i e f e v a l u a t i o n of the r e s u l t s i n that area of research. Overall, the primary o b j e c t i v e of the e x e r c i s e i s to b e t t e r understand c e r t a i n aspects o f i n t e r a c t i o n s of chemical f i n i s h i n g agents w i t h c o t t o n c e l l u l o s e (and other c e l l u l o s i c s u b s t r a t e s ) , s i n c e t h e r e i n would appear to l i e the key to achievement of new and optimum balances i n performance p r o p e r t i e s . Pore Formation Pores a r i s e from d i s c o n t i n u i t i e s of molecular packing i n polymeric s u b s t r a t e s . More s p e c i f i c a l l y , i n the case of f i b e r s , pores develop from submicroscopic and s u b e l e c t r o n microscopic imperfection i l a t e r a l packin f microstruc t u r a l elements. Network e x i s t i n s u b s t a n t i a l amount typica y (la), channels and pores are opened up on exposure to s u i t a b l e agents. The pore model of p e n e t r a t i o n of f i b e r s i s tenable i n s o f a r as the major p o r t i o n of the network of channels and pores i s created by i n t e r - and i n t r a f i b r i l l a r s w e l l i n g agents. R e l a t i v e p e n e t r a t i n g a b i l i t i e s are i l l u s t r a t e d i n s o r p t i o n of water vapor and organic vapors by c o t t o n and rayon f i b e r s at a s p e c i f i c r e l a t i v e vapor p r e s s u r e . S o r p t i o n i s p r o p o r t i o n a l to hydrogen bonding c a p a c i t y of the agent: i . e . , water > a c e t i c a c i d > methanol > ethanol > l e s s p o l a r organic agents (lb)· Swelling of cotton measured by yarn u n t w i s t i n g and by increase i n f i b e r width, which are i n q u a l i t a t i v e agreement (2), shows a s i m i l a r sequence w i t h decreasing hydrogen-bonding c a p a c i t y . Agents t h a t are s l i g h t l y stronger than water i n hydrogen bonding (e.g., formic a c i d , d i l u t e s a l t s o l u t i o n s , and d i l u t e base s o l u t i o n s ) appear to reach l i m i t s of i n t e r f i b r i l l a r p e n e t r a t i o n and s w e l l i n g , whereas agents that are s u b s t a n t i a l l y stronger than water i n d i s r u p t i n g hydrogen bonds and t h a t a s s o c i a t e s t r o n g l y with the c e l l u l o s i c hydroxyl groups (e.g., l i q u i d ammonia, ethylenediamine, and m e r c e r i z i n g a l k a l i s ) a c t as i n t r a f i b r i l l a r s w e l l i n g and d e c r y s t a l l i z i n g agents. For both i n t e r - and i n t r a f i b r i l l a r s w e l l i n g , the opening up of a network of channels and pores i n the f i b e r depends upon p e n e t r a t i o n of the agent; t h a t , i n t u r n , depends upon the a b i l i t y of the agent t o d i s r u p t l e s s - o r d e r e d h y d r o x y l i c hydrogen bonds between f i b r i l s , between m i c r o f i b r i l s , and between elementary f i b r i l s , or to d i s r u p t h i g h l y ordered hydrogen bonds w i t h i n elementary f i b r i l s . The s i g n i f i c a n c e o f pores and i n t e r n a l surfaces i s q u i t e evident i n measurements o f surface areas by adsorption of n i t r o g e n , a nonswelling agent, and a p p l i c a t i o n gf the BET equation. Results f o r dry f i b e r s are 0.6-0.7 m /g (3,40, values which agree c l o s e l y w i t h estimates of the area of the e x t e r n a l microscopic f i b e r s u r f a c e . Areas measured w i t h

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vapors o f water, a c e t i c a c i d , methanol, and ethanql a r e , r e s p e c t i v e l y , 137, 18.3, 20.1, and 7.3, m /g ( 5 ) , i n d i c a t i v e of the r e l a t i v e l y l a r g e i n t e r n a l s u r f a c e s t h a t are r e a d i l y developed i n the c o t t o n f i b e r . That the s i t u a t i o n i s dynamic i s shown by the f a c t t h a t pore s t r u c t u r e opened up by water i s r e t a i n e d only to the extent of about 15% a f t e r s o l v e n t exchange through o r g a n i c s o l v e n t s to n i t r o g e n f o r s u r f a c e area measure­ ments ( 6 7 ) · There a r e few p i e c e s o f data t h a t p r o v i d e reasonable b a s i s f o r assessment o f the e f f e c t o f pore s i z e upon p e n e t r a t i o n of t y p i c a l reagents i n t o c o t t o n . One s e t of data (8) deserves mention because i t i l l u s t r a t e s i n t e r e s t i n g d i f f e r e n c e s i n degrees of p e n e t r a t i o n . For p u r i f i e d n a t i v e c o t t o n ^ about 49% of the h y d r o x y l groups (HL 37% are r e a d i l y a c c e s s i b l r e a d i l y a c c e s s i b l e to Ν , Ν - d i e t h y l a z i r i d i n i u c h l o r i d e (mo t 136, r e p r e s e n t a t i v e o f common f i n i s h i n g agents) i n d i l u t e aqueous s o l u t i o n , and an estimated 2.5% of h y d r o x y l i c s u r f a c e s are a c c e s s i b l e t o Diphenyl F a s t Red 5BL(mol wt 676) i n d i l u t e aqueous s o l u t i o n . 9

Two concepts a r e c a l l e d upon to e x p l a i n the v a s t d i f f e r e n c e s of a c c e s s i b i l i t y noted i n the preceding paragraph. (1) Strong i n t e r a c t i o n s between water and c e l l u l o s e may form "bound water" or "nonsolvent water" t h a t s u b s t a n t i a l l y reduces the s w e l l i n g a c t i o n o f the water or the pore volume a v a i l a b l e to s o l u t e s , and (2) channels and pores are a v a i l a b l e i n a range o f s i z e s , some being too s m a l l to accommodate i n g r e s s or passage o f s o l u t e s . The two concepts may be complementary, although they were not n e c e s s a r i l y considered that way i n early research. Bound water on c e l l u l o s i c s u r f a c e s i s the conceptual d e s c r i p t i o n f o r r e d u c t i o n i n thermodynamic a c t i v i t y or i n p a r t i t i o n c o e f f i c i e n t o f s m a l l molecules between the aqueous phase and the c e l l u l o s e polymer phase. E x c l u s i o n of l a r g e r molecules i s conceived to occur on the b a s i s of a s i e v i n g a c t i o n . These concepts a r e d i s c u s s e d i n subsequent sections· Bound Water Considerable accumulated evidence i n d i c a t e s t h a t p a r t of the water w i t h i n a moist c e l l u l o s i c s u b s t r a t e e x h i b i t s p r o p e r t i e s that a r e markedly d i f f e r e n t from those of the r e s t of the water. Only the most p e r t i n e n t p u b l i c a t i o n s on t h i s subject (and s u b j e c t s o f other s e c t i o n s ) are r e f e r e n c e d i n t h i s r e p o r t . F i l b y and Maass ( 9 ) , from measurements of d e n s i t y of moist c e l l u l o s e i n moist helium, found t h a t the apparent d e n s i t y o f adsorbed water was n e a r l y constant a t a v a l u e of about 2.5 times that o f o r d i n a r y water, up to 0.06 g water/g c e l l u l o s e . With f u r t h e r i n c r e a s e s i n moisture content, the

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apparent d e n s i t y of water decreased, becoming normal at about 0.08 g/g. T h e i r c o n c l u s i o n , published i n 1932, was that i n i t i a l water i n c e l l u l o s e i s combined s t r o n g l y and chemically, that f u r t h e r a d d i t i o n o f water i n c r e a s e s the amount of a v a i l a b l e c e l l u l o s i c s u r f a c e , and f i n a l l y t h a t normal l i q u i d water f i l l s the c a p i l l a r i e s . Stamm and Loughborough (10) i n 1935 measured d i f f e r e n t i a l heat of water s o r p t i o n by c e l l u l o s e and wood and showed that p a r t of the water adsorbed by c e l l u l o s e i n v o l v e d e v o l u t i o n of more heat than l a t e r p o r t i o n s o f water. They a l s o showed that the entropy and d i f f e r e n t i a l heat of h y d r a t i o n were independent of temperature below 0.06 g water/g c e l l u l o s e , these p o i n t s being strong arguments i n favor of the hypothesis that water i s bound by chemical f o r c e s t r a n s i t i o n between the wate e v o l u t i o n of heat and that water which i n v o l v e d l e s s e r - t o - z e r o amounts o f heat e v o l u t i o n , zero being reached a t about 0.2 g water/g c e l l u l o s e . In 1947-52, Magne e t a l . (11, 12) measured amounts of f r e e z i n g and nonfreezing water i n moist c e l l u l o s e at -4.5°C. They found t h a t a l l water was n o n f r e e z i n g up to about 0.04 g/g n a t i v e c o t t o n , that about h a l f of the water between 0.04 and 0.15-0.20 g/g was n o n f r e e z i n g , and t h a t a l l of the water above 0.15-0.20 g/g was f r e e z i n g . They found, a l s o , that a l l of the f r e e z i n g water was r e l e a s e d by d e s i c c a t i o n b e f o r e any of the nonfreezing water was r e l e a s e d . A f a i r l y good l i n e a r r e l a t i o n ship was obtained between the amount of i n i t i a l l y adsorbed water ( i . e . , t h a t up to the appearance of f r e e z i n g water) and the n o n c r y s t a l l i n e f r a c t i o n of the c e l l u l o s e . Water i n i t i a l l y adsorbed was considered to be hydrogen-bonded to c e l l u l o s i c h y d r o x y l groups. Following extensive s t u d i e s of s p e c i f i c volume and d e n s i t y of moist c e l l u l o s e , Hermans (13), i n a monograph i n 1946, d i s p e l l e d the concept t h a t i n i t i a l l y adsorbed water was compressed to h i g h d e n s i t y (see above). He showed t h a t d e n s i t y o f c o t t o n rose s l i g h t l y to a maximum at 0.02-0.03 g water/g c o t t o n , that i t dropped r a p i d l y t h e r e a f t e r , and that at 0.10-0.12 g/g the apparent compression of water i n c e l l u l o s e came to an end. H i s e x p l a n a t i o n of these observations was that the i n i t i a l macroscopic s p e c i f i c volume of the c o t t o n f i b e r c o n s i s t s o f the volume occupied by c e l l u l o s e molecules plus a c e r t a i n f r a c t i o n o f empty space, which i s not penetrated by the nonaqueous l i q u i d medium used i n the measurement. As water molecules a r e adsorbed and packed among c e l l u l o s e chains, p a r t o f the empty space i s occupied by water, and the i n c r e a s e i n volume o f the f i b e r i s l e s s than a d d i t i v e . These empty spaces i n c o t t o n are completely occupied a t 0.02-0.03 g water/g c e l l u l o s e . At higher water contents (ca.

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0.10 g/g c o t t o n ) , the s o r b i n g s u r f a c e s are covered w i t h a monolayer o f water molecules and no f u r t h e r empty spaces e x i s t . From t h i s p o i n t onward, s o r p t i o n assumes the character of c a p i l l a r y condensation, and volumes of water and c e l l u l o s e are a d d i t i v e . The same i n t e r p r e t a t i o n i s summarized i n more recent l i t e r a t u r e by Meredith (14), who s t a t e d that these data p r o v i d e b a s i s o n l y f o r d i s t i n g u i s h i n g between the f i r s t monolayer and subsequent c a p i l l a r y water. The s i g n i f i c a n c e o f p u b l i c a t i o n s by Rees (15) and Guthrie (16) i n 1948-9 on heats of a d s o r p t i o n of moisture i n c e l l u l o s e i s w e l l summarized i n a review by Rees (17). D i f f e r e n t i a l heat o f s o r p t i o n (Q^) i s e s s e n t i a l l y the same f o r a l l c e l l u l o s i c f i b e r s , the r e l a t i o n s h i p o f Q and f r e e energy of s o r p t i o n (AG) to humidity b e i n g between the heat and f r e energy t h a t shows by how much the energy of b i n d i n g o f water molecules t o c e l l u l o s i c s u r f a c e s exceeds the sum of energies r e q u i r e d t o remove a molecule o f water from the water phase and t o break c e l l u l o s e - t o - c e l l u l o s e hydrogen bonds. T h i s excess energy (Q - AG) i s shown g r a p h i c a l l y i n F i g u r e 2. Rees concluded t h a t : (1) Excess energy i s g r e a t e s t a t low r e l a t i v e h u m i d i t i e s , i n d i c a t i n g t h a t water molecules are more s t r o n g l y a t t r a c t e d t o c e l l u l o s e a t low r e g a i n s . As more water i s sorbed, the a t t r a c t i v e f o r c e decreases because adsorbed water molecules e x e r t a r e p u l s i v e f o r c e o r because m u l t i l a y e r s o f water molecules a r e formed. (2) The water i n i t i a l l y adsorbed has an excess energy o f about 90 c a l / g , which i s about equal t o the l a t e n t heat of f u s i o n of i c e . Thus, these adsorbed water molecules may be expected to have degrees of o r i e n t a t i o n and a s s o c i a t i o n comparable to those of i c e . The f a c t that the i n i t i a l heat o f s o r p t i o n i s approximately the same as the heat o f formation o f the hydrogen bond has been considered c o n f i r m a t i o n t h a t water i s sorbed by t h i s mechanism. From a more d e t a i l e d study o f heat of wetting o f c o t t o n , Morrison and D z i e c i u c h (18) concluded i n 1959 that adsorbed water forms a complete monomolecular l a y e r of immobilized water molecules a t about 0.03 g water/g c e l l u l o s e , corresponding to a d e f i n i t e break i n the d i f f e r e n t i a l heat curve. Iyer and Baddi (19) confirmed t h i s c o n c l u s i o n and showed that d i f f e r e n t i a l heats o f s o r p t i o n were lower f o r c e l l u l o s e preswollen by solvent exchange (and subsequently d r i e d ) than f o r the o r i g i n a l c e l l u l o s e over the range o f moisture pickup corresponding to the formation o f the monomolecular water l a y e r . These r e s u l t s are c o n s i s t e n t w i t h the p o s s i b i l i t y t h a t r e l e a s e of s t r a i n from m i c r o s t r u c t u r a l elements o f d r i e d and c o l l a p s e d cotton f i b e r s c o n t r i b u t e s i g n i f i c a n t l y to the heat r e l e a s e d when water i s sorbed. In 1965, Ramiah and Goring (20) found that thermal expansion c o e f f i c i e n t s o f water-swollen p e l l e t s of c e l l u l o s e

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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Cellulose:

Pores, Surfaces, and

Relative humidity

Interface

percent interscience

Figure 2. Rehtion of excess energy (Q — AG) and entropy decrease [S = (Q — A G ) / Ύ] to relative humidity (17) L

L

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and r e l a t e d m a t e r i a l s were s e v e r a l times the expansion coeff i c i e n t s measured i n the d r y s t a t e . They proposed that the h y d r o x y l - c o n t a i n i n g s u r f a c e s of the carbohydrate molecules act as s t r u c t u r e breakers and enhance l o c a l c o n c e n t r a t i o n of the unbonded s p e c i e s o f water, which has a much h i g h e r c o e f f i c i e n t of thermal expansion than c l u s t e r s o f water molecules (21). G o r i n g s (22) model f o r the carbohydrate-water i n t e r f a c e i s shown i n F i g u r e 3. Goring (22) and Ramiah and Goring (20) pointed out that the anomalously h i g h thermal expansion i n aqueous media i s due t o the h i g h expansion c o e f f i c i e n t of the perturbed l a y e r o f water and a l s o to the t r a n s f o r m a t i o n of some o f the unbonded water i n the perturbed l a y e r to the l e s s dense normal o r unperturbed water as temperature i s r a i s e d . This i n t e r p r e t a t i o n mad f theorie f s t r u c t u r e proposed by Fran Scheraga (21). Ramiah an g (20) r e s u l t s p r o v i d e d new credence f o r the e a r l i e r concept of F i l b y and Maass ( 9 ) , except that the d e n s i t y o f i n t e r f a c i a l water i s i n c r e a s e d by p e r t u r b a t i o n o f the water s t r u c t u r e r a t h e r than by compression o r a d s o r p t i o n . From thermal expansion c o e f f i c i e n t s , Neal and Goring (24) estimated the amount of perturbed water f o r c o t t o n l i n t e r s t o be 0.04 g/g, a v a l u e g e n e r a l l y s i m i l a r to those a l r e a d y noted f o r bound water. Most r e c e n t l y , i n f o r m a t i o n concerning the concept o f bound water has come from n u c l e a r magnetic resonance (NMR) spectroscopy. From study o f the change o f widths a t h a l f value of peaks i n h i g h r e s o l u t i o n s p e c t r a as a f u n c t i o n of water content o f c e l l u l o s e , Ogiwara et a l . (25) d i s c u s s e d evidence t h a t water i n c e l l u l o s e i s present i n two d i s t i n c t l y d i f f e r e n t s t a t e s o f b i n d i n g . The content o f bound water was reported to be 0.10 g/g c o t t o n and 0.15 to 0.25 g/g wood p u l p , the l a t t e r b e i n g i n f l u e n c e d g r e a t l y by the k i n d and s t a t e of the f i b e r s . Employing p u l s e d NMR spectroscopy, C h i l d (26) observed that molecular motion o f sorbed water molecules depended upon the p h y s i c a l s t a t e o f - t h e c e l l u l o s e , p a r t i c u l a r l y the degree of c r y s t a l l i n i t y . Over a range o f water content up to 0.055 g/g Whatman CF1 (a h i g h l y c r y s t a l l i n e h y d r o c e l l u l o s e ) and 0.09 g/g c o t t o n l i n t e r s , primary s o r p t i o n s i t e s were f i l l e d by water molecules. Sorbed water on c e l l u l o s e was found to be very s t r o n g l y bound, as shown by the p o s i t i o n of the minimum i n r e l a x a t i o n times and by the absence of f r e e z i n g of a l l of the sorbed water on the Whatman CF1 and some of the water i n the c o t t o n l i n t e r s u n t i l about 243°K. C a r l e s and S c a l l a n (27) used h i g h r e s o l u t i o n NMR s p e c t r o scopy and d e v i s e d a method d i f f e r e n t from that of Ogiwara et a l . f o r e s t i m a t i n g the amount of bound water. Because of experimental d i f f i c u l t i e s , o n l y upper l i m i t s of bound water were estimated; these were 0.15 g/g c o t t o n , 0.23 g/g wood, and 1

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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ROWLAND

Cellulose:

Pores, Surfaces, and

Interface

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0.30 and 0.33 g/g f o r two wood p u l p s . C a r l e s and S c a l l a n observed that the presence of c e l l u l o s e caused the water peak to s h i f t to higher magnetic f i e l d s . Such a s h i f t can be due to the breaking of hydrogen bonds, i . e . , to a displacement of e q u i l i b r i u m from the normal d i s t r i b u t i o n of c l u s t e r s toward a higher c o n c e n t r a t i o n of monomeric water molecules. They concluded t h a t water on the s u r f a c e of the c e l l u l o s e i n v o l v e d hydrogen bonds t h a t a r e weaker than those i n c l u s t e r s of water molecules· F r i o x and Nelson (28), u s i n g a pulsed NMR technique, reported d e t e c t i o n and i d e n t i f i c a t i o n of four types of water i n c e l l u l o s e : (1) primary bound, up to 0.09 g/g c o t t o n l i n t e r s , (2) secondary bound, from 0.09 g/g to 0.15-0.20 g/g, which together w i t h primary bound (3) f r e e , which they equat which i s considered to be the water e x t e r n a l to the c e l l w a l l . These authors designated the t r a n s i t i o n between primary and secondary bound water as a p o i n t of p l a s t i c i z a t i o n that i s a s s o c i a t e d w i t h s w e l l i n g of the c e l l u l o s i c s t r u c t u r e to allow increased m o b i l i t y o f c e l l u l o s e c h a i n s . The f o r e g o i n g i n f o r m a t i o n , drawn from divergent types of measurements and approaches, c o n s t i t u t e s p e r s u a s i v e argument f o r the r e a l i t y o f the e x i s t e n c e of bound water on a c c e s s i b l e surfaces o f c e l l u l o s e . While i t may be considered discouraging that there i s so l i t t l e q u a n t i t a t i v e c o r r e l a t i o n among the r e s u l t s generated from the d i f f e r e n t approaches, i t i s p e r t i nent t h a t the v a r i o u s methods assess s l i g h t l y d i f f e r e n t features o f the a s s o c i a t i o n between water and c e l l u l o s e . I t i s encouraging, however, t h a t there i s a general p a t t e r n of consistency that runs throughout the r e s u l t s discussed above. Some evidence noted above p o i n t s toward two s u b s t a n t i a l l y d i f f e r e n t degrees o f s t r o n g b i n d i n g of water to c e l l u l o s e . Such a s i t u a t i o n i s q u a l i t a t i v e l y c o n s i s t e n t w i t h the recent discovery t h a t there a r e two types of a c c e s s i b l e surfaces i n c o t t o n f i b e r s , t h a t these e x i s t i n p u r i f i e d n a t i v e c o t t o n i n the r a t i o 0.36:0.64, and that the abundance of f r e e hydroxyl groups a v a i l a b l e f o r donor and acceptor hydrogen bonding on these two surfaces i s q u i t e d i f f e r e n t (29, 30). The smaller of these two types, which i s probably the more r e a d i l y a c c e s s i b l e , has the g r e a t e r number of hydroxyl groups a v a i l able f o r hydrogen bonding per u n i t of a c c e s s i b l e c e l l u l o s i c s u r f a c e . Thus, the h i g h e s t v a l u e s of excess energy and the strongest a s s o c i a t i o n s o f water and h y d r o x y l i c surfaces may be a t t r i b u t e d to the i n t e r a c t i o n of water w i t h these most r e a d i l y a c c e s s i b l e s u r f a c e s ; the l e s s s t r o n g l y bound water may be that a s s o c i a t e d w i t h s u r f a c e s t h a t a r e l e s s r e a d i l y a c c e s s i b l e and l e s s populated w i t h f r e e hydroxyl groups. Hermans' concept (see above) concerning p e n e t r a t i o n of water i n t o the c o t t o n f i b e r i n three stages ( i . e . , i n i t i a l

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

2.

ROWLAND

Cellulose:

Pores, Surfaces, and

Interface

p e n e t r a t i o n i n t o empty spaces and onto r e l a t e d s u r f a c e s , p e n e t r a t i o n to cover a l l r e a d i l y a c c e s s i b l e surfaces w i t h a monomolecular l a y e r , and subsequent d e p o s i t i o n of c a p i l l a r y water) remains reasonable. But r e s u l t s of Ramiah and Goring (20) provide new substance f o r the e x i s t e n c e of perturbed water w i t h a higher than normal d e n s i t y on c e l l u l o s i c s u r f a c e s . S i m i l a r i t y i n the numerical v a l u e (0.04 g/g) estimated by Neal and Goring (24) f o r the perturbed l a y e r o f water i n c o t t o n l i n t e r s and v a l u e s reported above f o r bound water suggest t h a t these may be one and the same, o r t h a t the perturbed water may c o n s t i t u t e a p o r t i o n o f the t o t a l bound water. The most a c c e s s i b l e s u r f a c e s , to which Hermans r e f e r r e d , are l i k e l y those a s s o c i a t e d w i t h empty spaces, because s t r e s s i n the m i c r o s t r u c t u r a l element packing. Release of s t r a i elements as a r e s u l t o f p l a s t i c i z a t i o n by sorbed water and s e p a r a t i o n of m i c r o s t r u c t u r a l u n i t s appears to c o n t r i b u t e to the o v e r a l l heat e f f e c t i n a manner that i n f l u e n c e s excess energy, which i s p l o t t e d i n F i g u r e 2. Nonsolvent Water E a r l y i n v e s t i g a t o r s i n t h i s f i e l d ( l c , 13b, 31) were concerned w i t h that p o r t i o n of water i n c e l l u l o s e (and other swollen g e l s ) that d i d not a c t as s o l v e n t f o r added s a l t s and other compounds of low molecular weight. They assumed that a p o r t i o n of the a c c e s s i b l e water was so s t r o n g l y bound to the c e l l u l o s e t h a t i t o f f e r e d no solvent a c t i o n f o r the s o l u t e . These s t u d i e s were conducted c o n c u r r e n t l y w i t h those of bound water (preceding s e c t i o n ) , o f t e n w i t h the e x p e c t a t i o n that the two phenomena were the same and without the d i s t i n c t i o n that we make i n t h i s manuscript between nonsolvent water, d i s c u s s e d i n t h i s s e c t i o n , and bound water, already d i s c u s s e d . Champetier (32) i n i t i a t e d t h i s r e s e a r c h i n the e a r l y 1930s by soaking dry c e l l u l o s e f i b e r s i n s o l u t i o n s of sodium t h i o s u l f a t e (mol wt o f anhydrous s a l t 158), p r e s s i n g p o r t i o n s of the l i q u i d out of the f i b e r s w i t h p r o g r e s s i v e l y i n c r e a s i n g pressures, and a n a l y z i n g the exudate and r e s i d u a l f i b e r s . The concentrations of s o l u t e s i n exudates were higher than i n the o r i g i n a l s o l u t i o n , corresponding to 0.05-0.06g nonsolvent water/g c e l l u l o s e f o r c o t t o n l i n t e r s and ramie and 0.110.13g/g f o r mercerized f i b e r s . Tankard (33) a p p l i e d t h i s method to a v a r i e t y of c e l l u l o s e f i b e r s , applying higher pressures than Champetier to reduce the amount of water a s s o c i a t e d w i t h a pressed sample as low as 0.20 g/g. His data p o i n t s r e q u i r e d s h o r t e r e x t r a p o l a t i o n to the h o r i z o n t a l a x i s (Figure 4 ) . He found some dependency of r e s u l t s upon the i n i t i a l c o n c e n t r a t i o n of the s a l t s o l u t i o n ,

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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1

but g e n e r a l l y confirmed Champetier s r e s u l t s . Values of nonsolvent water were 0.05, 0.06, 0.08, 0.11, and 0.13 g/g f o r c o t t o n , l i n e n , d r i e d mercerized c o t t o n , undried mercerized cotton, and rayon, r e s p e c t i v e l y . More r e c e n t l y , two kinds of problems have been encountered w i t h t h i s method when i t was extended to other s a l t s . (1) For the sodium c h l o r i d e - r a y o n system (34), e x t r a p o l a t e d l i n e s r e p r e s e n t i n g d i f f e r e n t i n i t i a l concentrations of s a l t i n t e r c e p t e d the h o r i z o n t a l a x i s at s u b s t a n t i a l l y d i f f e r e n t p o i n t s . (2) For other rayon systems i n v o l v i n g sodium or cadmium s u l f a t e , the p o i n t s r e p r e s e n t i n g data from d i f f e r e n t pressures and a given i n i t i a l concentrat i o n of s a l t d i d not l i e on a s t r a i g h t l i n e (34). Geiger and Nobst (34) observed t h a t v a l u e s f o r nonsolvent water v a r i e d with the e l e c t r o l y t e and i t s c o n c e n t r a t i o n , that the apparent nonsolvent water decreased w i t h i n c r e a s i n g c o n c e n t r a t i o n of the e l e c t r o l y t e , and that there was no evidence of w e l l defined hydrates of c e l l u l o s e . In 1946, Hermans (13b) reported values of nonsolvent water obtained by measuring d e n s i t i e s of c e l l u l o s e samples i n aqueous s o l u t i o n s w i t h i n c r e a s i n g concentrations o f sodium c h l o r i d e o r glucose. Values o f nonsolvent water c a l c u l a t e d f o r v a r i o u s concentrations o f s o l u t e were e x t r a p o l a t e d to zero s o l u t e c o n c e n t r a t i o n . He r e p o r t e d 0.06 and 0.10g/g c o t t o n f o r measurements i n v o l v i n g s o l u t i o n s o f sodium c h l o r i d e (mol wt 58.5) and glucose (mol wt 180), r e s p e c t i v e l y . Hermans expressed r e s e r v a t i o n s concerning the s i g n i f i c a n c e of these r e s u l t s i n view of the dependency o f the v a l u e of nonsolvent water upon molecular weight of the s o l u t e . In t h i s case, glucose was considered to be a l a r g e molecule that was r e s t r i c t e d i n p e n e t r a t i o n by i t s s i z e , whereas water molecules and common

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

2.

ROWLAND

Cellulose:

Pores, Surfaces, and

Interface

i n o r g a n i c i o n s were considered capable o f f r e e c i r c u l a t i o n i n the pores o f c e l l u l o s e f i b e r s . Barkas (35) measured s e l e c t i v e a b s o r p t i o n of water by wood from s o l u t i o n s o f sugars by u s i n g an i n t e r f e r o m e t e r to determine changes i n c o n c e n t r a t i o n . Since h i s r e s u l t s i n d i c a t e d a 3 - f o l d higher amount ( c a . 0.20g/g) o f nonsolvent water than expected, these measurements were repeated by Stamm and Hansen (36) w i t h s o l u t i o n s o f sodium c h l o r i d e , g l y c e r o l , and sucrose. T h e i r r e s u l t s showed that measurements l i k e those o f Barkas, which were conducted w i t h s o l u t e s i n concentrations that d i d not depress the r e l a t i v e vapor p r e s s u r e , do not measure the t r u e surface-bound water. By a n a l y z i n g the data i n another way, they concluded t h a t a constant v a l u e of 0.03g absorbed water/g c e l l u l o s i approached i e q u i l i b r i u with r e d u c t i o n s i n vapo Heymann and M c K i l l o p (37) i n v e s t i g a t e lyotropi s e r i e s o f s a l t s and a t t r i b u t e d n e g a t i v e values o f nonsolvent water to a b s o r p t i o n o f s a l t s , the order being CNS">l">IO«">Br"">N0 ">Cl">acetate>SO^ 3

+

+

f o r anions and

+

NH >K >Li >Na , and B a ^ C a ^ S r ^ M g * " * " f o r c a t i o n s . 4

Bien and Lindenberg (38) v a r i e d c o n c e n t r a t i o n s o f sodium t h i o s u l f a t e from 0.1242 to 682.52g/l f o r measurements of nonsolvent water. T h e i r r e s u l t s , which a r e shown by the curve i n F i g u r e 5, c o i n c i d e w i t h r e s u l t s o f Tankard (see above),

Figure 5. Non-solvent water as a function of concentration of sodium thiosulfate solutions contacted with α-cellulose. The curve is from Bien and Lindenberg (38) and the data points from Tankard (33).

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

which i n v o l v e d h i g h concentrations o f s o l u t e and which a r e designated i n the f i g u r e by c i r c l e s . A t low concentrations o f s o l u t e , nonsolvent water i n c r e a s e d r a p i d l y , w i t h decreasing s o l u t e c o n c e n t r a t i o n approaching a v a l u e o f 0.38g/g c e l l u l o s e at zero c o n c e n t r a t i o n o f s o l u t e . T h i s v a l u e i s many times higher than t h a t estimated f o r nonsolvent water and a c t u a l l y approaches t h e amount o f water r e q u i r e d t o completely s a t u r a t e the f i b e r pores. R e s u l t s summarized i n t h i s s e c t i o n i l l u s t r a t e s e v e r a l p o i n t s . E a r l y i n v e s t i g a t o r s assumed t h a t common i n o r g a n i c ions c o u l d penetrate c e l l u l o s e f i b e r s and c i r c u l a t e i n pores as f r e e l y as water, and that reasonable values f o r nonsolvent water would c o i n c i d e w i t h v a l u e s measured f o r bound water, about 0.02 t o 0.2g/g c e l l u l o s e f o r nonsolvent water wer 0.05g/g c o t t o n . However, the course o f t h i s r e s e a r c h has shown t h a t reasonable v a l u e s a r e forthcoming only w i t h c e r t a i n e l e c t r o l y t e s , t h a t r e s u l t s w i t h the most acceptable s o l u t e (sodium t h i o s u l f a t e ) a r e c o n c e n t r a t i o n dependent (a consequence o f z e t a p o t e n t i a l o r Donnan e f f e c t s ) , and t h a t many s a l t s a r e apparently adsorbed on c e l l u l o s e * The fundamental weakness o f t h i s approach f o r d i s c e r n i n g the presence o f bound water on c e l l u l o s i c s u r f a c e s l i e s i n t h e f a c t t h a t e l e c t r i c a l f o r c e s can have great i n f l u e n c e on the outcome o f r e s u l t s w i t h e l e c t r o l y t e s , and i n the f a c t t h a t the assumption concerning the f r e e access o f ions t o a l l pores t h a t a r e a v a i l a b l e to water i s i n e r r o r . I t i s n o t r e a l l y c l e a r what these e x p e r i mentally measured values represent. One v a l u e o f t h i s r e s e a r c h i s t h a t i t l e d up t o the r e s e a r c h d e s c r i b e d i n the f o l l o w i n g section. Solute E x c l u s i o n by Molecular

Size

Aggebrandt and Samuelson (39) were the f i r s t t o d e s c r i b e use o f s o l u t i o n s o f homologous s e r i e s o f polymer molecules to assess degrees o f p e n e t r a t i o n o f s o l u t e s i n t o porous c e l l u l o s i c f i b e r s . Some o f t h e i r data f o r p u r i f i e d c o t t o n and f o r p o l y n o s i c f i b e r s a r e p l o t t e d i n F i g u r e 6. Because the h i s t o r y o f the term "nonsolvent water" a s s o c i a t e s i t w i t h bound water, i t i s a p p r o p r i a t e t o modify terminology and emphasize t h a t Aggebrandt and Samuelson measured t h e amount o f water t h a t i s i n a c c e s s i b l e t o t h e i r s p e c i f i c s o l u t e s . The i n t i m a t i o n a t t h i s p o i n t i s t h a t i n a c c e s s i b l e water i s i n smaller pores than w i l l accommodate the s o l u t e , but that bound water i s n o t t o be excluded as a p o s s i b l e e x p l a n a t i o n . Curves i n F i g u r e 6 i l l u s t r a t e that the amount o f water that i s i n a c c e s s i b l e t o a s p e c i f i c s o l u t e i n c r e a s e s w i t h the molecular weight o f the s o l u t e , and t h a t i n a c c e s s i b i l i t y f o r a given s o l u t e v a r i e s w i t h the c e l l u l o s i c f i b e r . Polyethylene g l y c o l s

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

2.

ROWLAND

Cellulose:

Pores, Surfaces, and

Interface

33

Journal of Applied Polymer Science

10

100

1000 MOLECULAR

WEIGHT

_i_

10000

fibers (X —) as a function of molecular weight of each poly­ ethylene glycol used in the meas­ urement (39)

were more s u i t a b l e molecular probes than e l e c t r o l y t e s , s i n c e c o n c e n t r a t i o n had a n e g l i g i b l e e f f e c t upon the measured v a l u e f o r i n a c c e s s i b l e water i n the former case, but d i d a f f e c t values measured w i t h sodium polymetaphosphates. Tarkow and F e i s t (40) obtained data and curves g e n e r a l l y s i m i l a r i n shape to that o f the upper curve i n F i g u r e 6 by u s i n g a s e r i e s o f polyethylene g l y c o l s t o measure i n a c c e s s i b l e water i n h o l o c e l l u l o s e , cellophane, and wood. Stone and S c a l l a n (41) made e x t e n s i v e use o f s o l u t e molecules c o v e r i n g a broad range o f molecular weights t o assess i n a c c e s s i b l e water i n v a r i o u s c e l l u l o s e s . Some o f the r e s u l t s o f Stone e t a l . (42) are summarized i n F i g u r e 7. I n a c c e s s i b l e water i s p l o t t e d a g a i n s t molecular diameters o f sugars and h i g h molecular weight l i n e a r dextrans. Molecular diameters o f the s o l u t e s were c a l c u l a t e d from d i f f u s i o n c o e f f i c i e n t s according t o the E i n s t e i n - S t o k e s formula. Stone and S c a l l a n explained t h e i r r e s u l t s as those o f u s i n g f e e l e r gauges t o probe and measure pores i n the 4 t o 1000A range. I f a l l o f the water o r i g i n a l l y a s s o c i a t e d w i t h a porous body i s a c c e s s i b l e t o a s m a l l molecule, i t w i l l con­ t r i b u t e t o d i l u t i o n o f the s o l u t i o n by v i r t u e o f an i n c r e a s e d volume a v a i l a b l e t o the s o l u t e (case A, F i g u r e 8 ) . As progres­ s i v e l y l a r g e r molecules are i n v o l v e d (cases Β & C) the smaller pores and, f i n a l l y , a l l o f the pores become i n a c c e s s i b l e t o the s o l u t e molecules. Water i n the i n a c c e s s i b l e pores i s then u n a v a i l a b l e f o r d i l u t i o n o f the s o l u t e . Hence, d i f f e r e n c e s i n c o n c e n t r a t i o n must be measured w i t h h i g h accuracy, f o r which Stone and S c a l l a n employed a d i f f e r e n t i a l r e f r a c t o m e t e r . From curves such as i l l u s t r a t e d i n F i g u r e 7, i n f o r m a t i o n i s a v a i l a b l e

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

MOLECULAR WEIGHT

Tappi Figure 7. Volume of water that is inaccessible in various cellulosic substrates to molecules of increasing size. ( ) never-dried; ( ) dried and rewetted cellulose. The curve for cotton linters (43) was added to the original figure (42).

MOLECULAR DIAMETER, A

Tappi Figure 8. Illustration of the principle of solute exclusion with molecules of three sizes and pores of two sizes (42)

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

2.

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Cellulose:

Pores, Surfaces, and

Interface

35

concerning (a) t o t a l water w i t h i n the c e l l u l o s e ( i . e . , water i n a c c e s s i b l e to l a r g e s o l u t e s ) , (b) maximum pore s i z e ( i n terms of molecular diameter, F i g . 7 or molecular weight, F i g . 6), (c) median pore s i z e , and (d) a c c e s s i b l e water ( i . e . , t o t a l water of s w e l l i n g minus i n a c c e s s i b l e water). As shown i n F i g u r e 7, about 0.1-0.2 ml water/g c e l l u l o s e i s contained i n pores that are i n a c c e s s i b l e to the glucose molecule (mol wt 180). Stone et a l . (42) suggested that t h i s water was i n t e r m o l e c u l a r water r a t h e r than i n t e r f i b r i l l a r water and that p o s s i b l y i t was bound water. Jn a review paper, Boesen (31) proposed that a pore of 8 A could be spanned by j u s t 2 water molecules, which might c o n s t i t u t e the bound water t h a t would not be a v a i l a b l e f o r s o l v e n t a c t i o n . There i s , however, no experimental evidenc that h as i n Figure 7 w i l l no s i b l e water f o r s o l u t e The most recent c o n t r i b u t i o n s concerning i n t e r a c t i o n s of s o l u t e s w i t h c e l l u l o s e are described i n the work of Rowland and B e r t o n i e r e (44), who employed a g e l permeation method developed by M a r t i n et_ a l . (45)· The l a t t e r authors passed water-soluble s o l u t e s o f v a r i o u s molecular weights through columns of chopped c e l l u l o s e , measured c h a r a c t e r i s t i c s of the columns and e l u t i o n volumes of the s o l u t e s , and c a l c u l a t e d features such as e l u t i o n volumes r e l a t i v e to glucose (R ), i n t e r n a l water volume i n the c e l l u l o s e (V.), and the f r i c t i o n of i n t e r n a l water a c c e s s i b l e to the s o l u t e (A ). For a v a r i e t y of s o l u t e s on a p u r i f i e d cotton column, A i s p l o t t e d as a f u n c t i o n of molecular weight of s o l u t e i n F i g u r e 9. Data p o i n t s f o r sugars of molecular weight 180-666 (curves A and B) provide the b a s i s f o r s t r a i g h t l i n e e x t r a p o l a t i o n s to A = 1.0 a t mol wt 18. Data p o i n t s f o r polyethylene g l y c o l s of molecular weights 62-1000 (curve C) are the b a s i s f o r extrapol a t i o n of the curve to A 1.0 a t mol wt 18. The same w data are p l o t t e d as a f u n c t i o n of molecular diameter of s o l u t e s i n F i g u r e 10. Lack o f coincidence of the two curves i n t h i s f i g u r e i s b e l i e v e d to be due, i n p a r t , to approximat i o n s i n e s t i m a t i n g molecular diameters. However, curves f o r the stubby saccharide chains and f o r the slender polyethylene g l y c o l chains e x t r a p o l a t e smoothly to A = 1.0 a t molecular diameter of 4, which approximates that of the water molecule. The i m p l i c a t i o n s of the e x t r a p o l a t i o n s i n Figures 9 and 10 are t h a t , as a saccharide or g l y c o l type o f s o l u t e decreases i n molecular weight and s i z e to approach those of water, a l l of the i n t e r n a l water becomes a v a i l a b l e as s o l v e n t water. These r e s u l t s suggest t h a t the u n a v a i l a b i l i t y of i n t e r n a l water to f u n c t i o n as a solvent f o r the sugars or saccharides i s based s o l e l y on the inadequacy o f small pores to accommodate the s o l u t e , i . e . , these s o l u t e s show no evidence f o r nonsolvent water or bound water i n an a c c e s s i b l e pore. This type of behavior i s

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

°0

'

200

'

400

'

600

'

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'

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MOLECULAR WEIGHT

Figure 9. Fraction of total internal pore water that is available in chopped cotton cellulose to a solute (A ) as a function of molecular weight of the solute. Curves A and Β pertain to data from the series of sugars (glucose, maltose, raffinose, stachyose). Two separate lines are shown (line A for O ; line Β for Φ) representing the widest range of experimental data on separate series of runs. Curve C connects points for ethylene glycol and polyethylene glycols. Curve D con­ nects points for mono-, di-, tri-, and tetraglymes (44). w

, 5

1

, 10

, 20

1— *o ——— —r~

40

80

MOLECULAR DIAMETER (A)

Textile Research Journal Figure 10. Fraction of internal pore water in chopped cotton cellulose that is available to a solute (A ) as a function of logarithm of molecular diameter of the solute. Curve A refers to sugars and Β to polyethylene glycols (44). w

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

2.

ROWLAND

Cellulose:

Pores, Surfaces, and

Interface

not i n c o n s i s t e n t w i t h the e x i s t e n c e of bound water on the surface of c e l l u l o s i c p o r e s . According to the thermal expans i o n measurements of Ramiah and Goring (20) and Neal and Goring (24), glucose and v a r i o u s forms of c e l l u l o s e are capable of i n t e r a c t i n g w i t h water i n p r o p o r t i o n to t h e i r i n d i v i d u a l a c c e s s i b i l i t i e s . Therefore, i t may be expected that bound water on the s u r f a c e of c e l l u l o s e w i l l s t i l l be a v a i l a b l e as s o l v e n t water to saccharide s o l u t e s such as glucose, maltose, e t c . The s i t u a t i o n f o r p o l y e t h y l e n e g l y c o l s i s discussed below. Glymes, i . e . , methyl ethers of mono-, d i - , t r i - , and t e t r a e t h y l e n e g l y c o l s , were e l u t e d from p u r i f i e d chopped cotton columns (see F i g . 9, curve D) as i f t h e i r molecular diameters were l a r g e r o than those of polyethylen weight. Others (41, 46) have e s t a b l i s h e d that n e i t h e r p o l y ethylene g l y c o l s nor sugars (or dextrans) show evidence of s o r p t i o n on c e l l u l o s e . An a l t e r n a t e and more p l a u s i b l e explanation i s that glymes, having no f r e e hydroxyl groups, are l e s s capable than g l y c o l s of d i s r u p t i n g bound water a t the surfaces of c e l l u l o s i c pores. With l e s s than a l l the water i n each pore a v a i l a b l e as s o l v e n t , the r e s u l t i s that of smaller e f f e c t i v e pores f o r the glymes. Because the higher g l y c o l s have decreasing donor-hydrogen bonding c a p a c i t y ( i . e . , p r o ceeding from ethylene g l y c o l to d i - , t r i - , and polyethylene g l y c o l s ) , i t i s expected that the c a p a b i l i t y of g l y c o l s to u t i l i z e water at the s u r f a c e of c e l l u l o s e as s o l v e n t decreases with i n c r e a s i n g molecular weight. Thus, as molecular weight of polyethylene g l y c o l s i n c r e a s e s from that of ethylene g l y c o l , i t i s proposed that the s o l u t e confronts an i n c r e a s i n g s h e l l of bound or nonsolvent water a t the c e l l u l o s e - w a t e r interface. For information concerning s o r p t i o n of s m a l l molecules on c e l l u l o s i c s u r f a c e s , Rowland and B e r t o n i e r e (44) showed that patterns of e l u t i o n of s o l u t e s were s i m i l a r from columns of chopped c o t t o n and from Sephadex G-15 (a c r o s s l i n k e d dextran)· They s t u d i e d e l u t i o n of s o l u t e s from the l a t t e r column because d i f f e r e n c e s i n e l u t i o n volumes were l a r g e r and could be measured more p r e c i s e l y on t h i s column. The norm, which was taken as the b a s i s f o r d i s c r i m i n a t i n g between s o r p t i o n and r e p u l s i o n , was the e l u t i o n of h y d r o x y l i c compounds, s p e c i f i c a l l y the l i n e from methanol (M) to ethylene g l y c o l (EG) to glucose (GL) i n F i g u r e 11. R values ( e l u t i o n volume of s o l u t e r e l a t i v e to that of glucose)^higher than those of the r e f e r e n c e l i n e were taken to i n d i c a t e p o s i t i v e s o r p t i o n and lower values to i n d i c a t e negative s o r p t i o n or r e p u l s i o n from the h y d r o x y l i c p o l y s a c c h a r i d i c s u r f a c e s . Strong s o r p t i o n was found f o r polyamines, ethylenediamine (ETA) and d i e t h y l e n e t r i a m i n e

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

38

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

MOLECULAR WEIGHT 0

50

100

11

CH2OCH3

12

CH 0H 2

CH OCH 2

3

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13

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14

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15

CH2OCH3

CH OCH

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.

Textile Research Journal Figure 11. Elution volumes from a Sephadex G-15 column for various solutes relative to the elution volume of glucose (R ) plotted as a function of molecular weight. M = methanol, EG = ethylene glycol, GL = glucose, MG = methyl glucuronate, CA = glucuronic acid, EDA = ethylene diamine, DETA = diethylenetriamine, D = methylenebis-l-[3-methyl-(2-imidazolidinone]. Imidazolidinones are identified in the tabulation and designated by numbers in the plot (44). g

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

2.

ROWLAND

Cellulose:

Pores, Surfaces, and

Interface

(DETA)· P r o g r e s s i v e l y decreasing s o r p t i o n occurred f o r imidazolidinones having (a) one f r e e proton on each amide n i t r o g e n (data p o i n t s 1-4), (b) a s i n g l e f r e e proton between two amide nitrogens (data p o i n t s 5 and 6 ) , and (c) no f r e e protons on amide n i t r o g e n s (data p o i n t s 7-12-D). The decrease i n s o r p t i o n i s p a r a l l e l to decreasing a b i l i t y of the s o l u t e to hydrogen-bond to the hydroxyl groups of Sephadex. I n t r o d u c t i o n of methyl groups onto r i n g hydroxyls of imidazolidinones (data p o i n t s 8, 13-15) and glucose (PMG, pentamethyl glucose) reduced R more than expected f o r the i n c r e a s e o f molecular weight, I n e f f e c t t h a t f a l l s i n l i n e with that observed between glymes and g l y c o l s . A carboxyl group at C(6) i n glucose caused negative s o r p t i o n , as i n d i cated by a comparison o glucose (GL), and methy I t i s evident from r e s u l t s summarized i n t h i s s e c t i o n that the primary f a c t o r c o n t r o l l i n g p e n e t r a t i o n of a s o l u t e i n aqueous s o l u t i o n i n t o c e l l u l o s i c pores i s a s i e v i n g a c t i o n , i . e . , d i s c r i m i n a t i o n on the b a s i s o f molecular s i z e . But a secondary e f f e c t , which can be q u i t e l a r g e , depends upon the a b i l i t y of the s o l u t e to d i s r u p t bound water a t the c e l l u l o s e water i n t e r f a c e so t h a t i t becomes a v a i l a b l e as s o l v e n t . A l l water i n a c c e s s i b l e pores of cotton c e l l u l o s e appears to be a v a i l a b l e as s o l v e n t water to saccharides and other s o l u t e s having high p r o p o r t i o n s of groups capable of strong donor and acceptor hydrogen bonding. Water-soluble s o l u t e s that are c h a r a c t e r i z e d by l i m i t e d hydrogen bonding i n comparison to saccharides f i n d that only a f r a c t i o n of the t o t a l water i n an a c c e s s i b l e pore i s a v a i l a b l e as s o l v e n t . Solutes t h a t form stronger donor and acceptor hydrogen bonds than are formed by saccharides e v i d e n t l y f i n d a l l water i n an a c c e s s i b l e pore a v a i l a b l e as s o l v e n t ; furthermore, these s o l u t e s i n t e r a c t w i t h c e l l u l o s i c and p o l y s a c c h a r i d e s u r f a c e s i n p r o p o r t i o n to the s t r e n g t h and number o f hydrogen bonds that may be formed. Permeation of water-soluble s o l u t e s i n c e l l u l o s i c pores i s i n f l u e n c e d by e l e c t r o s t a t i c charge, w i t h c a t i o n i c and a n i o n i c charges c o n t r i b u t i n g to p o s i t i v e and negative s o r p t i o n , respectively. S t r u c t u r e of Water near P o l a r

Surfaces.

L i q u i d water possesses d i s t i n c t i v e s t r u c t u r a l features that are a t t r i b u t a b l e to r e t e n t i o n of a l a r g e degree of i c e - l i k e - n e s s . In 1933, Bernai and Fowler (47) proposed that the long range hydrogen-bonding order o f i c e s was broken when i t melted, that the l i q u i d s t i l l r e t a i n e d a h i g h degree of short range order, and t h a t ions i n c r e a s e d or decreased i n t e r n a l coherence and r e g u l a r i t y of s t r u c t u r e . In 1957, Frank and Wen (23) suggested that water c o n s i s t s of f l i c k e r i n g

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

40

c l u s t e r s o f hydrogen-bonded molecules i n which the i c e - l i k e - n e s s i s the r e s u l t of a cooperative phenomenon. That i s , when one hydrogen bond between molecules forms, s e v e r a l o r many bonds form to make a c h a i n o r c l u s t e r , and when one bond breaks i n the c h a i n , the whole c l u s t e r breaks o r d i s s o l v e s . At one i n s t a n t there e x i s t s a m a t r i x o r s o l u t i o n i n which i c e - l i k e c l u s t e r s a r e d i s t r i b u t e d i n unbonded water molecules. Nemethy and Scheraga (21) expanded t h i s theory and t r e a t e d i t q u a n t i t a t i v e l y , c o n s i d e r i n g that the s i z e and extent of c l u s t e r i n g decreased w i t h i n c r e a s i n g temperature and that c l u s t e r s continuously^gormed a j ^ disappeared, w i t h an average l i f e t i m e of about 10 t o 10~ s e c . They c a l c u l a t e d t h a t , on average, a c l u s t e r contains 57 molecules o f water a t 20°C and 21 molecules a t 100°C (21) d that t give i n s t a n t 70% of the water molecules Although there a r e othe , t h i s f l i c k e r i n g c l u s t e r theory i s the most widely accepted. Goring (22) d i s c u s s e d the e f f e c t o f c e l l u l o s e and other wood c o n s t i t u e n t s on the s t r u c t u r e o f water and proposed that carbohydrate s u r f a c e s perturb the l a y e r o f water next to the surface i n such a way that c l u s t e r i n g i s diminished, a concept that has a l r e a d y been i l l u s t r a t e d i n F i g u r e 3· He v i s u a l i z e d that hydroxy1 groups on the carbohydrate l a c k the s p a t i a l symmetry found i n the water molecules; hence, they cannot g e n e r a l l y become p a r t o f a c l u s t e r , and the v i c i n a l l a y e r o f water i s perturbed to c o n t a i n a h i g h p r o p o r t i o n o f u n c l u s t e r e d water molecules. Drost-Hansen (49) made an e x t e n s i v e review of i n f o r m a t i o n concerning the nature o f w a t e r - s o l i d i n t e r f a c e s and p o s t u l a t e d a 3-layer model f o r the s t r u c t u r e o f water near p o l a r s u r f a c e s . F i g u r e 12 shows t h i s model. Molecules

Industrial and Engineering Chemistry Figure 12. Model for the structure of water near polar surfaces

m

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

2.

ROWLAND

Cellulose:

Pores, Surfaces, and

Interface

41

immediately adjacent t o the p o l a r s u r f a c e a r e o r i e n t e d by d i p o l e d i p o l e i n t e r a c t i o n , t h i s type o f order p o s s i b l y extending over a few molecular diameters. The second zone o r l a y e r represents a d i s o r d e r e d t r a n s i t i o n between ordered v i c i n a l water s t r u c t u r e and bulk water. A t h i r d l a y e r i s that of bulk water, i n which the pentagonal c i r c u i t s and p a r t i a l pentagonal o u t l i n e s a r e intended to convey only the presence of g e o m e t r i c a l l y i d e n t i f i a b l e s t r u c t u r a l e n t i t i e s ( c l u s t e r s ) which f l i c k e r i n t o and out o f e x i s t e n c e throughout the bulk phase. This model d i f f e r s from that proposed by Goring (22) and i l l u s t r a t e d i n F i g u r e 3 i n that i t introduces a l a y e r of o r i e n t e d or s t r u c t u r e d water molecules on the p o l a r s u r f a c e . Drost-Hansen s model f o r the s t r u c t u r e o f water near the surface o f a p o l a r s o l i d bear similarit t th s t r u c t u r of water about ions havin 50). Such i o n s a r e surrounde y region water, the former r e f e r r i n g to the h i g h l y s t r u c t u r e d , immobil i z e d water i n the primary h y d r a t i o n sphere immediately adjacent to the i o n , and the l a t t e r t o randomly o r i e n t e d water that i s f a r t h e r from the nucleus and i s not i n v o l v e d i n c l u s t e r formation. This composite i s surrounded by normal bulk water. At l e a s t two questions a r i s e i n c o n s i d e r a t i o n o f these two and other models (51) f o r the w a t e r - c e l l u l o s e i n t e r f a c e . The f i r s t question concerns the a b i l i t y o f the h y d r o x y l i c surface o f a carbohydrate, whether i n water s o l u t i o n or an i n s o l u b l e i n t e r f a c e , t o p o l a r i z e o r hydrogen-bond water molecules i n t o a l a y e r corresponding t o the ordered v i c i n a l l a y e r i n Drost-Hansen s model o r the "A" r e g i o n o f an i o n . G o r i n g s model does not i n c l u d e t h i s l a y e r , but d e p i c t s the surface of a carbohydrate as g e n e r a l l y s i m i l a r t o the s u r f a c e of the l a y e r o f immobilized water ("A" region) on the i o n (52). The second question r e l a t e s t o the nature, p r i m a r i l y the m o b i l i t y , o f the water molecules i n the disordered t r a n s i t i o n l a y e r (zone 2) o f Drost-Hansen's model, the perturbed s u r f a c e l a y e r o f G o r i n g s model, and the "B" r e g i o n o f i o n s . Dobbins (51) r e f e r s t o the "B" s h e l l o f water molecules as being very f l u i d , mobile water. Y e t , current i n d i c a t i o n s a r e that the perturbed l a y e r measured by Neal and Goring (24) i s the same as, o r p o s s i b l y a p a r t o f the bound water measured by other techniques. f

f

1

1

Whichever model proves t o d e s c r i b e the water-carbohydrate surface most a c c u r a t e l y , i t i s reasonable t o expect a gross s i m i l a r i t y i n the i n t e r a c t i o n between water and c e l l u l o s e a t the l i q u i d - s o l i d i n t e r f a c e and between water and a s o l u b l e saccharide such as glucose. This being the case, i t may be a n t i c i p a t e d that there w i l l be no evidence f o r bound water as a r e s u l t o f i n t e r a c t i o n o f a water-soluble s o l u t e with c e l l u l o s i c surfaces when the s o l u t e and the s u r f a c e a r e capable

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

of equal i n t e r a c t i o n s w i t h water. On the other hand, evidence f o r bound water may be expected when t h e s o l u t e i s l e s s capable o f competing w i t h the s o l i d i n t h e i n t e r f a c e f o r the s t r u c t u r i n g o f water. Conclusions This r e p o r t has undertaken to review the i n t e r a c t i o n o f water w i t h c e l l u l o s i c surfaces and to develop t o the extent that i s reasonable a t t h i s time an o v e r a l l p e r s p e c t i v e concerning the c e l l u l o s e - w a t e r i n t e r f a c e . I n an area such as t h i s i n which the s t r u c t u r e o f water i s s t i l l open t o v a r i o u s i n t e r p r e t a t i o n s and concepts (49) and the p r e c i s e nature o f a c c e s s i b l e s u r f a c e s o f c e l l u l o s ha onl bee touched i recent years (29,30), an t i v e borders on pure s p e c u l a t i o n , merit i n t a k i n g a broad view o f t h i s f i e l d w i t h the purpose o f b u i l d i n g on the c o n s i s t e n c i e s t h a t e x i s t . In t h i s l i g h t , t e n t a t i v e c o n c l u s i o n s and o v e r a l l p e r s p e c t i v e s a r e o f f e r e d as p o i n t s f o r v e r i f i c a t i o n and departure. A network o f channels and pores i s b u i l t i n t o c e l l u l o s e at the time the s o l i d s u b s t r a t e i s generated, i . e . , growth i n the case o f a n a t u r a l f i b e r o r e x t r u s i o n i n the case o f a man-made product. On d r y i n g , the channels and pores c o l l a p s e i n p r o p o r t i o n t o t h e extent o f d e s i c c a t i o n ; some empty spaces remain adjacent t o the s u r f a c e s o f m i c r o s t r u c t u r a l elements that a r e most s t r a i n e d and on which the I)-glucopyranosyl u n i t s (and h y d r o x y l groups) are most h i g h l y d i s r u p t e d from p e r f e c t alignment and l a t e r a l order. I t i s these extremely s m a l l pores i n t o which water, but n o t n i t r o g e n , may be able to f i l t e r w i t h minimum need t o break i n t e r m o l e c u l a r hydrogen bonds i n the c e l l u l o s e . Hydrogen bonding of f r e e water molecules on these s u r f a c e s could generate the maximum heat e f f e c t (5 kcal/mol) and the minimum change i n f i b e r s i z e o r apparent d e n s i t y . Throughout t h i s e a r l y stage o f h y d r a t i o n o f c e l l u l o s e , and p o s s i b l y c o n t i n u i n g i n t o l a t e r stages, the r e l e a s e o f s t r a i n i n m i c r o s t r u c t u r a l elements c o n t r i b u t e s t o the heat o f i n t e r a c t i o n o f c e l l u l o s e with water. T h i s heat of i n t e r a c t i o n must be m o d i f i e d by other e f f e c t s such as that f o r breaking c e l l u l o s e - c e l l u l o s e hydrogen bonds and that f o r expanding the i n t e r f i b r i l l a r pores. At l e a s t f o r t h e n a t i v e c o t t o n f i b e r , t h e r e i s evidence f o r two q u i t e d i f f e r e n t types o f a c c e s s i b l e s u r f a c e s : one having a higher p o p u l a t i o n o f f r e e ( i . e . , n o n i n t e r - o r i n t r amolecular bonded) hydroxyl groups p e r u n i t o f s u r f a c e and being l e s s o r d e r l y a s s o c i a t e d w i t h adjacent s u r f a c e s , and the other having q u i t e h i g h l y ordered hydrogen bonded hydroxyl groups and being q u i t e w e l l a s s o c i a t e d w i t h adjacent l a t e r a l s u r f a c e s . Both these types o f s u r f a c e s may be considered

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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Cellulose:

Pores, Surfaces, and

Interface

43

p o l a r and capable of i n t e r a c t i o n w i t h water. However, they d i f f e r i n the extreme by having as many as three f r e e hydroxyl groups f o r donor and acceptor hydrogen bonding on the one hand, and by having l i t t l e more than one f r e e hydroxyl group f o r donor and acceptor bonding p l u s two h y d r o x y l i c oxygens (already i n t e r n a l l y hydrogen bonded) a v a i l a b l e only as acceptors. Chemical evidence f o r the two types of s u r f a c e s shows a sharp demarcation between the two, y e t i t i s not u n l i k e l y t h a t other means f o r sensing these two types o f surfaces may be l e s s c l e a n c u t . Measurements of f r e e z i n g and nonfreezing water by c a l o r i m e t r i c or NMR methods appear to d e t e c t two degrees of strong a s s o c i a t i o n of water w i t h c e l l u l o s i c s u r f a c e s , but more q u a n t i t a t i v e data are needed. P e n e t r a t i o n of a water-solubl or p o l y s a c c h a r i d i c por r e l a t i v e to the s i z e o f the s o l u t e . In the case of l i n e a r molecules, the s i z e of the s o l u t e must be the consequence of a random c o i l . A s s o c i a t i o n of water a t the c e l l u l o s e - w a t e r i n t e r f a c e reduces the e f f e c t i v e volume of a ppre or a channel, and hence allows a smaller volume a v a i l a b l e to a s o l u t e unless that s o l u t e i s capable o f d i s r u p t i n g t h i s a s s o c i a t i o n . This being the mechanism of p e n e t r a t i o n of a water-soluble s o l u t e , the primary c o n t r o l l i n g f a c t o r i s the d i s t r i b u t i o n of pore s i z e s i n the s u b s t r a t e . The secondary f a c t o r i s a dependency upon the s o l u t e and r e l a t e s to i t s a b i l i t y to i n t e r a c t s t r o n g l y with bound water a t the w a t e r - c e l l u l o s e i n t e r f a c e . The r e s u l t of o p e r a t i o n of these two f a c t o r s i s t h a t f o r s o l u t e s there i s not a unique amount of bound water on a c e l l u l o s i c or p o l y s a c c h a r i d i c s u r f a c e , but, r a t h e r , each s o l u t e w i l l sense or confront an amount of bound water t h a t i n c r e a s e s i n i n v e r s e p r o p o r t i o n to the c a p a b i l i t y of the s o l u t e to i n t e r a c t w i t h water by the same mechanism. Much a d d i t i o n a l q u a n t i t a t i v e i n f o r m a t i o n i s needed to c l a r i f y the nature of bound water on c e l l u l o s e , v a l i d i t y or meaning of measurements of bound water obtained by the v a r i o u s methods, and v a r i a t i o n s i n bound water as a f u n c t i o n of type of c e l l u l o s i c s u r f a c e .

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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Literature Cited 1·

2. 3. 4. 5. 6. 7.

8. 9. 10. 11. 12. 13.

14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24.

Valko, Ε. I., i n "Chemical Aftertreatment of Textiles," (a) PP. 6-8, (b) Tables II and I I I , (c) pp. 50-53, WileyInterscience, New York, 1971. Porter, B. R . , Crr, R. S., Text. Res. J. (1965) 35, 159. Hunt, C. Μ., Blaine, R. L., Rowan, J., J. Res. Natl. Bur. Stand. (1949) 43, 547. F o r z i a t i , F . Η . , Brownell, R. Μ., Hunt, C. M . , J. Res. Natl. Bur. Stand. (1953) 50, 139. Klenkova, Ν. I., Ivaskin, G. P., J. Appl. Chem. USSR (1963) 36, 378. Porter, B. R . , Rollins M L., J. Appl Polym S c i (1972) 16, 217. Stone, J. Ε., Scallan, Α. Μ., i n "Consolidation of the Paper Web," V o l . 1, pp. 145-166, Br. Pap. and Board Makers' Assoc. I n c . , London, 1967. Rowland, S. P. i n "Recent Advances i n Fibre Science," V o l . I I , Academic Press, London, i n press. F i l b y , A. E., Maass, O., Can. J. Res. (1932) 7, 162. Stamm, A. J., Loughborough, W. K., J. Phys. Chem. (1934) 39, 121. Magne, F. C., Portas, H. J., Wakeham, H. J., J. Am. Chem. Soc. (1947) 69, 1896. Magne, F . C., Skau, E . L., Text. Res. J. (1952) 22, 748. Hermans, P. H., "Contribution to the Physics of Cellulose Fibres," (a) pp. 73-89, (b) pp. 103-106, Elsevier, Amsterdam, 1946. Meredith, R . , i n "Moisture i n Textiles," pp. 141-159, Interscience, New York, 1960. Rees, W. H., J. Text. Inst. (1948) 39, T351. Guthrie, J. C., J. Text. Inst. (1949) 40, T489. Rees, W. Η . , i n "Moisture i n Textiles," pp. 51-58, Interscience, New York, 1960. Morrison, J. L., Dzieciuch, Μ. Α., Can. J. Chem. (1959) 37, 1379. Iyer, S. R. S., Baddi, N. T., C e l l u l . Chem. Technol. (1969) 3, 561. Ramiah, M. V., Goring, D. A. I., J. Polym. S c i . Part C (1965) 11, 27. Nemethy, G . , Scheraga, Η. Α., J. Chem. Phys. (1962) 36, 3382. Goring, D. A. I., Pulp Pap. Mag. Can. (1966) 67. (11), T159. Frank, H. S., Wen. W.-Y., Discuss. Faraday Soc. (1957) 24, 133. Neal, J. L., Goring, D. A. I., J. Polym. S c i . Part C (1969) 28, 103.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

2. ROWLAND 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43.

44. 45. 46. 47. 48. 49. 50. 51. 52.

Cellulose: Pores, Surfaces, and Interface

45

Ogiwara, Y., Kobute, M., Hayoshi, S., Mitomo, N. J . Appl. Polym. Sci. (1969) 13, 1689; ibid. (1970) 14, 303. Child, T. S., Polymer (1972) 13, 259. Carles, J . Ε., Scallan, A. M., J . Appl. Polym. Sci. (1973) 17, 1855. Friox, M. F . , Nelson, R., Macromolecules (1975) 8, 726. Roberts, E. J., Rowland, S. P., Text. Res. J . (1972) 42, 217. Rowland, S. P., Roberts, E. J., J . Polym. Sci. A-l (1972) 10, 2447. Boesen, C. E . , Cellul. Chem. Technol. (1970) 4, 149. Champetier, G., C. R. Hebd. Seances Acad. Sci. (1932) 195 280.; Ann. Chim. (Paris) (1933) [10] 20, 5. Tankard, J., J . Text. Inst. (1937) 28, T263. Geiger, E . , Nobst Η. Helv Chim Act (1961) 44 1724 Barkas, W. W., Proc Stamm, A. J., Hansen, L. Α., J. Phys. Chem. (1938) 42, 209. Heymann, Ε., McKillop, G. C., J . Phys. Chem. (1941) 45, 195. Bien, D. V., Lindenberg, A. B., C. R. Hebd. Seances Acad. Sci. (1963) 257 (16) 2283. Aggebrandt, L. G., Samuelson, O., J . Appl. Polym. Sci. (1964) 8, 2801. Tarkow, H., Feist, W. C., Tappi (1968) 51, (2) 80. Stone, J . E . , Scallan, Α. Μ., Cellul. Chem. Technol. (1968) 2 343. Stone, J . E . , Treiber, E . , Abrahamson, Β., Tappi (1969) 52, (1), 108. Stone, J . Ε., Scallan, A. M., Donesor, E . , Ahlgreen, Ε., in "Cellulases and their Application" pp. 219-241, Advan. Chem. Ser. No. 95, Amer. Chem. Soc., Washington, D. C., 1969. Rowland, S. P., Pertoniere, N. R., Text. Res. J., (1976) 46, 770. Martin, L. F . , Blouin, F. Α., Bertoniere, N. R., Rowland, S. P., Tappi (1969) 54 708. Nelson, R., Oliver, D. W., J . Polym. Sci., Part C (1971) 36, 305. Bernai, J . D., Fowler, R. H., J . Chem. Phys. (1933) 1, 515. Nemethy, G., Scheraga, Η. Α., J. Phys. Chem. (1962) 66, 1773. Drost-Hansen, W., Ind. Eng. Chem. (1969) 61 (11), 10. Franks, F . , Chem. Ind. (London) (1968) 560. Dobbins, R. J., Tappi (1970) 53, (12), 2284. Goring, D. A. I., private communication.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

3 Copolymerization of V i n y l Monomers with Cotton Studied by Electron Spin Resonance Spectroscopy OSCAR HINOJOSA Southern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, New Orleans, LA 70179

Electron spin resonanc free radicals generate have been previously made to determine the type of free radicals produced (1,2). Studies to determine the effects of solvents on the trapped radicals in γ-irradiated cotton cellulose have also been carried out (3,4). Short-lived free radicals such as those generated during polymerization and graft copolymerization reac­ tions were also investigated using special techniques and condi­ tions for trapping and detection by ESR (5-10). ESR investigations of cellulosic free radicals, propagating radicals in polymerization reactions, and free radical initiated grafting reactions with cotton cellulose are summarized in this paper. Free Radical Formation Production of free radicals in the solid state and in systems which may be frozen during the course of the reaction allows detection of trapped radicals by ESR (1,5). Although free radicals trapped in the solid state at low temperatures generally exhibit a diffuse hyperfine structure (hfs), some information about their structure may be obtained from such ESR spectra (2). Additional information about stability and struc­ ture of free radicals trapped in the solid state may be obtained by monitoring changes in hyperfine structure and intensity of ESR spectra as the system is subjected to changes in temperature or exposed to solvents (7-10). 60

Co γ-Radiation Initiation. Of the free radical generating ggstems used to produce free radicals in cotton cellulose, Co γ-radiation yielded the^greatest number of stable free radicals. Stability of the Co γ-radiation generated free radicals in cotton cellulose is due to high crystallinity of

46

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

3. HiNOjosA

Copolymerization

of Vinyl

Monomers

with

Cotton

cellulose (1). In dry cellulose, the amorphous fraction of the celluJLgsic structure traps a large number of radicals. Co γ-Radiation generates free radicals throughout the cotton cellulose matrix, i . e . , radicals are produced i n both the amorphous and crystalline regions. Radicals trapped i n the crystalline regions are inaccessible to water and may remain trapped for years under ambient conditions of temperature and humidity (11). Trapped radical spectra of cotton celluloses I and II, predried and irradiated i n a nitrogen atmosphere, are almost identical (Figure 1). Most of the free radicals formed i n the irradiated celluloses were trapped i n the accessible or less ordered regions of the c e l l u l o s i c structures (3). About 80% of the radicals formed i those formed i n irradiate lose) were scavenged by contacting the samples with water (Figure 2). Decay of free radicals i n the irradiated celluloses i n pure methanol was less than i n water. About 60% of the radicals formed i n irradiated cellulose I and only about 5% of those formed i n irradiated cellulose I I were scavenged by contacting the samples with methanol for 30 sec (Figure 3)· When a methanol (75 vol-%)-water (25 vol-%) solution was used, free radical decay took place i n cellulose I I to the same extent as i n c e l l u ­ lose I (12). Dipolar aprotic solvents also terminated free radicals i n γ-irradiated cellulose, but at a much slower rate than methanol and water (4). The apparent rates of diffusion into cellulose I were dimethyl sulfoxide > dimethylformamide > acetonitrile. When water, comprising less than 50 vol-%, was added to the d i ­ polar aprotic solvents noted above, the relative rates of d i f ­ fusion were acetonitrile-water dimethyl sulfoxide-water, dimethylformamide-water. P^eversal i n diffusion rates of the pure solvents compared with the water-solvent combinations may reflect differences i n the intramolecular association (solvation) for each of the solvents with water. Photοinitiation. Irradiation of predried, purified cotton cellulose I with light from a Rayonet Photochemical Reactor* with 90% of the radiant energy output i n the 3500 Â range resulted i n formation of free radicals which generated singlet type ESR spectra. When the cellulose was irradiated wet with water, or subsequently wet after irradiation, no detectable ESR signal was generated (14). Formation of free radicals i n light-irradiated cellulose appears to take place only i n the amorphous regions; no ESR detectable signal remains after contacting the irradiated sample with water.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

48

TEXTILE

A N D PAPER

CHEMISTRY

A N D

TECHNOLOGY

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

3.

HiNojosA

Copolymerization

of Vinyl

Monomers

with

49

Cotton

Celluloses photosensitized with f e r r i c chloride, i r r a d i a t e d at l i q u i d n i t r o g e n temperature w i t h l i g h t from a high-pressure mercury lamp, generated complex ESR s p e c t r a which have been r e ­ solved as combinations of s i n g l e - l i n e , two-line, and t h r e e - l i n e s p e c t r a (14). The r a d i c a l y i e l d i n p h o t o s e n s i t i z e d rayon c e l l u ­ l o s e , upon i r r a d i a t i o n , was about 10 times t h a t of i r r a d i a t e d , untreated rayon c e l l u l o s e (14). ESR i n v e s t i g a t i o n s of f r e e r a d i c a l s generated i n r i g i d glasses o f a l c o h o l s p h o t o s e n s i t i z e d w i t h f e r r i c c h l o r i d e have been c a r r i e d out a t near l i q u i d n i t r o g e n temperatures (7,15)· The ESR s p e c t r a generated i n each of the r i g i d g l a s s e s of a l c o h o l p h o t o s e n s i t i z e d w i t h f e r r i c c h l o r i d e have been c a r r i e d out a t near l i q u i d n i t r o g e n temperatures (7,15). The ESR s p e c t r a gene­ r a t e d i n each o f the r i g i intensity after photolysi the r i g i d g l a s s e s of a l c o h o l was i n c r e a s e d , the i n t e n s i t y of the ESR s p e c t r a continued to r i s e u n t i l r a d i c a l recombination became the predominant r e a c t i o n . Free r a d i c a l s generated i n the p h o t o s e n s i t i z e d a l c o h o l s were used to i n i t i a t e p o l y m e r i z a t i o n r e a c t i o n s of v i n y l monomers. Propagating r a d i c a l s i n the alcohol-monomer p h o t o s e n s i t i z e d system were i n v e s t i g a t e d by ESR (8,10). Hydroxyl R a d i c a l I n i t i a t i o n . Hydroxyl r a d i c a l s generated by the ¥e^/UJ^2 (16,17,18) have been used to gene­ r a t e f r e e r a d i c a l s i n c o t t o n c e l l u l o s e ( 5 ) . The c e l l u l o s e was immersed i n a 0.01 M ^eSO^ s o l u t i o n and d r i e d i n a stream of dry n i t r o g e n . The Fe impregnated d r i e d c e l l u l o s e was placed i n a quartz sample tube, 0.3 M &2°2 H ~" l o s e , and immediately l i q u i d n i t r o g e n was drawn through the wet sample. A t r i p l e t ESR spectrum was generated by the f r e e r a d i ­ c a l s trapped i n the c e l l u l o s e - i c e matrix at -110°C (Figure 4)· The f r e e r a d i c a l s were unstable and decayed beyond d e t e c t ­ able l i m i t s a t temperatures as low as -60°C. The t r i p l e t spec­ trum was a t t r i b u t e d to f r e e r a d i c a l s formed on the c e l l u l o s e when hydrogen atoms were e x t r a c t e d by hydroxyl r a d i c a l s which were produced by the r e a c t i o n (16,17,18) s

v

s

t

e

m

w

H 0 2

Polymerization

4

2

1

+ Fe "" "

a

OH"

s

d

r

a

w

n

o

n

t

o

t

h

e

c e

u

4

+ .OH + Fe"***"

Reactions

^ C o γ-Radiation I n i t i a t i o n . G r a f t i n g of m e t h a c r y l i c a c i d (MAA) onto γ-irradiated c o t t o n c e l l u l o s e proceeded r a p i d l y from water s o l u t i o n s of the monomer (19)• Cotton c e l l u l o s e yarn w h i c h ^ a d been i r r a d i a t e d i n the dry s t a t e to a 1 megarad dose with Co γ-radiation was r e a c t e d w i t h aqueous MAA (30 v o l - % ) s o l u t i o n f o r 3 min a t 25°C ( 6 ) . The unreacted monomer was

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

50

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY 100

20

40 60 80 MeOH IN H 0 . V O L - %

100

2

Figure S. Effect of methanol-water solution on the concentration of free radicals in irradiated celluloses I and II after immersion for 30 sec at 25°C. Concentration determined at -150°C.

Figure 4. ESR spectra of free radicals generated in cellulose I by the Fe /H 0 system, recorded at —110°C. Magnetic field sweep, 100 gauss, left to right. +2

2

2

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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51

removed by washing w i t h deaerated water, exchanging w i t h acetone, and d r y i n g i n a n i t r o g e n atmosphere a t 25 °C. A f t e r r e c o r d i n g ESR s p e c t r a of the d i r e d cellulose-MAA copolymer, the sample was washed w i t h aerated water, again exchanged w i t h acetone, and d r i e d w i t h n i t r o g e n a t 25°C. A t y p i c a l ESR spectrum o f d r i e d c e l l u l o s e I , i r r a d i a t e d i n n i t r o g e n , i s shown i n F i g u r e 5Α· The ESR spectrum of the c e l l u ­ l o s e copolymer, washed i n deaerated water, c o n s i s t e d of two s e t s of l i n e s (Figure 5B), one due t o c e l l u l o s i c f r e e r a d i c a l s which were not a c c e s s i b l e to the s o l v e n t s , the other due to the propa­ gating r a d i c a l o f MAA. The ESR spectrum o f the copolymer washed with aerated water, F i g u r e 5C, was i d e n t i c a l to that generated by trapped c e l l u l o s i c r a d i c a l s i n i r r a d i a t e d c e l l u l o s e which had been t r e a t e d w i t h wate (methacrylic a c i d ) r a d i c a time-averaging computer attachment, the ESR spectrum C i n F i g u r e 5 was subtracted from t h a t of Β to o b t a i n the one i n D. The ESR spectrum of the f r e e r a d i c a l s i n the copolymer scavenged by oxygen (Figure 5D) was almost i d e n t i c a l to t h a t reported by Abraham e t a l . (20) f o r γ-irradiated polymethyl methacrylate. The s e t o f f i v e l i n e s which dominates the spectrum i n F i g u r e 5D i n d i c a t e s t h a t , as w i t h l a u r y l methacrylate and methacrylamide propagating r a d i c a l s ( 8 ) , the r a d i c a l

H - C - C -C00H

e x i s t s i n the copolymer i n the s t r u c t u r a l conformation, a l l o w i n g only one o f the methylene hydrogens t o i n t e r a c t s t r o n g l y with the unpaired e l e c t r o n . Only t r a c e s o f the f o u r - l i n e spectrum were evident i n the ESR spectrum o f F i g u r e 5D. E a r l i e r ESR i n v e s t i g a t i o n s on the e f f e c t s of s o l v e n t s on trapped c e l l u l o s i c r a d i c a l s a r e c i t e d i n t h i s paper (3,4,12). The e f f e c t s o f methanol-water s o l u t i o n s on the f r e e r a d i c a l s trapped i n γ-irradiated cotton c e l l u l o s e I and I I were of p a r t i ­ c u l a r i n t e r e s t because data obtained by e l e c t r o n s p i n resonance c o r r e l a t e d w e l l w i t h t h a t from g r a f t i n g s t u d i e s (12). F i g u r e 3 shows the e f f e c t s o f methanol-water s o l u t i o n s on the extent o f f r e e r a d i c a l decay i n γ-irradiated cotton c e l l u l o s e I and I I , whereas Figure 6 shows the e f f e c t s o f these s o l u t i o n s on the extent o f g r a f t i n g o f e t h y l a c r y l a t e (9 v o l - % ) onto s i m i l a r samples a f t e r 60 min a t 25°C. From water, the extent of g r a f t i n g was greater w i t h c e l l u l o s e I than w i t h c e l l u l o s e I I , although the extent of f r e e r a d i c a l decay was l e s s i n c e l l u l o s e I . From methanol the extent o f g r a f t i n g was greater w i t h c e l l u l o s e I I than I , and f r e e r a d i c a l decay i n c e l l u l o s e I I was l e s s than i n I .

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

Figure 5. ESR spectra of free radicals generated in the methacrylic acid-y-irradiated cellulose I grafting system. (A) Irradiated, predried cellulose I; (B) cellulose-poly(methacrylic acid) copolymer; (C) cellulose-poly(methacrylic acid) copolymer reacted with oxygen; (D) free radical scavenged by oxygen (B-C). Magnetic field sweep, 100 gauss, left to right.

Figure 6. Effect of composition of methanol-water in grafting solution on the extent of graft copolymerization of ethyl acryhte with irradiated celluloses I and II. Magnetic field sweep, 100 gauss, left to right.

100 MeOH IN H 0 . V 0 L . — % 2

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

3,

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53

Extent o f g r a f t i n g was the same f o r both c e l l u l o s e I and I I when the g r a f t i n g s o l u t i o n was methanol (65 vol-%)-water (35 vol-%)· Free r a d i c a l decay was the same f o r both c e l l u l o s e s when methanol (75 vol-%)-water (25 v o l - % ) was used. The i n c r e a s e from 25 v o l - % to 35 v o l - % water from the p o i n t where equal f r e e r a d i c a l decay occurred i n both c e l l u l o s e s (Figure 3) to t h a t where equal extent of g r a f t i n g occurred (Figure 6) may be the r e s u l t o f the added 9 v o l - % e t h y l a c r y l a t e monomer i n the g r a f t i n g s o l u t i o n . E t h y l a c r y l a t e was a poor s w e l l i n g agent f o r c e l l u l o s e (21). The maximum extent o f g r a f t c o p o l y m e r i z a t i o n of e t h y l a c r y l a t e (9 v o l - % ) took p l a c e i n methanol (40 vol-%)-water (60 v o l - % ) f o r both i r r a d i a t e d c e l l u l o s e s ( F i g u r e 6 ) . The boundary c o n d i t i o n f o (9 v o l - % ) a l s o develope g r a f t i n g maximum observed may be due to the i n c r e a s e d amount of monomer a v a i l a b l e f o r r e a c t i o n a t the boundary c o n d i t i o n combined w i t h the accélérâtive e f f e c t o f water. Because water i s a poorer solvent f o r p o l y ( e t h y l a c r y l a t e ) than methanol, i t would tend to cause c o i l i n g and decrease m o b i l i t y o f the growing p o l y ( e t h y l a c r y l a t e ) c h a i n s , thus r e d u c i n g the p r o b a b i l i t y of c h a i n t e r m i n a t i o n (22). P h o t o i n i t i a t i o n . Concentration o f s t a b l e f r e e r a d i c a l s i n cotton c e l l u l o s e i r r a d i a t e d w i t h u l t r a v i o l e t l i g h t i s too low f o r p o s t i r r a d i a t i o n g r a f t i n g r e a c t i o n s to be c a r r i e d out i n the same manner as w i t h c o t t o n exposed to h i g h energy i r r a d i a t i o n . Photoinitiated g r a f t polymerization reactions with cotton c e l l u l o s e r e q u i r e d i r r a d i a t i o n o f the c e l l u l o s e i n the presence of the monomer. Reine e t _ a l . r e p o r t e d the c o p o l y m e r i z a t i o n of a c r y l amide, diacetone acrylamide, methacrylamide and N,N-methyleneb i s a c r y l a m i d e w i t h c o t t o n c e l l u l o s e i n i t i a t e d by near u l t r a v i o l e t l i g h t (23,24). The c e l l u l o s e was padded w i t h aqueous s o l u t i o n s of the monomer and then i r r a d i a t e d w i t h l i g h t from a Rayonet Photochemical Reactor*- , which gave a source o f r a d i a n t energy w i t h about 90% of the l i g h t i n the 3500 A range. Copolymerization took p l a c e o n l y w h i l e c o t t o n c e l l u l o s e impregnated w i t h monomer was i r r a d i a t e d (23). Photoinitiâtion i n a i r , compared w i t h i n i t i a t i o n i n n i t r o g e n , i n h i b i t e d copolymer formation. Apparently oxygen terminated the f r e e r a d i c a l s on the end of the growing polymer c h a i n s , as i n copolymerization of m e t h a c r y l i c a c i d w i t h γ-irradiated c o t t o n c e l l u l o s e ( 6 ) . The ESR s p e c t r a o f c o t t o n c e l l u l o s e samples which were saturated w i t h water and aqueous s o l u t i o n s of acrylamide, d i a c e ­ tone acrylamide, and methacrylamide and then photolyzed f o r 60 min a t 40°C were recorded a t 22°C and a r e shown i n F i g u r e 7. The ESR s p e c t r a o f photolyzed c e l l u l o s e s a t u r a t e d w i t h water (Figure 7A) and w i t h 0.5 M acrylamide (Figure 7B) show l i t t l e

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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evidence of f r e e r a d i c a l formation. On the other hand, the s p e c t r a o f photolyzed c e l l u l o s e s a t u r a t e d w i t h 0.5 M diacetone acrylamide (Figure 7C) and w i t h 0.5 M methacrylamide (Figure 7D) show i n d i c a t i o n s o f f r e e r a d i c a l formation (13). When water or aqueous s o l u t i o n s o f the monomers were photolyzed i n the absence of c e l l u l o s e , there was no d e t e c t a b l e ESR s i g n a l . The ESR s p e c t r a of c o t t o n c e l l u l o s e samples that were saturated w i t h aqueous s o l u t i o n s of the monomers, d r i e d , and then photolyzed f o r 60 min a t 40°C and recorded at 22°C are shown i n F i g u r e 8. Photolyzed, d r i e d c e l l u l o s e generated a s i n g l e t spectrum ( F i g u r e 8A). A s i m i l a r sample, c o n t a i n i n g acrylamide generated a t h r e e - l i n e spectrum (Figure 8B); that c o n t a i n i n g diacetone acrylamide, a doublet spectrum (Figure 8C); and t h a t c o n t a i n i n g methacrylamide 8D). When the pure monomer p o o r l y r e s o l v e d f r e e r a d i c a l s p e c t r a were generated. The h y p e r f i n e s t r u c t u r e o f the ESR s p e c t r a of the propa­ gating r a d i c a l s trapped i n the r i g i d c o t t o n c e l l u l o s e copolymer matrix i n d i c a t e d t h a t t h e r e was r e s t r i c t e d r o t a t i o n about the a "~ R C » » ) . A d d i t i o n o f an i n i t i a t i n g f r e e r a d i c a l to the double bond o f the monomers should y i e l d the propagating r a d i c a l s : C

C

b

o

n

d

8

1 0

2 5

H H

H

R

O II

H

C

B t

L 3

H

O II

R - C - C - CONH , R - C - C - C - N - C - C - C m Δ · I H H CH Η 0

CH , J 0

3

H

ι

CH

Q

J

R - C - C - CONH

0

H The t r i p l e t ESR spectrum o f the acrylamide propagating r a d i c a l i n d i c a t e d t h a t the unpaired e l e c t r o n i n t e r a c t e d w i t h o n l y one o f the methylene hydrogens. I n t e r a c t i o n w i t h both methylene hydrogens would have r e s u l t e d i n a more complex spectrum (9,10). Propagating r a d i c a l s formed i n r i g i d g l a s s e s of a c r y l a t e monomer s o l u t i o n s were found t o e x i s t i n two conformations (9,10). In one, the unpaired e l e c t r o n i n t e r a c t e d w i t h only one of the methylene hydrogens. The doublet ESR spectrum generated by the diacetone a c r y l ­ amide propagating r a d i c a l i n d i c a t e d t h a t the unapried e l e c t r o n i n t e r a c t e d w i t h o n l y one hydrogen. Both methylene hydrogens were out of the plane of i n t e r a c t i o n w i t h the unapried e l e c t r o n (8,10,13).

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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Figure 7. ESR spectra of cotton cellu­ lose I saturated with aqueous monomer solutions and photolyzed for 60 min at 40°C, recorded at 22°C. (A) Water only; (Β) 0.5M acrylamide; (C) 0 . 5 M diacetone acrylamide; (D) 0 . 5 M meth­ acrylamide. Magnetic field sweep, 100 gauss, left to right.

c

Figure 8. ESR spectra of cotton cellu­ lose I photolyzed for 60 min at 40°C and recorded at 22°C. Legends same as Figure 7; cellulose dried prior to pho-

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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The methacrylamide propagating r a d i c a l generated a f i v e l i n e ESR spectrum, a t t r i b u t e d to i n t e r a c t i o n of the unpaired e l e c t r o n w i t h the t h r e e methyl hydrogens and o n l y one of the methylene hydrogens (7^8). R i g i d i t y o f the dry c e l l u l o s e copolymer matrix a t 22°C apparently r e s t r i c t e d the trapped propagating r a d i c a l s t o o n l y one conformation. Propagating r a d i c a l s i n v i n y l monomer p o l y m e r i z a t i o n r e a c t i o n s i n i t i a t e d by l i g h t i n r i g i d g l a s s e s o f monomer-alcohol s o l u t i o n s p h o t o s e n s i t i z e d w i t h f e r r i c c h l o r i d e provided an e x c e l l e n t system f o r i n v e s t i g a t i o n o f the e f f e c t s o f s t r u c t u r a l conformation o f f r e e r a d i c a l s on t h e i r ESR s p e c t r a (8,10), The f i v e - l i n e spectrum generated when a methyl methacrylate (MAA)methanol r i g i d g l a s s c o n t a i n i n g f e r r i c c h l o r i d e was i r r a d i a t e d f o r 2 min a t -170°C show •CH2OH ( F i g u r e 9A). Whe was i n c r e a s e d to -160°C f o r 2 min, then decreased to -170°C, i n t e n s i f i c a t i o n o f the f i v e - l i n e spectrum was recorded ( F i g u r e 9B), On i n c r e a s i n g the temperature t o -150°C f o r 2 min, then decreasing i t t o -170°C, f o u r a d d i t i o n a l l i n e s began to appear i n the spectrum ( F i g u r e 9C). A f t e r f u r t h e r warming to -140°C and then d e c r e a s i n g to 170°C, a n i n e - l i n e spectrum was e v i d e n t (Figure 9D). When the same procedure was a p p l i e d to a r i g i d g l a s s of l a u r y l methacrylate (LMA)-methanol c o n t a i n i n g f e r r i c c h l o r i c e , a f i v e - l i n e s p e c t r a s i m i l a r t o t h a t recorded f o r MMA (Figure 9B) was recorded (7)· Although i r r a d i a t e d g l a s s e s of both LMAmethanol and MMA-methanol were subjected to the same temperature changes, the r a t i o o f i n t e n s i t y o f the f o u r l i n e s to that of the i n i t i a l f i v e l i n e s was much lower i n the LMA spectrum. R i g i d g l a s s e s o f methacrylamide (MA)-methanol c o n t a i n i n g FeClg a l s o have been i r r a d i a t e d w i t h u l t r a v i o l e t l i g h t . The ESR spectrum recorded i n i t i a l l y was s i m i l a r t o t h a t i n F i g u r e 9A. As the temperature o f the i r r a d i a t e d g l a s s was i n c r e a s e d , the spectrum recorded was c l e a r l y a f i v e - l i n e spectrum s i m i l a r to that recorded f o r MMA-methanol (Figure 9B), Continued i n c r e a s e s i n temperature o f the i r r a d i a t e d MA-methanol g l a s s d i d not i n crease the number o f l i n e s o f the ESR spectrum as was the case w i t h MMA and LMA, Propagating r a d i c a l s t h a t would generate a n i n e - l i n e spectrum were not detected when MA was polymerized, Hyperfine s p l i t t i n g o f the propagating r a d i c a l s i n the p o l y m e r i z a t i o n o f methacrylate monomers that generated f i v e - l i n e s p e c t r a were about 0, ± 22, and ± 44 gauss. The h y p e r f i n e s p l i t t i n g s o f propagating r a d i c a l s t h a t generated f o u r - l i n e s p e c t r a were about ± 11 and ± 33 gauss from the center of the s p e c t r a . Free r a d i c a l s generating f o u r - l i n e s p e c t r a were detected o n l y a f t e r formation o f those generating f i v e l i n e s ( F i g u r e 9C). The g-values f o r the c e n t e r s o f the s p e c t r a were about equal t o that f o r f r e e s p i n . Ingram e t a l , (25) proposed

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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Figure 9. ESR spectra of free radicals in ferric nol-methyl methacrylate glass photoirradiated for recorded at -170°C; (B) after warming to -160°C -170°C(C) after further warming to -150°C -170°C; (D) after further warming to -140°C —170°C. Magnetic field sweep, 250

with

57

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chloride-photosensitized 2 min at -170°C. for 2 min, spectra for 2 min, spectra for 2 min, spectra gauss, teft to right.

metha(A) Spectra recorded at recorded at recorded at

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

H . - C - C - O - R t

H

Hem

as the s t r u c t u r e f o r propagating r a d i c a l s detected i n photopolymerizations o f methyl methacrylate i n peroxide o r a z o b i s i s o b u t y r o n i t r i l e p h o t o s e n s i t i z e d methanol-monomer r i g i d g l a s s e s . Two s e t s o f l i n e s , a f i v e - l i n e s e t and a weaker f o u r - l i n e s e t , composed the n i n e - l i n e spectrum. The f i v e - l i n e s e t was a t t r i buted t o i n t e r a c t i o n o f the unpaired e l e c t r o n w i t h one o f the methylene hydrogens and the t h r e e hydrogens o f the methyl group. The remaining f o u r l i n e s were e x p l a i n e d on the b a s i s that some o f the f r e e r a d i c a l s had s t r u c t u r a of the methylene hydrogen e l e c t r o n and o n l y the methyl group i n t e r a c t e d w i t h the unpaired e l e c t r o n t o generate a f o u r - l i n e spectrum. Recording o f a f i v e - l i n e ESR spectrum w i t h the i r r a d i a t e d glasses i n t h e absence o f a f o u r - l i n e spectrum ( F i g u r e 9B) i n d i c a t e s t h a t a t lower temperatures the propagating r a d i c a l s i n the r i g i d g l a s s e s were i n a s t r u c t u r a l conformation t h a t allowed o n l y one o f the methylene hydrogens and methyl group t o i n t e r a c t w i t h the unpaired e l e c t r o n . As the temperatures o f the r i g i d g l a s s e s were i n c r e a s e d , r o t a t i o n about the C - Cg bond took p l a c e so t h a t i n some o f the propagating r a d i c a l s n e i t h e r o f the methylene hydrogens i n t e r a c t e d w i t h the unpaired e l e c t r o n ; e v i d e n t l y a f r e e l y r o t a t i n g methyl group i n t e r a c t e d w i t h the unpaired e l e c t r o n t o generate a f o u r - l i n e spectrum. a

S t e r i c hindrance due t o c h a i n entanglement, bulky e s t e r groups, o r hydrogen bonding as proposed f o r methacrylamide (7.,8) would tend to f a v o r one s t r u c t u r a l conformation o f the propagating r a d i c a l over o t h e r s . The s t r u c t u r a l conformation assumed by the monomers as the temperature was lowered to form the r i g i d g l a s s e s probably determined i n i t i a l conformation o f the propagating r a d i c a l s . Hydroxyl R a d i c a l I n i t i a t i o n . G r a f t c o p o l y m e r i z a t i o n r e a c t i o n s o f v i n y l monomers w i t h c o t t o n c e l l u l o s e have been i n i t i a t e d by generating hydroxyl r a d i c a l s i n the presence o f c o t t o n c e l l u l o s e and monomer, u s i n g the Fe I^"p2 (26,27). Although t h e proposed mechanism o f r e a c t i o n i n v o l v e d a hydroxyl r a d i c a l a b s t r a c t i o n o f a hydrogen atom from the c e l l u l o s e , no evidence was obtained f o r the h y d r o x y l r a d i c a l or the r a d i c a l generated on the c e l l u l o s e . s

v

s

t

e

m

E l e c t r o n s p i n resonance i n v e s t i g a t i o n s of the ^reactions between ^ e h y d r o x y l r a d i c a l s generated by the Fe /&2®2 using T i i n s o l u t i o n as ajji i n d i c a t i n g i o n , the ESR spectrum of the h y d r o x y l r a d i c a l - T i complex was recorded (28). s

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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s

t

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Figure 10. ESR spectra of free radicals trapped in the cellulose I-Fe / +2

gauss, left to right.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

Cotton cellulose immersed in 0.1 M FeSO , dried in a flowing stream of nitrogen, was placed in a quartz tube, and 0.3 M H O saturated with acrylonitrile monomer was drawn onto the cellulose. Immediately, liquid nitrogen was drawn through the tube, freezing the wet cellulose. The ESR spectrum of the free radicals trapped in the frozen matrix was recorded at -110°C (Figure 10). The spectrum generated in the presence of the acrylonitrile monomer was more intense than that generated in the cellulose in the absence of the monomer (5). Free radicals generated during the graft copolymerization reaction were more stable than cellulosic free radicals. The effect of temperature on the formation of free radicals initiated in the cellulose/Fe -H2O2/acrylonitrile system is shown in Figure 11. Dry cellulos containin ferrou io t with 0.03 M H2O2, saturated frozen in liquid nitrogen. At -70°C or below the free radical concentration remained constant. When the temperature was increased above -70°C, free radical concentration increased with time. Above -40°C, free radical concentration approached a maximum value. ESR results indicate that cellulosic free radicals generated by the hydroxyl radicals are easily terminated at temperatures above -60°C. In the absence of monomer, the cellulosic free radicals are probably terminated by reaction with hydroxyl radi­ cals. However, in the presence of monomer, the hydroxyl radicals attack both the cellulose and the monomer, thus generating two types of free radicals. The cellulosic free radicals can ini­ tiate chain polymerization reactions, as well as terminate reactions which would otherwise result in homopolymer formation. In either case, a cellulose - poly (acrylonitrile) graft is produced. 4

2

2

Abstract Graft polymerization reactions of vinyl monomers with cot­ ton cellulose were initiated by free radicals produced in cotton by cobalt-60γ-radiation, ultraviolet (uv) radiation, and oxidation-reduction reactions. Electron spin resonance (ESR) spectroscopy was used to investigate reactions of initiating radicals and propagating radicals in graft polymerization reac­ tions. Effects of solvents on stability of free radicals in γ-irradiated cotton cellulose were correlated with their effects on extent of grafting of ethyl acrylate onto irradiated cotton. The ESR spectra of methacrylic acid (MAA) propagating radicals trapped in the copolymer matrix at room temperature when the graft polymerization of MAA onto γ-irradiated cotton was stopped were similar to the ESR spectra of free radicals trapped in

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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Copolymerization of Vinyl Monomers with Cotton 61

γ-irradiated methyl methacrylate polymer. Propagating radicals in the uv-radiation initiated graft polymerization of acrylamide, methacrylamide, and diacetone acrylamide generated different ESR spectra for each system. Changes in the ESR spectra of free radicals generated in ferric chloride-photosensitized polymeri­ zation reactions reflected changes in conformational structure of the propagating radicals. ESR spectra of initiating and propagating radicals in the polymerization of acrylonitrile onto cotton initiated by the ferrous ion-hydrogen peroxide system were recorded. Literature Cited 1. J. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18.

Arthur, J. C., Jr., 36, 630-635 (1966) Arthur, J. C., Jr., Hinojosa, O., and Tripp, V. W., J. Appl. Polym. S c i . 13, 1497-1507 (1969). Hinojosa, O., Nakamura, Υ . , and Arthur, J. C., Jr., J. Polym. S c i . Part C 37, 27-46 (1972). Reine, Α. Η . , Hinojosa, O., and Arthur, J. C., Jr., J. Polym. S c i . Part Β 9, 503-507 (1971). Arthur, J. C., Jr., Hinojosa, O., and Bains, M. S., J. Appl. Polym. S c i . 12, 1411-1421 (1968). Hinojosa, O. and Arthur, J. C., Jr., J. Polym. S c i . Part Β 10, 161-165 (1972). H a r r i s , J. Α., Hinojosa, O., and Arthur, J. C., Jr., Polym. Prepr. Amer. Chem. Soc. Div. Polym. Chem. 13, 479-484 (1972). H a r r i s , J. Α., Hinojosa, O., and Arthur, J. C., Jr., J. Polym. S c i . Polym. Chem. Ed. 11, 3215-3226 (1973). H a r r i s , J. A. Hinojosa, O., and Arthur, J. C., Jr., Polym. Prepr. Amer. Chem. Soc. Div. Polym. Chem. 15, 491-494 (1974). H a r r i s , J. Α . , Hinojosa, O., and Arthur, J. C., Jr., J. Polym. S c i . Polym. Chem. Ed. 12, 679-688 (1974). Dilli, S., Ernst, I . T . , and Garnett, J. L., Aust. J. Chem. 20, 911-927 (1967). Nakamura, Y., Hinojosa, O., and Arthur, J. C., Jr., J. Polym. S c i . Part C 37, 47-55 (1972). Reine, Α. H., Hinojosa, O., and Arthur, J. C., Jr., J. Appl. Polym. S c i . 17, 3337-3343 (1973). Ogiwara, Y., Hon, Ν., and Kubota, H., J. Appl. Polym. S c i . 18, 2057-2068 (1974). Hinojosa, O., Harris, J. Α., and Arthur, J. C., Jr., Carbohyd. Res. 41, 31-39 (1975). Baxendale, J. Η., Evans, M. G., and Park, G. S., Trans. Faraday Soc. 42, 155-169 (1946). Haber, F . and.Weiss, J., Naturwissenschaften 20, 948-950 (1932). Haber, F . and Weiss, J. Proc. Roy. Soc. (London) A 147, 332-351 (1934).

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

62 19. 20. 21. 22. 23. 24. 25. 26. 27. 28.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY Byrne, G. A. and Arthur, J. C., Jr., J. Appl. Polym. S c i . 14, 3093-3103 (1970). Abraham, R. J., M e l v i l l e , H. W., Ovenall, D. W., and Whiffen, D. Η . , Trans. Faraday Soc. 54., 1133-1139 (1958). Nakamura, Υ., Hinojosa, O., and Arthur, J. C., Jr., J. Appl. Polym. S c i . 13, 2633-2641 (1969). Trommsdorff, Ε., Kohle, Η., and Lagally, P . , Makromol. Chem. 1, 169-198 (1948). Reine, A. H. and Arthur, J. C., Jr., Text. Res. J. 42, 155158 (1972). Reine, Α. Η . , Portnoy, Ν. Α., and Arthur, J. C., Jr., Text. Res. J. 43, 638-641 (1973). Ingram. D. J. E., Symons, M. C. R . , and Townsend, M. G . , Trans. Faraday Soc Richards, G. N., J. Bridgeford, D. J., Ind. Eng. Chem., Prod. Res. Dev. 1, 45-52 (1962). Bains, M. S., Arthur, J. C., Jr., and Hinojosa, O., J. Phys. Chem. 72, 2250-2251 (1968).

*Mention of companies or commercial products does not imply recommendation by the U. S. Department of Agriculture over others not mentioned.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

4 Liquid Ammonia Treatment of Cotton Fabrics S. ALLAN HEAP International Institute for Cotton, Manchester, England

The last few year hav th development d commercial introduction of a bran anhydrous liquefied ammonia as a setting agent for cotton fabrics. IIC has been sponsoring background research on several aspects of this process, mainly at the University of Stuttgart and the Norwegian Textile Institute, and I would like to discuss two topics from this programme today:1. The influence of the ammonia content of the fabric upon its deformability, 2. Easy-care finishing of ammonia treated fabrics; a comparison of the low-add-on crosslinking technique with the normal padding method. But first, bywayof introduction, a few data which have already been published in the German language but may not have been seen here, and which draw some comparisons between NH3 and caustic soda treatments. Figure 1 illustrates the swelling (change in thickness) of an unrestrained poplin fabric as a function of time and the concentration of ammonia. Two points are immediately obvious; the very rapid rate of the reaction and the sensitivity to the presence of moisture, When we expand the time scale by speeding up the chart, it is clear that for anhydrous ammonia, essentially all the swelling takes place within the first fifteen seconds. Figure 2 shows a comparison between anhydrous ammonia and caustic soda in the yarn untwisting test. Ammonia shows a clearly faster rate of swelling, but a lower equilibrium value. Although the equilibrium swelling of the fibres is less in NH3 than in NaOH, fabric shrinkage tends to be about the same when little or no restraint is applied. The actual difference depends upon the fabric construction and presumably can be explained by assuming that fibres are prevented from reaching their maximum degree of swelling, especially in caustic soda. Indeed, the caustic swollen fabric is much more easily prevented from shrinking by the application of a restraining force (Figure 3). 63

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

Ù

Nf

NH /Ç%H 0 3

2

NH /lS%HzO z

S 10 min TIME Of SWELLING Figure

1.

Swelling of bleached liquid ammonia/water

cotton poplin (~ —40°C)

fabric

in

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

4.

HEAP

Liquid

Ammonia

Treatment

of Cotton

Fabrics

65

When the f a b r i c i s held to constant dimensions, the f o r c e generated by ammonia s w e l l i n g i s g e n e r a l l y much l a r g e r than that caused by c a u s t i c soda (Figure 4 ) . Furthermore, the a p p l i c a t i o n of a pretension to the f a b r i c , before contact with the s w e l l i n g agent produces a marked reduction i n the s w e l l i n g f o r c e generated by NaOH, but has apparently almost no i n f l u e n c e on the NH3 system (Figure 5 ) . The l a r g e i n f l u e n c e of tension upon the degree o f s w e l l i n g of cotton f i b r e s i n c a u s t i c soda i s , of course, w e l l documented, so the apparent i n s e n s i t i v i t y of the ammonia system to tension was rather s u r p r i s i n g . I t has l e d us p r o v i s i o n a l l y to conclude that the ammonia c e l l u l o s e complex i s rather d i f f e r e n t from a l k a l i c e l l u l o s e , e s p e c i a l l y i n i t s mechanical p r o p e r t i e s , with l i t t le c a p a b i l i t y f o r stres t h i s behaviour i s that the dimensions of a f a b r i c i n the ammonia process than i n mercerising. Figures 6 and 7 , which p i c t u r e the length changes during t y p i c a l s w e l l i n g c y c l e s w i l l serve to i l l u s t r a t e the point a l i t t l e further. Figure 6 i s supposed to model a s l a c k s w e l l i n g and r e s t r e t c h ing c y c l e . Note the s i m i l a r degree of shrinkage with a f a s t e r r a t e f o r N H 3 . The f a b r i c was then loaded with lKg per cm. bef o r e removal of the s w e l l i n g agent. The c a u s t i c - s w o l l e n sample immediately s t r e t c h e d s i g n i f i c a n t l y , with a f u r t h e r r e s t r e t c h i n g as soon as the water r i n s i n g bath was a p p l i e d . The ammonia swollen sample, however, extended f a r l e s s on f i r s t applying the l o a d , and there was a c l e a r delay a f t e r the s t a r t of evaporation before r e s t r e t c h i n g began. In Figure 7 , the c y c l e i l l u s t r a t e d i s one where a pretension i s a p p l i e d before s w e l l i n g . This tension was s u f f i c i e n t to more or l e s s eliminate shrinkage i n NaOH, but there was s t i l l a f a i r degree of shrinkage i n N H 3 . Once again, during evaporation of NH3 there was a delay period during which no extension occurred. Concentration

Of NH3 On The F a b r i c .

The thought n a t u r a l l y a r i s e s that t h i s block to the extens i b i l i t y of ammonia swollen f a b r i c should be r e l a t e d to the conc e n t r a t i o n of ammonia remaining i n the f i b r e s . Figure 8 shows the values obtained from the instantaneous elongation experienced by s l a c k swollen samples, as a f u n c t i o n of the load a p p l i e d and the ammonia content at the i n s t a n t of a p p l i c a t i o n of the l o a d . Three l e v e l s of ammonia are shown to i l l u s t r a t e the extremes and an intermediate i n the family of curves. C l e a r l y , the highl y swollen m a t e r i a l i s very r e s i s t a n t to elongation, and t h i s must be a b a s i c f i b r e property s i n c e the f a b r i c s t r u c t u r e w i l l be jammed at f u l l s w e l l i n g . Only when the f i b r e s w e l l i n g i s reduced s u f f i c i e n t l y to create space i n the f a b r i c w i l l elongat-

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

Figure

3. Shrinkage of bleached cotton poplin fabric, (left) in liquid monia (~ —40° C); (right) in 20% aqueous NaOH (20°C)

TIME Of TREATMENT Figure 4.

Development

of tension during

swelling

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

am-

4.

Liquid

HEAP

Figure

6.

Ammonia

Treatment

Shrinkage and elongation

of Cotton

67

Fabrics

of cotton poplin fabric during NH and treatments 3

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

NaOH

68

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

(warp)

TENSION

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

4.

HEAP

Liquid

Ammonia

Treatment

of Cotton

69

Fabrics

ion become p o s s i b l e at reasonable l o a d s . There i s also the p o s s i b i l i t y that at some intermediate ammonia content the f i b r e i t s e l f becomes capable of easy elongation as the ammonia c e l l ulose complex i s broken down. Both mechanisms ( f a b r i c jamming and f i b r e e x t e n s i b i l i t y ) w i l l presumably be a f f e c t e d by the manner of ammonia removal - i n p a r t i c u l a r , one might expect d i f f e r e n c e s between the cases where ammonia i s removed by "dry" evaporation on the one hand, or by replacement with water on the other. Up to now, we have studied only the evaporation systems i n t h i s respect. Figure 9 shows a t y p i c a l r e s u l t when one a p p l i e s a constant load during evaporation of the ammonia. R e s t r e t c h i n g begins at an ammonia concentration of about 55%, and one can suppose t h i s f i g u r e to i n d i c a t e approximatel i n n i n g to remove ammoni evaporating i n t e r s t i t i a l l i q u i d . We have other c i r c u m s t a n t i a l evidence p o i n t i n g to a f i g u r e i n the region of SQ% f o r the within fibre liquid. This 50% NH3 f i g u r e does not correspond to the c r i t i c a l point as c o n v e n t i o n a l l y defined during drying processes, when the r a t e of drying and the f a b r i c temperature changes abruptly due to the greater d i f f i c u l t y of removing more t i g h t l y bound liquid. Figure 10 shows t h a t , f o r one set of circumstances, we found t h i s c r i t i c a l point to be i n the region of 35% N H 3 . This l a t t e r value happens to agree p r e t t y w e l l with a c a l c u l a t e d three moles of NH3 per glucose r e s i d u e . Recently, we have been c o n s i d e r i n g the p o s s i b i l i t y that a 50-60JÎ l e v e l of add-on may be a l l that i s t e c h n i c a l l y needed to produce the d e s i r a b l e e f f e c t s of ammonia treatment and we have made a f a i r l y l a r g e number of s t u d i e s i n t h i s area. So f a r , the r e s u l t s are i n c o n c l u s i v e and not p a r t i c u l a r l y encouraging. Easy-Care-Finishing. A range of samples was prepared on continuous p i l o t s c a l e equipment by applying i n c r e a s i n g l e v e l s of DHDI lEU/l lgCl2 to ammonia t r e a t e d , mercerised, and c o n t r o l f a b r i c s . On the one hand, the usual padding technique was used to apply the c r o s s l i n k i n g l i q u o r , and on the other hand, the new Low-Add-On (LAO) system was used. In the LAO system, the amount of l i q u o r appl i e d can be c o n t r o l l e d at such a l e v e l ( 3 D - 3 5 ^ ) that e s s e n t i a l l y no migration ensues during drying and a more uniform d i s t r i bution of c r o s s l i n k i n g i s obtained i n the f i n a l f a b r i c . A wide range of q u a l i t i e s were processed which a l l gave s i m i l a r r e s u l t s , t h e r e f o r e , j u s t one set of r e s u l t s i s presented here today. The mercerised samples gave r e s u l t s very s i m i l a r to those of the c o n t r o l s and t h e r e f o r e , these are not i n c l u d e d . Generally speaking, the use of the LAO system gave b e t t e r crease recovery angles and/or b e t t e r abrasion r e s i s t a n c e f o r v

v

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE

my

I

ι_ 160

I ίΟΟ

ι

A N D PAPER

CHEMISTRY

I ι I ι I ι I ZO 60 40 20 AMMONIA ON FABRIC

1

A N D TECHNOLOGY

1—

0%

Figure 9. Degree of restretching of cotton poplin as a function of ammonia concentration on the fabric

\

\ \

\

\

\

d\p

era

J _ l

10

'

1

20

'

'

•

'

1

30 40 NH CONTENT

1

SO

60%

3

Figure 10.

Fabric temperature

during

drying

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

4.

71

Liquid Ammonia Treatment of Cotton Fabrics

HEAP

g<4 30V

§

2θ\

Δ HO RESIN Ο PAO

^ ^

FILLED SYMBOLS

•^

10 -

ΝΗ 7*ΕΆΤ€0 3

-L 200 220 240 260 230 DRY WRINKLE RECOVERY

300

Δ no nest*

MEAN TEAR STRENGTH #00 A

O

PAD

•

LAO

FILLEO SYMBOLS NH TREATED

#

3

& 1400

V

Ο

200 600

^

•

•

I

Ο

30\^

I

Ο

S

A S0

Figure

12. Mean tear

strength

Ο

PAD

·

• CAO is -

L

Ο

Δ NO RESIN

L

^ δ

I

200 220 240 260 280 300 DRY WRINKLE RECOVERY 4MCE, decree?

· O

FILLED SYMBOLS 3 SEATED

D

·

NH

•

•

•

• •

200 220 240 260 230 300 DRV WRINKLE RECOVERY ANGLE, decrees

Figure

13. Accelerotor loss

6 min weight

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

the same s o l i d s add-on of c r o s s l i n k i n g agents but t e n s i l e and tear s t r e n g t h were about the same as the c o n t r o l s . The ammonia t r e a t e d samples showed c o n s i s t e n l y b e t t e r crease recovery, t e n s i l e s t r e n g t h , tear strength and abrasion r e s i s t a n c e f o r a given s o l i d s add-on. The combination of an ammonia pretreatment and the LAG system gave the best r e s u l t s of a l l . Figures 11, 12 and 13 summarise the t e n s i l e , tear and A c c e l e r o t o r weight l o s s f i g u r e s f o r a sheeting f a b r i c of the European type (about 15Gg/m ), as a f u n c t i o n of the dry crease recovery angles - the so c a l l e d balance of p r o p e r t i e s which every cotton f i n i s h e r has to optimise. The most s t a r t l i n g r e s u l t s are those f o r tear strength and abr a s i o n r e s i s t a n c e where the combination of ammonia pretreatment and MA f i n i s h allowed creas with mechanical s t r e n g t trol. This improvement can be a t t r i b u t e d f i r s t l y to the very e f f e c t i v e s e t t i n g e f f e c t of the ammonia treatment (which cons i d e r a b l y reduces the i n t e r - y a r n f r i c t i o n , thus improving tear strength and crease r e c o v e r y ) , and secondly to the high e f f i c i ency of u t i l i s a t i o n of the c r o s s l i n k i n g agent due to the improved u n i f o r m i t y of d i s t r i b u t i o n of the c r o s s l i n k e r brought about by the use of the LAO f i n i s h i n g system. 2

Acknowledgement. G r a t e f u l thanks are due to Dr. K a r l Bredereck, Mr. Harald Jensen, and Mr. Bob Leah f o r ideas and experimental work i n S t u t t g a r t , Bergen and Manchester r e s p e c t i v e l y .

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

5 Synthesis and Testing of Biodegradable Fiber-Forming Polymers S. J. HUANG, J. P. BELL, J. R. KNOX, H. ATWOOD, K. W. LEONG, K. NATARAJAN, J. PAVLISKO, M. ROBY, and N. SHOEMAKER Departments of Chemistry and Chemical Engineering, Biological Science Group, and Institute of Materials Science, University of Connecticut, Storrs, CT 06268

Recent literature biodegradability syn thetic polymers is mostly concerned with the problem of prevent­ ing or retarding attack on synthetic polymers and plastics by micro-organisms (1-9). Potts and coworkers reported in 1973 an extensive study on the biodegradability of synthetic polymers by micro-organisms (10). They reported that aliphatic polyesters and polyester based polyurethanes were the only classes of syn­ thetic high molecular weight polymers found to be biodegradable in a study embracing a large number of synthetic polymers such as polyesters, polyamides, polyoleffins, and polyurethanes. Unfor­ tunately the degradable aliphatic polyesters generally lack the desirable physical properties necessary for many applications. The microbial degradation of cellophane and amylose films has been studied by Carr and coworkers (11, 12). It has been reported by several workers that low molecular weight normal paraffins and low molecular weight polyethylene supported some microbial growth (10, 13-15). Efforts have been directed toward the synthesis of photodegradable polymers so that segments from photodegradation of the polymers might become bio­ degradable (16-18). Attempts have also been made to improve the biodegradability of polymer composites by mixing biodegradable biopolymers such as starch with nondegradable synthetic polymers such as polyethylene (19). Currently there are very few reported studies on truly bio­ degradable synthetic polymers that have the desirable physical properties necessary for the production of a wide range of biode­ gradable plastics, films, and fibers. Bailey and coworkers have reported that some copolymers ofα-aminoacidsand longer amino­ -acids were metabolized by soil micro-organism (20). It has been reported by Gilbert and coworkers that Borax, a polyacrylonitrile based resin, was utilized by micro-organism (21). Polyenamine was found to be degradable (22). Biodegradable polyurethane has

73

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

been obtained from the modification of cellulose (2β). Polyglycolate i s being used as surgical suture. It became apparent from the above mentioned l i t e r a t u r e that useful biodegradable polymers w i l l have to come from new synthe­ t i c approaches designed to incorporate biodegradable structural units into polymer chains having desirable physical properties. Biodegradable fiber forming polymers should find uses i n surgical inplants, sutures, controlled release drags, f e r t i l i z e r s , fungi­ cides, nematocides, mulch, etc.. Our efforts i n biodegradable polymers have been directed toward two areas. F i r s t l y , we are modifying biodegradable poly­ mers to improve their physical properties so that useful biode­ gradable plastics, films we are designing, synthesizing might be biodegradable and have the desirable physical propers ties. Biodégradation Methods Most of the above mentioned biodégradation studies involve s o i l b u r i a l tests or culturing on agar-immersed samples. While our degradation testing includes these methods, we have developed procedures for exposing polymer materials to concentrated enzyme solutions i n order to accelerate the degradation reaction and to be able to establish the chemistry and kinetics of a single reaction i n the absence of side reactions originating i n the microorganism. Details of our biodégradation methods have been reported recently (24)· Results Cross-linked Gelatin. Gelatin, an animal by-product, i s available i n quantity and i s relatively low priced. It i s water soluble and consists of protein chains of Mn 30,000 - 50,000. Among the aminoacid components of gelatin are lysine and a r g i nine. The amino side groups of lysine and arginine residues provide suitable sites for modifications of gelatin. Our goal has been to produce a material which i s water insoluble yet pliable enough to be used as fibers, ribbons, or sheets. The material would at the same time be easily biodegradable since the main component i s protein. Water insoluble materials have been obtained by cross-linking of gelatin with various reagents (2$). We studied the cross-linking reactions of gelatin with diacid chlorides, dialdehydes, and diisocyanates and found that d i i s o cyanates are most suitable for our purpose. We have succeeded i n cross-linking gelatin using different conditions: i n t e r f a c i a l cross-linking, bulk cross-linking, and cross-linking of drawn fibers.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

5.

HUANG ET AL.

75

Biodegradable Fiber-Forming Polymers

Draw f i b e r s o f g e l a t i n were prepared by b l e n d i n g a p l a s t i c i z e r and water with g e l a t i n p r i o r t o e x t r u s i o n a t 60 C s i n c e melt e x t r u s i o n i s not s u i t a b l e due t o the thermal i n s t a b i l i t y o f g e l a ­ tin. The t e n s i l e p r o p e r t i e s o f the f i b e r s v a r y with the nature o f the p l a s t i c i z e r . G l y c e r i n e produced a r e l a t i v e l y weak but e l a s t i c f i b e r , whereas g l y c o l i n c r e a s e d the modulus but gave v e r y b r i t t l e t e n s i l e behavior. Diethylene g l y c o l i n c o r p o r a t e d the hugh modulus o f the ethylene g l y c o l with the h i g h e l o n g a t i o n o f the g l y c e r i n e i n t o much more acceptable t e n s i l e p r o p e r t i e s . The fibbers were c r o s s - l i n k e d by treatment with jfo s o l u t i o n o f 1,6-diisocyantohexane i n toluene a t 60 C f o r l / 2 n r . The c r o s s l i n k e d f i b e r s are i n s o l u b l e i n water and have much improved t e n ­ s i l e p r o p e r t i e s , Table Table 1.

Tensile Properties of Gelatin F i b e r s

3 ,

Tensile, p s i Plasticizer

Before C r o s s - l i n k .

After Cross-link.^

Glycerine

1,000

3 200

Ethylene g l y c o l

1,800

2,100

Diethylene g l y c o l

7 000

13 600

Triethylene glycol

3,300

4,500

f

f

f

Polyethylene g l y c o l

Mn - 200

6,600

10,000

a.

G e l a t i n : p l a s t i c i z e r : water = 2 % 1

:

1.

b.

C r o s s - l i n k e d with jfo 1,6-diisocyanatohexaiie i n toluene a t 60 C f o r 1/2 n r .

Removal o f the p l a s t i c i z e r and water p r i o r t o the c r o s s l i n k i n g by washing the f i b e r s with e t h a n o l f u r t h e r improved the p r o p e r t i e s o f the f i b e r s . F i b e r s prepared with d i e t h y l e n e g l y ­ c o l , elongated 75$f and washed with ethanol f o l l o w e d by c r o s s l i n k i n g have a t e n s i l e s t r e n g t h o f 29,5βΟ p s i . A l l the c r o s s - l i n k e d g e l a t i n f i b e r s were found t o be degra­ dable by p r o t e o l y t i c enzymes such as papain, s u b t i l 1 s i n , and t r y p s i n . Up t o 90$ degradation as compared with the degradation o f untreated g e l a t i n was observed. E l o n g a t i o n o f the f i b e r s be­ f o r e and a f t e r c r o s s - l i n k i n g showed no e f f e c t on the biodegrada­ bility.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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New Polymers. 1.Polyamides. Our i n i t i a l testing showed that nylon—6 and nylon-6,6 r e s i s t enzyme hydrolysis. Since proteolytic enzymes are specific i n cleaving peptide linkages adjacent to either hy­ drophobic or hydrophilie substituents we decided to synthesize polyamides with substituents, anticipating that the introduction of the suitable substituent would make the polyamide more sus­ ceptible to enzyme cleavage. Benzylated polyamides, nylons-n,6Bz (η a 2,4|6,β), were pre­ pared by the i n t e r f a c i a l polymerization of ct-benzyladipoyl chlo­ ride with al4orleneoi.ajiiines. A l l but the nylon-2,6Bz are fiber forming. Unfortunately found to be extremely low nylon-6,6Bz) was found to be hydrolyzed by papain. —^NH(CH ) NHC0CH CH CH CHC0-^-2

n

2

2

2

CH Ph 2

Nyloiwi 6Bz f

sp. 145°C

η = 2

Mn 13,400

η =4

140

29,100

η .6

120

19,900

η =8

105

8,500

Nylon-6,3Bz, prepared from hexamethylenediamine and benzylmalonic acid, was found to be degradable by chymotrypsin — 20$ hydrolysis after 10 day exposure. However, we have not been able to prepare polymers of high enough molecular weight that i s fiber forming.

-Hffl(CH ) NHC0ÇHC0-92

6

^

l

o

ï

^

t

3

B

Z

CH Ph 2

ntp 140-145°C Mn 2,000

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

5.

HUANG ET AL.

Biodegradable

Fiber-Forming

Polymers

77

Fiber forming poly (2-hydroxy-l, 3-propylene sebacamide) and poly(l,2-propylene sebacamide) were found to be degraded readily by the fungi Aspergillus niger and Aspergillus flavus. A fiber forming Ij/l copolymer prepared from 2-hydroxy-l, 3-propyleneoiamine and 1,2-propylenediamine and sebacyl chloride was degraded by both protease Κ and s u b t i l i s i n . The copolymer has a mp 200 - 210 and Mn 13,000·

-E- NHCHCHCHNHC0 (CH^CO 4 2

2

0H poly (2-hydroxy-l dec. 225°C

Mn

20,000

-E- NHCHCHNHC0 (CH ) C0 -J2

2

e

CH

3

poly(l,2-propylene mp 223-22B°G

sebacamide) Mn 8,300

2· PoLyu^ea. Lysine methyl and ethyl esters were converted into polyureas by the reaction with 1,6-diisocyanatohexane. The polyureas are degradable by chymotrypsin and s u b t i l i s i n and sup­ ported the growth of Aspergillus niger.

-ENH(CH)^CHNHCOÎÎH(CH)NHCO-42

2 6

COOR R == methyl and ethyl polyureas R = methyl

mp 106-108°C

Mn 5,900

R = ethyl

mp 125-129°C

Mn 17,900

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

The i n t r o d u c t i o n o f proper s u b s t i t u e n t does improve the b i o ­ d e g r a d a b i l i t y o f polyamides and p o l y u r e a s . However, the racemic s u b s t i t u t e d polymers tend t o have low c r y s t a l l i n i t y and s o f t e n ­ i n g peints. The use o f o p t i c a l l y pure monomers should g i v e s t e r o r e g u l a r polymers o f h i g h c r y s t a l l i n i t y and h i g h s o f t e n i n g p o i n t s . The b i o d e g r a d a b i l i t y o f the r i g h t o p t i c a l l y a c t i v e monomer w i l l a l s o g i v e polymer o f much h i g h e r b i o d e g r a d a b i l i t y than the r a c e ­ mic polymers. However, with the exception o f a*-ajiiinoacids o p t i ­ c a l l y pure monomers are g e n e r a l l y not a v a i l a b l e . Since our r e ­ s u l t s mentioned so f a r and t h a t o f B a i l e y i n d i c a t e d t h a t c o p o l y ­ mers are g e n e r a l l y more degradable than the corresponding homopolymers we decided t o prepared copolymers with v a r i o u s l i n k a g e s instead of various substituen 3· Poly(amide-este3>-urethane) . P o l y c a p r o l a c t o n e was r e ­ p o r t e d t o supported f u n g i growth (10 )· However, i t s poor physc a l p r o p e r t i e s (mp 60 C and low t e n s i l e ) l i m i t the use o f t h i s polymer. We have converted p o l y c a p r o l a c t o n e i n t o a new p o l y (amide-esteru-urethane) by r e a c t i n g i t with ethanolamine and r e p o l y m e r i z e i n g the r e s u l t i n g p o l y e s t e 3 > - a m i d e d i o l with 1 , 6 - d i isocyanatohexane. The r e s u l t e d copolymer has a n i t r o g e n content o f 1.0$, i n d i c a t i n g one o f each 19 caprolactone u n i t s was r e a c t e d t o the ethanolamine. Only a v e r y s l i g h t m e l t i n g peak was ob­ served a t 320-330 Κ by DSC, due t o r e s i d u e c r y s t a l l i n e segments o f polyester© The polymer was extruded i n t o a monofilament a t 95°C. The u l t i m a t e percentage e l o n g a t i o n o f the drawn f i b e r was 350$ , and the undrawn, 1,000$. The t e n s i l e s t r e n g t h o f the drawn f i b e r was around 17,000 p s i . The o r i g i n a l p o l y c a p r o l a c t o n e has t e n s i l e s t r e n g t h w e l l below 2,000 p s i .

p o l y (amide-ester^urethane )

The copolymer was found t o support the growth o f A s p e r g i l l u s f l a v u s and Pénicillium funiculosum. Ten-day exposure t o urease r e s u l t e d i n 25% degradation. Renin, an enzyme produced by the A s p e r g i l l u s s t r a i n s , a l s o degraded the copolymer but i t was not as e f f e c t i v e as urease.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

5.

HUANG ET AL.

Biodegradable Fiber-Forming Polymers

79

4 · Poly(amide-urethane ). A poly(amde-urethane) was pre­ pared from ethanolamine, sebacyl chloride, and 1,6-diisocyanatohexane. The crystalline and fiber forming copolymer was found to be degradable by protease-K. It represent a very promising class of polymer since i t combines the desirable physical pro­ perties with biodegradability. - Ε " 0CH CH NHC0 (CH ) C0NHCH CH 00CNH(CH ) NHC0 4 2

2

2 e

2

2

2 6

Poly (amide-urethane )

Summary Modification of gelatin drawn fibers by cross-linking gave fibers of much improved properties. Substituted polyamides and polyureas were prepared and some of them are suitable for b i o ­ degradable fibers. Copolymers of various linkages are very pro­ mising biodegradable polymers. Acknowledgement The financial supports from U.S. Army Natick Laboratories, National Science Foundation, and The University of Connecticut Research Foundation are gratefully acknowledge. Literature Cited 1. 59,

Kaemf, G . , Papenroth, w. and Holm, R . , Farbe Lack (1973), 9. 2. Monk, D. W. Text. Res. J. , (1972), 42, 741. 3. Osman, J. L. Klausmeier, R. E . and Jamison, Ε . I . Mater. Proc. Int. Biodeterior. Symp., (1971), 2, 66. 4. Fields, R. D. and Rodriguez, F.,"Proc. 3rd Int. Biodegrada­ tion Symp.", Sharpley and Kaplan, Eds., 775, Applied Science Publishers, London, 1976. 5. Tirpack, G. SPE J., (1970), 26, 26. 6. Darby, R. T. and Kaplan, A . M . , Appl. Microbiol., (1968), 16, 900. 7. Wassell, C. J., SPE Trans., (1964), 193. 8. Jen-Hao, L . and Schwartzm A., Kunstoffe, (1960), 51, 3 1 7 · 9. Huek, H. J., Plastics, (1960), 419. 10. Potts, J. E. Clendining, R. Α., Ackart, W. B. and Niegisch, W. D., "Polymers and Ecological Problems", G u i l l e t , E d . , 6 l , Plenum Press, N. Y., 1973.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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11. 12. 13. 14. 15. 16. 17. 18. 19. 20.

21.

22. 23. 24.

25.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

Engler, P. and Carr, S. H. J. Polym. S c i . Polym. Phys. E d . , (1973), 11, 313. Bradley, S. A. Engler, P. and Carr, S. H. Appl. Polym. Symp., (1973), 22, 269. Merdinger, E . and Merdinger, R. P. Appl. Microbiol., (1970), 20, 561. Barna, P. K. et. al., Appl. Microbiol., (1970), 20, 657. M i l l e r , T. L . and Johnson, M. J. Biotechnol. Bioeng., (1966), 8, 567. G u i l l e t , J., "Polymers and Ecological Problems", G u i l l e t , E d . , 45, Plenum Press, Ν . Y., 1973. Cooney, J. D. Colin Mater. Spec. Tech Scott, G. , Chem. i n Brit., (1973), 9, 267. G r i f f i n , G. J. L., Ger., (1973), 2333440. Bailey, W., "Proc. 3rd Int. Biodegradation Symp.", Sharpley and Kaplan, E d s . , 765, Applied Science Publishers, London, 1976. Gilbert, S. G . , Giacin, K. J., Van Gordon, T., Vahidi, A. and Giacin, J. R. Coating and Plastics Reprints, (1974), 34, 114. Kim, S. L., Diss. Abstr. Int. B., (1974), 35, 1121. Kim, S., Stannett, V. and Gilbert, R. D., J. Polym. Sci. Polym. L e t t . , (1973), 11, 731. S. J. Huang, J. P. B e l l , J. R. Knox, el. al.,"Proc. 3rd Int. Biodegradation Symp.", Sharpley and Kaplan, E d s . , 731, Applied Science Publishers, London, 1976. S i n c l a i r , R. G . , Environ. S c i . Technol., (1973), 7, 955.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

6 Reaction of W o o d Pulp with α,β-Amic Acids I. Synthesis of Possible Spinnable Derivatives LARRY C. WADSWORTH and JOHN A. CUCULO Fiber and Polymer Science Program, Department of Textile Chemistry, North Carolina State University, Raleigh, NC 27607

In view of the shortag petrochemical for the production of synthetic fibers, i t is no surprise that renewed emphasis is being placed on cellulose chemistry, a field which has received sagging interest for the past twenty years. In the coming years, our oil reserves w i l l become increasing­ ly scarce, or nonexistent, but cellulose is today, and in the future w i l l remain the most abundant of raw materials. But far more important, cellulose is a continually replaceable raw material (1). Trees or other plants currently under study, can be replanted as soon as existing mature trees are consumed. The rotation cycle for pulp can be as little as 15 years or even less (2). Granted that greater use of cellulose as a source of textile fibers could mean lesser or minimal dependence upon petrochemicals, fabrics made from cellulosics such as rayon and cotton have great aes­ thetic appeal, primarily greater wearing comfort due to the inherent hydrophylic properties of cellulose. Yet, the production of rayon in the United States and elsewhere is decreasing largely because of the unfavor­ able economics of meeting pollution standards and from competition with other fibers (3). An alternative to the viscose process has been proposed by Cuculo (4) through the reaction of cellu­ lose with amic acids. The product envisioned is a cellulose half-acid ester. Limited solubility of the derivatives has been obtained in dilute a l k a l i . With increasing degree of substitution (DS), the solubility of the cellulose half-acid ester should go through a transition of insolubility to solubility in dilute a l k a l i , water, water-alcohol mixtures, hydrocarbon81

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

a l c o h o l m i x t u r e s , and f i n a l l y , o r g a n i c s o l v e n t s , sim­ i l a r t o t h e t r a n s i t i o n d e s c r i b e d b y P e t e r s (_5) f o r cellulose ethers. The e s t e r p a r t o f t h e d e r i v a t i v e , h o w e v e r , w o u l d be s u b j e c t t o s a p o n i f i c a t i o n i n aqueous a l k a l i , d e p e n d e n t upon a l k a l i c o n c e n t r a t i o n and temper­ a t u r e and d e r i v a t i v e s t r u c t u r e . I d e a l l y t h e c e l l u l o s e h a l f - a c i d e s t e r c o u l d be c o n v e r t e d i n t o a w a t e r s o l u b l e s a l t , and wet extruded as a f i b e r , o r f i l m i n t o an a c i d , o r o t h e r non-solvent coagulating bath. T h i s procedure o f f e r s the advan­ t a g e o f a l l o w i n g c o n d i t i o n s t o be c h o s e n f o r p r e v e n t ­ i n g s a p o n i f i c a t i o n of the d e r i v a t i v e d u r i n g the solub­ i l i z a t i o n s t e p , t h e r e b y o p e n i n g up many p o s s i b i l i t i e s for producing c e l l u l o s i e r t i e s , s i n c e many a m i d e s i r e d p r o p e r t i e s c a n be u t i l i z e d . One important a p p l i c a t i o n c o u l d be t h e p r o d u c t i o n o f i n h e r e n t l y f l a m e - r e t a r d a n t f i b e r by r e a c t i n g c e l l u l o s e w i t h a m i c a c i d d e r i v a t i v e s c o n t a i n i n g bromine or phosphorous. Y e t , t h e p r o d u c t i o n o f s u f f i c i e n t l y h i g h DS c e l l u l o s e a c i d e s t e r to produce wet-spinnable d e r i v a ­ t i v e n e e d n o t be a l i m i t a t i o n f o r t h e r e a c t i o n . A f o u r - f o l d i n c r e a s e i n w a t e r a b s o r b e n c y (6) h a s b e e n o b t a i n e d i n the r e a c t i o n o f rayon f a b r i c with s u c c i n a m i c a c i d w i t h a DS o f 0.3. R e s e a r c h i s now i n p r o ­ g r e s s i n which amic a c i d s c o n t a i n i n g bromine are being r e a c t e d with c e l l u l o s i c f a b r i c s f o r the produc­ t i o n o f f l a m e - r e t a r d a n t f a b r i c s (7) · T h i s has a l r e a d y been demonstrated i n the l a b o r a t o r y f o r the l a t t e r case. The p o t e n t i a l s f o r m o d i f y i n g nonwovens by t h i s method are a l s o q u i t e f a s c i n a t i n g . F o r e x a m p l e , wood p u l p c o u l d be r e a c t e d w i t h a m i c a c i d s p r i o r t o nonwoven f a b r i c p r o d u c t i o n t o p r o d u c e h i g h l y a b s o r b e n t p a d d i n g and b a c k i n g m a t e r i a l s . In the p r e s e n t work, d e g r e e s o f s u b s t i t u t i o n r a n g i n g f r o m 0.3 t o 0.7 w e r e o b t a i n e d i n t h e r e a c t i o n o f v a r i o u s wood p u l p s r a n g i n g f r o m h i g h t o low d e g r e e s o f p o l y m e r i z a t i o n (DP) w i t h s u c c i n a m i c a c i d , ammonium succinamate, and Ν , Ν - d i e t h y l s u c c i n a m i c a c i d i n p a d bake r e a c t i o n s . R a t h e r l o w DS v a l u e s (DS a p p r o x i ­ m a t e l y 0.1) w e r e o b t a i n e d i n t h e B a r r a t t e - t y p e r e a c t ­ i o n s o f d r y and " n e v e r - d r i e d " wood p u l p s w i t h s u c c i n ­ amic a c i d . S t r u c t u r a l p r o o f o f the c e l l u l o s e hemis u c c i n a t e d e r i v a t i v e was o b t a i n e d b y i n f r a r e d a n a l y s i s . DP d e t e r m i n a t i o n s a c c o m p a n i e d a l l DS a n a l y s e s s o t h a t r e a c t i o n c o n d i t i o n s c o u l d be a p p r o p r i a t e l y v a r i e d t o o b t a i n h i g h d e g r e e o f s u b s t i t u t i o n w i t h minimum degra­ dation.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

6.

WADSWORTH

AND

cucuLO

Wood ΡύΙρ-α,β-Amic

Acid Reactions

83

Experimental R e a c t a n t s . S u c c i n a m i c a c i d was s y n t h e s i z e d f r o m s u c c i n i c anhydride as d e s c r i b e d by A l l e n ( 8 ) . Ammonium s u c c i n a m a t e was s y n t h e s i z e d f r o m succinamic acid. S u c c i n a m i c a c i d , 500 g , was d i s ­ p e r s e d i n acetone t o a t o t a l volume o f 2 ^ i n a 4 % beaker. T h e s u c c i n a m i c a c i d was s l i g h t l y s o l u b l e i n acetone. Ammonia g a s was s l o w l y b u b b l e d t h r o u g h t h e r e a c t i o n m e d i a f o r 2 1/2 h o u r s w i t h c o n t i n u o u s stirring. T h e r e a c t i o n was s l i g h t l y e x o t h e r m i c , b u t r e q u i r e d no e x t e r n a formed were f i l t e r e u t e s w i t h a c e t o n e w i t h o u t vacuum, a n d f i l t e r e d d r y under s u c t i o n . T h e p r o c e d u r e was r e p e a t e d t w o t i m e s , and t h e c r y s t a l s were s p r e a d o u t i n a t r a y t o d r y . A 9 5 % y i e l d was o b t a i n e d . P u r i t y and i d e n t i f i c a t i o n w e r e d e t e r m i n e d by m e l t i n g p o i n t (109° t o 110°C) a n d infrared analysis. Ν , Ν - d i e t h y l s u c c i n a m i c a c i d was s y n t h e s i z e d f r o m s u c c i n i c a n h y d r i d e b y Bowman (9). Ν,N-diethylamine, 55 m l , f r o m M a t h e s o n C o . , I n c . was p u r i f i e d b y s i m p l e distillation. S u c c i n i c a n h y d r i d e was o b t a i n e d f r o m Armageddon C h e m i c a l Co. T h e a m i n e was d i s s o l v e d i n 40 m l o f a c e t o n e ( F i s h e r L a b o r a t o r y G r a d e ) a n d a d d e d t o a s u s p e n s i o n o f 100 g r a m s o f a n h y d r i d e i n 100 m l o f acetone. T h e r e a c t i o n was i n i t i a l l y e x o t h e r m i c (max­ imum t e m p e r a t u r e 4 0 ° C ) . T h e s o l u t i o n was e v a p o r a t e d to near dryness. T o r e m o v e t h e y e l l o w t i n t , 100 m l o f a c e t o n e a n d a p p r o x i m a t e l y 2 g o f N o r i t e B, d e c o l o r i ­ z i n g carbon were added and t h e m i x t u r e h e a t e d t o a boil. T h e m i x t u r e was a l l o w e d t o s t e e p f o r a b o u t f i v e m i n u t e s , a n d f i l t e r e d warm t o y i e l d a c l e a r s o l u t i o n . T h e f i l t e r e d s o l u t i o n was t h e n h e a t e d t o a b o i l a n d c a r b o n t e t r a c h l o r i d e was a d d e d t o t h e p o i n t o f i n c i p i ­ ent t u r b i d i t y . F i n a l l y t h e s o l u t i o n was c o o l e d i n t h e f r e e z e r , and t h e r e s u l t i n g c r y s t a l s were f i l t e r e d , and s p r e a d o u t i n a t r a y t o d r y . A n 8 1 % y i e l d was o b t a i n ­ ed. P u r i t y and i d e n t i t y were d e t e r m i n e d by m e l t i n g p o i n t (82° t o 8 4 ° C ) a n d b y i n f r a r e d a n a l y s i s . C e l l u l o s e Source. The f o l l o w i n g d i s s o l v i n g p u l p s were o b t a i n e d from ITT R a y o n i e r , I n c . i n d r y s h e e t form w i t h the i n t r i n s i c v i s c o s i t i e s (I.V.) s p e c i f i e d i n d l / g : Rayocord-X-F, I.V.-9.2; C e l l u n i e r - F , I.V.3.72; R a y s e l e c t - J , I . V . - 3 . 3 2 . A l l were S o u t h e r n P i n e and p u l p e d by the S u l f i t e P r o c e s s ( 1 0 ) .

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" N e v e r - d r i e d " C e l l u n i e r - P (Hemlock) and d r i e d " C e l l u n i e r - F (Southern P i n e ) were a l s o from ITT R a y o n i e r (11).

"neverobtained

Pretreatment Conditions. The d r y p u l p s h e e t s , a s r e c e i v e d , w e r e f i r s t s h r e d d e d w i t h w a t e r i n a commer­ c i a l b l e n d e r a t h i g h s p e e d f o r 90 s e c o n d s . The p u l p s l u r r y was t h e n p o u r e d i n t o a B u c h n e r f u n n e l , a n d suction applied. P u l p w h i c h was n o t t o b e m e r c e r i z e d was t h e n w a s h e d f o r f i v e m i n u t e s w i t h a c e t o n e b e f o r e s u c t i o n was a p p l i e d . T h i s s t e p was r e p e a t e d t w i c e , and t h e p u l p s p r e a d o u t on aluminum f o i l , and a i r d r i e d a t room t e m p e r a t u r e The m o i s t u r e c o n t e n t o f t h e p u l p s t o be m e r c e r i z e sodium hydroxide c o n c e n t r a t i o c o u l d be p r e p a r e d t o r e s u l t i n an e q u i l i b r i u m v a l u e o f 17.5% t o compensate f o r t h e d i l u t i o n e f f e c t o f t h e wet p u l p . The s a m p l e s w e r e p l a c e d i n t h e r e f r i g e r a t o r a t 7 . 5 ° C f o r 24 h o u r s . The m e r c e r i z e d c e l l u l o s e was t h e n w a s h e d f r e e o f c a u s t i c a n d a c i d i f i e d w i t h 10% acetic acid. A f t e r washing free of a c i d , the c e l l u ­ l o s e was a c e t o n e w a s h e d a n d a i r - d r i e d . B o t h the " n e v e r - d r i e d " p u l p s were s u l f i t e p u l p e d and were a c i d i c t o l i t m u s paper. As soon as r e c e i v e d , t h e p u l p s were washed w i t h w a t e r on a B u c h n e r f u n n e l . The w a s h i n g s w e r e r e p e a t e d u n t i l the f i l t r a t e was d e t e r m i n e d n e u t r a l by a y e l l o w t o b l u e c o l o r change when one d r o p o f 0.1N NaOH a n d two d r o p s o f a 0.1% s o l u t i o n o f b r o m o c r e s o l p u r p l e i n d i c a t o r were added t o 100 m l o f f i l t r a t e . P o r t i o n s o f b o t h wet, neutralized p u l p s were s e a l e d i n p o l y e t h y l e n e bags and p l a c e d i n the r e f r i g e r a t o r u n t i l ready f o r use. Portions of b o t h w e t , n e u t r a l i z e d p u l p s , 250 g r a m s (approximately 6:1 w a t e r t o p u l p c o n t e n t ) , w e r e f u r t h e r w a s h e d t h r e e times each w i t h methanol, e t h a n o l , i s o p r o p a n o l , and acetone. T h e p u l p s w e r e t h e n a i r - d r i e d a t r o o m temp­ erature. Nonwoven Mat F o r m a t i o n . A c y c l i n d r i c a l handsheet m o l d (6 i n χ 16 i n ) was u t i l i z e d t o make t h e c e l l u l o s e mats. A r o u n d f i b e r g l a s s s c r e e n was c u t s l i g h t l y l a r g e r than the handsheet mold d i a m e t e r and p l a c e d on­ t o t h e mat f o r m i n g s c r e e n o f t h e m o l d . The cylinder was f i l l e d w i t h w a t e r a n d 1 g r a m o f c e l l u l o s e w h i c h had been shredded i n a commercial b l e n d e r a t h i g h speed f o r 90 s e c o n d s , was a d d e d . The w a t e r - c e l l u l o s e s l u r r y was a g i t a t e d , t h e l o w e r w a t e r v a l v e t o t h e m o l d o p e n e d , a n d a u n i f o r m c e l l u l o s e mat was f o r m e d o n t h e f i b e r g l a s s s c r e e n w i t h a w e i g h t o f 1.62 oz/yd (707 g r n / y d ^ ) 2

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

6. wADswoRTH

AND CUCULO

Wood ΈύΙρ-^,β-Amic

Acid Reactions

85

A n o t h e r f i b e r g l a s s s c r e e n was p l a c e d o n t o p o f t h e c e l l u l o s e m a t t o f o r m a s a n d w i c h a n d was t h e n r e m o v e d from t h e mold. Amic A c i d T r e a t m e n t S o l u t i o n s . Succinamic acid p a d b a t h s were p r e p a r e d by d i s s o l v i n g 54% s u c c i n a m i c a c i d o n t h e w e i g h t o f t h e s o l u t i o n (o.w.s.) i n d e i o n i z e d d i s t i l l e d water. H e a t was r e q u i r e d t o m a i n ­ t a i n s u c c i n a m i c a c i d s o l u b i l i t y (90°C + 5 ° C ) . When c a t a l y s t was u t i l i z e d , 1.62% ammonium s u l f a m a t e (o.w.s.) was a d d e d t o t h e b a t h . Succinamic acid s o l ­ u t i o n s w e r e p r e p a r e d i n t h e same m a n n e r f o r t h e Baratte reactions. T h e a q u e o u s ammoniu p r e p a r e d by d i s s o l v i n d e i o n i z e d d i s t i l l e d w a t e r , and h e a t i n g t o 85°C + 5 ° C . When s p e c i f i e d , 1.62% ammonium s u l f a m a t e c a t a l y s t (o.w.s.) was a d d e d . The m e l t b a t h s were p r e p a r e d , s i m p l y b y h e a t i n g ammonium s u c c i n a m a t e t o s l i g h t l y above i t s m e l t i n g p o i n t o f 110°C. T h e Ν , Ν - d i e t h y l s u c c i n a m i c a c i d m e l t p a d b a t h was p r e p a r e d by h e a t i n g t o s l i g h t l y above i t s m e l t i n g p o i n t o f 84°C. Pad-Bake T e c h n i q u e . The h a n d s h e e t sandwiches were s t a p l e d around t h e c i r c u m f e r e n c e t o c o n f i n e t h e c e l l u l o s e mat. A f t e r a n i m m e r s i o n t i m e o f 90 s e c o n d s a t t h e s p e c i f i e d p a d t e m p e r a t u r e , t h e h a n d s h e e t was r e m o v e d , b l o t t e d b e t w e e n two p u l p s h e e t s , a n d squeezed between pad r o l l s t o a p i c k u p r a t i o o f a p p r o x i m a t e l y 4 t o 1. The s a m p l e s were i m m e d i a t e l y p l a c e d i n a p l a s t i c bag a f t e r p a d d i n g t o keep them wet u n t i l t h e e n t i r e s e r i e s was p a d d e d ( n o t l o n g e r t h a n 20 m i n u t e s ) . The samples were t h e n suspended w i t h p a p e r c l i p s on a r i n g s t a n d w h i c h was i m m e d i a t e l y p l a c e d i n t o t h e o v e n . The b a k e o v e n was r a i s e d t o 3 ° C a b o v e t h e s p e c i f i e d b a k e temperature t o a l l o w f o r temperature drop d u r i n g t h e o p e n i n g and c l o s i n g o f t h e oven door, and t h e c o o l i n g e f f e c t c a u s e d by t h e h e a t i n g o f t h e m e t a l r i n g s t a n d . T h r o u g h o u t t h e b a k e r e a c t i o n s , t h e t e m p e r a t u r e was m a i n t a i n e d a t t h e s p e c i f i e d t e m p e r a t u r e + 3°C. The o v e n was a P r e c i s i o n S c i e n t i f i c Company 1 I s o t e m p with forced a i r draft. B a r a t t e r e a c t i o n s were p e r f o r m e d i n a B u c h i Rotavapor. T e n grams o f p u l p w e r e p l a c e d i n t o a 500 m l r o u n d b o t t o m f l a s k a n d 100 grams o f s h o r t g l a s s r o d s ( a p p r o x i m a t e l y 1.5 χ 1.0 cm) w e r e a d d e d t o t h e f l a s k t o enhance u n i f o r m t u m b l i n g o f t h e p u l p throughout t h e reaction. When B a r a t t e r e a c t i o n s w e r e p e r f o r m e d o n " n e v e r - d r i e d " p u l p s , s u f f i c i e n t w e t p u l p was u t i l i z e d

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

86

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

t o b e e q u i v a l e n t t o 10 g r a m s o f d r y p u l p . The a m i c a c i d s o l u t i o n s were t h e n added t o t h e f l a s k , and t h e f l a s k was r o t a t e d i n a s i l i c o n e o i l b a t h m a i n t a i n e d at the temperature corresponding to t h a t of the e q u i v a l e n t pad s o l u t i o n i n the pad-bake r e a c t i o n s , f o r a p e r i o d o f 15 m i n u t e s t o a l l o w f o r s u f f i c i e n t s a t u r ­ a t i o n o f the s u b s t r a t e w i t h the amic a c i d . Than a second o i l bath at the s p e c i f i e d r e a c t i o n temperature was p l a c e d u n d e r t h e r o t a t i n g f l a s k . Experimental Analyses. The d e t e r m i n a t i o n o f p e n d e n t c a r b o x y l i c a c i d c o n t e n t by t h e i o n - e x c h a n g e r e a c t i o n between c a l c i u m a c e t a t e and t h e c a r b o x y l i c a c i d g r o u p s , and t h c a r b o n y l and e s t e r m e t h o d h a v e b e e n p r e v i o u s l y d e s c r i b e d (8) . In a d d i t i o n to d e t e r m i n i n g the c a r b o x y l i c a c i d c o n t e n t by t h e c a l c i u m a c e t a t e m e t h o d u s i n g C r a m e r ' s c o r r e c t i o n f a c t o r (S, 12), f r e e c a r b o x y l c o n t e n t was a l s o determined by the cation-exchange reaction between the s i l v e r c a t i o n and the c a r b o x y l p r o t o n a s d e s c r i b e d b y D a v i d s o n a n d N e v e l (13) w i t h t h e e x c e p t i o n t h a t the volume o f s i l v e r meta-nitrophenolate t r e a t m e n t s o l u t i o n was i n c r e a s e d f r o m 100 t o 300 ml. The c a l c u l a t i o n s o f f r e e , t o t a l , and c r o s s l i n k degrees o f s u b s t i t u t i o n were performed u s i n g the f o r m u l a s d e v e l o p e d by J o h n s o n , e t a l . ( 1 4 ) . I n t r i n s i c v i s c o s i t i e s were d e t e r m i n e d on t h e s a p o n i f i e d d e r i v a t i v e s u s i n g ASTM P r o c e d u r e D1795-62 (15), and degrees o f p o l y m e r i z a t i o n were c a l c u l a t e d u s i n g t h e Mark-Houwink e q u a t i o n and t h e Κ and a v a l u e s o f Newman, et. a l . (16) . N i t r o g e n a n d s u l f u r a n a l y s e s w e r e p e r f o r m e d b y an independent l a b o r a t o r y u s i n g the f l a s h combustion t e c h n i q u e a n d t h e S c h o n i g e r t e s t f o r t h e two a n a l y s e s , respectively. I n f r a r e d a n a l y s e s o f t h e wood p u l p s a n d d e r i v a t i ­ ves were p e r f o r m e d w i t h p o t a s s i u m bromide p e l l e t s u t i l i z i n g a P e r k i n E l m e r 337 G r a t i n g I n f r a r e d S p e c t r o ­ photometer. A W i l e y m i l l was u t i l i z e d t o d i s i n t e g r a t e t h e p u l p t o a i d i n t h e p r e p a r a t i o n o f more u n i f o r m pellets. The r e g e n e r a t e d c e l l u l o s e f i l m s w e r e s i m p l y run without f u r t h e r p r e p a r a t i o n . Results

and

Discussion

Reactants. The s t r u c t u r e s o f t h e a , 3 - a m i c a c i d s r e a c t e d w i t h wood c e l l u l o s e a r e g i v e n i n T a b l e I . D e g r a d a t i o n o f t h e c e l l u l o s e c h a i n i s shown i n t h i s

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

6.

WADSWORTH

AND CUCULO

Wood Pulp-afi-Amic

Acid Reactions

87

paper to occur i n the r e a c t i o n of c e l l u l o s e with succinamic a c i d , p a r t i c u l a r l y i n the presence o f ammonium s u l f a m a t e c a t a l y s t . I t was t h e o r i z e d t h a t d e g r a d a t i o n c o u l d be m i n i m i z e d by r e a c t i n g c e l l u l o s e u n d e r t h e more a l k a l i n e c o n d i t i o n s e f f e c t e d by t h e u s e o f ammonium s u c c i n a m a t e r e a c t a n t . Ν,N-diethyl s u c c i n a m i c a c i d was s e l e c t e d t o e l i m i n a t e a competing i m i d e s i d e r e a c t i o n (1J) and t h e r e b y i n c r e a s e s t h e amount o f p r o d u c t c o n v e r t e d t o c e l l u l o s e h a l f - a c i d ester. r

Infrared Analyses of Cellulose Hemisuccinate Derivatives. The m a i n p r o d u c t o f t h e r e a c t i o n i s a cellulose half-aci ammonia: ^NH Cell-OH

2

OH.

+ 0 = C

Cell

- 0 - C

.C

C - O H +

=

Ο

NH^

*

The mechanism o f t h e r e a c t i o n s w i t h a l c o h o l s i s t h o u g h t t o i n v o l v e a c y c l i c a n h y d r i d e i n t e r m e d i a t e (18, 1 9 , 20) a n d was t h e s u b j e c t o f a r e c e n t Ph.D. disser­ t a t i o n (Γ7) . The i n f r a r e d s p e c t r u m o f a c e l l u l o s e h e m i s u c c i n a t e produced from the r e a c t i o n o f m e r c i z e d Rayocord-X-F wood p u l p w i t h s u c c i n a m i c a c i d i s shown i n c u r v e A o f F i g u r e l a . T h e number o f s u c c i n i c a c i d g r o u p s p e r a n h y d r o g l u c o s e u n i t as e x p r e s s e d by t h e f r e e DS i s _^ 0.38. The b r o a d a b s o r p t i o n p e a k c e n t e r e d a t 3400 cm i s t y p i c a l o f t h e OH s t r e t c h i n g a s s i g n e d t o c e l l u l o s e . The s h a r p e r a b s o r p t i o n b a n d a t 2900, a l s o a s s i g n a b l e t o c e l l u l o s e , i s due t o CH s t r e t c h i n g (_21) . The s t r o n g a b s o r p t i o n p e a k a t 1720 c m " which i s not o b s e r v e d i n n a t i v e c e l l u l o s e i s due t o t h e o v e r l a p o f t h e c a r b o x y l c a r b o n y l and t h e e s t e r c a r b o n y l . If t h i s i s t r u l y the s t r u c t u r e , then c o n v e r t i n g the pendant c a r b o x y l group i n t o a c a r b o x y l a t e anion should r e s u l t i n the r e s o l u t i o n o f the s i n g l e peak i n t o two peaks w i t h the c a r b o x y l a t e anion a b s o r b i n g a t lower energy, thereby p r o v i d i n g p r o o f o f s t r u c t u r e . This i s 1

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

88

Table

TEXTILE

I.

A N D PAPER

CHEMISTRY

A N D TECHNOLOGY

Reactants OH

Succinamic

acid

NH

\C = 0

0 = C CH

2

- CH

2

V*)

Ammonium

ο - c

succinamate

\C

\ ,0H

Ν,Ν-diethyl s u c c i n a m i c

acid

0

= 0

N(CH.CH,).

β=

= c C H - CH

Figure la. IR spectra: (A) cellulose hemisuccinate; (B) sample A washed with 10% sodium bicarbonate; (C) sample A saponified

3500

ο

2

3000 2500 2000 Frequency, cm" 1

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

1500

6.

WADSWORTH AND

3500

3000

Wood Pulp-aft-Amic Acid Reactions

cucuLO

2500

Figure lb. IR spectra of Rayselect-J pulp reacted with (D) succinamic acid, (E) ammonium succinamate, and (F) N,Ndiethyl succinamic acid

2000

Frequency, cm"

1

3500

3000

2500

2000

Frequency, cm"

1

1500

Figure lc. IR spectra of (G) mercerized, untreated Ray select-], (H) film regenerated from Rayselect-J plus succinamic acid reactant, (I) film regenerated from Rayselect-J plus ammonium succinamate

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

90

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

confirmed i n curve Β i n which the d e r i v a t i v e was w a s h e d w i t h 10 p e r c e n t s o d i u m b i c a r b o n a t e . T h i s same e f f e c t h a s b e e n shown w i t h c e l l o p h a n e r e a c t e d w i t h s u c c i n a m i c a c i d (3/7)· I n t h e c u r v e C, t h e a b s o r p t i o n s p e c t r a a f t e r s a p o n i f i c a t i o n o f t h e d e r i v a t i v e by t h e m o d i f i e d E b e r s t a d t m e t h o d i s s h o w n ( 1 2 , 22), and i s i d e n t i c a l t o t h a t of pure c e l l u l o s e . The p e a k a t 1635 i s due t o a b s o r b e d w a t e r ( 2 1 ) . C u r v e s D, E , a n d F ( F i g u r e l b ) r e p r e s e n t m e r c e r ­ ized Rayselect-J reacted with succinamic acid with c a t a l y s t , ammonium s u c c i n a m a t e w i t h o u t c a t a l y s t , a n d Ν,Ν-diethyl succinamic a c i d r e s p e c t i v e l y . A l l three curves appear i d e n t i c a l which o f f e r s s t r o n g support t h a t the three r e a c t a n t hemisuccinate derivative C u r v e G, F i g u r e l c , i s t h e IR s p e c t r u m o f m e r c e r ­ ized, unreacted Rayselect-J pulp. C u r v e s H and I a r e s p e c t r a o f c e l l u l o s e f i l m s f o r m e d by d i s s o l v i n g t h e c e l l u l o s e - h e m i s u c c i n a t e d e r i v a t i v e s i n 10% s o d i u m h y d r o x i d e a t - 1 0 ° C , and c o a g u l a t i n g t h e c e l l u l o s e by the a d d i t i o n of acetone. The r e a c t a n t s f r o m w h i c h the c e l l u l o s e - h e m i s u c c i n a t e d e r i v a t i v e s were formed p r i o r t o s o l u b i l i z a t i o n and s u b s e q u e n t r e g e n e r a t i o n o f c e l l u l o s e w e r e s u c c i n a m i c a c i d a n d ammonium s u c c i n a m a t e , c u r v e s H and I , r e s p e c t i v e l y . T h e s e two s p e c t r a are i d e n t i c a l t o t h a t o f pure c e l l u l o s e , c u r v e G, a n d i t i s no s u r p r i s e t h a t t h e d e r i v a t i v e s a r e s a p o n i f i e d i n t h e 10% s o d i u m h y d r o x i d e . E f f e c t o f Treatment C o n d i t i o n s . From t h e p h o t o ­ g r a p h s i n F i g u r e 2, i t c a n b e s e e n t h a t t h e m e r c e r ­ i z e d c e l l u l o s e h a n d s h e e t has a more o p e n t e x t u r e and i s l e s s m a t t e d down t h a n i s t h e same w e i g h t o f u n m e r c e r i z e d R a y o c o r d - X - F wood p u l p . I t was shown t h a t the mercerized c e l l u l o s e r e s u l t e d i n almost twice the d e g r e e o f s u b s t i t u t i o n as was o b t a i n e d w i t h u n m e r c e r ized cellulose. T h e e f f e c t s o f t h e v a r i o u s p r e t r e a t m e n t s t a g e s as w e l l as t h e s u b s e q u e n t b a k i n g , and s a p o n i f i c a t i o n and a c i d n e u t r a l i z a t i o n o f t h e pad-bake c o n t r o l s are depicted i n Table I I . O v e r a l l , none o f t h e p r e t r e a t m e n t s g i v e n t h e wood p u l p s h a d a n y n o t a b l e e f f e c t on I . V . , o r DP as c a l c u l a t e d f r o m I . V . Baking without r e a c t a n t a t 1 8 0 ° C f o r 15 m i n u t e s a n d s a p o n i f i c a t i o n f o l l o w e d by a c i d n e u t r a l i z a t i o n r e s u l t e d i n o n l y m i n o r r e d u c t i o n o f DP v a l u e s . T h e n e g a t i v e DS v a l u e s o b t a i n e d a r e t o b e e x p e c t ­ ed f o r u n t r e a t e d p u l p . The f o r m u l a s u s e d i n c a l c u l a t ­ i n g t h e DS v a l u e s make t h e a s s u m p t i o n t h a t no s u b ­ s t i t u e n t other than c e l l u l o s e h a l f - a c i d e s t e r or the

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

Pad-bake controls

13 14 15 16 17 18

13 14 15 16 17 18

X X X X X X

a

-0.01

-0.01

-0.03

1184 1249 1235 1196 1070 931 547 558 559 544 520 481 633 654 730 667 589 557

3.23 3.29 3.30 3.21 3.07 2.84 3.74 3.86 4.31 3.94 3.48 3.29

DP

6.98 7.37 7.29 7.06 6.32 5.49

Experimental data Total

B.

0.02

0.00

0.00

Free

Handsheet

Conditions

Λ

C

Shredded"

I.V.,dl/g

received

A s

-0.05

-0.01

-0.01

Crosslink

Baked 180°C/15 mln

Sap on. / a c i d neut.

Shredded with water i n a commercial blender at high speed f o r 90 seconds,

d

DP calculated from Mark-Houwink equation using the k and a values of Newman, Loeb, and Conrad (16).

i n t r i n s i c v i s c o s i t y determined by ASTM Procedure 1795-62.

b

"Vy7hëëts"as received from ITT Rayonier, Inc. were prepared f o r I n t r i n s i c v i s c o s i t y determination according to ASTM Procedure D1795-62.

9 10 11 12

7 8 9 10 11 12

Sample designation Ravocord-X-F Rayselect-J Cellunler-F

Table I I .

CO

Ci

§

δι

Ci

i.

•to

Ο Ο

i

η

i

Ο

Ο

>

92

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

t h e c r o s s l i n k segment i s p r e s e n t on t h e s u b s t r a t e . C r o s s l i n k i n g DS was d e t e r m i n e d b y t h e a m o u n t b y w h i c h t h e t o t a l s a p o n i f i c a t i o n e q u i v a l e n t was g r e a t e r t h a n twice the pendant c a r b o x y l d e t e r m i n a t i o n (Γ4). Thus, a t v e r y l o w d e g r e e s o f r e a c t i o n , o r w i t h no r e a c t i o n a s w i t h t h e c o n t r o l s , n e g a t i v e DS v a l u e s a r e l i k e l y t o be e n c o u n t e r e d b e c a u s e any e x p e r i m e n t a l e r r o r s a r e g r e a t l y m a g n i f i e d by t h o s e b u i l t - i n a s s u m p t i o n s . The e f f e c t o f bake t i m e a t bake t e m p e r a t u r e s r a n g i n g f r o m 1 5 0 ° C t o 1 8 0 ° C i s shown i n F i g u r e 3. DS i n c r e a s e s w i t h temperature, but l e s s d r a s t i c a l l y be­ yond 160°C. W i t h a l l t e m p e r a t u r e s , DS a p p e a r s t o l e v e l o f f a t i n t e r m e d i a t e b a k e t i m e s o f 20 m i n u t e s from 150°C t o 170° similar levelling-of was s h o w n b y C u c u l o (6) i n the reaction of succinamic a c i d w i t h r a y o n f a b r i c , a n d b y J o h n s o n (_23) a f t e r t h r e e minutes a t 170°C. T h e e f f e c t s o f t r e a t m e n t c o n d i t i o n s o n DS a n d DP a r e g i v e n i n T a b l e I I I . T h r e e wood p u l p s w e r e u t i ­ l i z e d a n d some e x p e r i m e n t s w e r e p e r f o r m e d i n two t o f i v e s e p a r a t e t r i a l s , e f f e c t i n g many r e p l i c a t i o n s o f t h e same c o n d i t i o n s . T h e f r e e DS v a l u e s i n s a m p l e s 19-23 d i f f e r v e r y l i t t l e ; h o w e v e r , t h e f i r s t two t o t a l DS v a l u e s a r e n o t a b l y l o w e r t h a n t h o s e o f s a m p l e s 21 t h r o u g h 23. The t o t a l s a p o n i f i c a t i o n e q u i ­ v a l e n t s o f s a m p l e s 19 a n d 20 w e r e d e t e r m i n e d b y t h e a l c o h o l i c a l k a l i m e t h o d (22^) i n w h i c h 95% e t h a n o l was u s e d as a s w e l l i n g a g e n t t o a i d i n t h e p e n e t r a t i o n o f sodium h y d r o x i d e , but i n a l l remaining experiments w a t e r was s u b s t i t u t e d f o r t h e e t h a n o l s i n c e i t was r e p o r t e d b y A l l e n (8) t h a t w a t e r was a b e t t e r s w e l l i n g a g e n t f o r t h e c e l l u l o s e h a l f - a c i d e s t e r t h a n was e t h a n o l , a l t h o u g h h e f o u n d no d i f f e r e n c e i n DS b y t h e s u b s t i t u t i o n of water f o r ethanol. E l i m i n a t i n g t h e c a t a l y s t i n s a m p l e s 24, 30 a n d 35, h a s n o d e t e c t a b l e e f f e c t i n t o t a l DS. Catalyst has b e e n r e p o r t e d t o d e c r e a s e t h e amount o f c r o s s l i n k i n g and s h i f t more o f t h e p r o d u c t t o t h e d e s i r e d h a l f - a c i d e s t e r (8) . C u c u l o (6) has f o u n d t h a t a c i d i c c a t a l y s t i n c r e a s e s t h e e x t e n t o f r e a c t i o n when s h o r t bake t i m e s and t e m p e r a t u r e s a r e u t i l i z e d . With the b a k e c o n d i t i o n s o f 1 8 0 ° C f o r 15 m i n u t e s e m p l o y e d i n t h i s work, h o w e v e r , t h e p r e s e n c e o f c a t a l y s t had no s i g n i f i c a n t e f f e c t o n t o t a l , f r e e o r c r o s s l i n k i n g DS. S a m p l e s 25 a n d 31 w e r e b o t h b a k e d a t 1 5 0 ° C f o r 22 m i n u t e s w i t h a c i d c a t a l y s t , a n d b o t h h a d l o w e r DS v a l u e s compared t o t h e a v e r a g e o f a l l t h e e x p e r i m e n t s a t 1 8 0 ° C f o r 15 m i n u t e s . S a m p l e s 26 a n d 32 w e r e n o t m e r c e r i z e d p r i o r t o t r e a t m e n t , a n d r e s u l t e d i n DS

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

6.

WADSWORTH AND CUCULO

Figure

2.

Handsheets

Wood Pulp-afi-Amic

of (a) unmercerized Rayocord-X-F cord-X-F

Acid Reactions

and (b) mercerized

93

Rayo-

0.35H

Bake time, min.

Figure 3. Free DS as a function of bake time and temperature in the reaction of Rayocord-X-F with succinamic acid with ammonium sulfamate catalyst

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

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6.

WADSWORTH AND CUCULO

Wood Pulp-afi-Amic

Acid Reactions

v a l u e s on t h e o r d e r o f a p p r o x i m a t e l y o n e - h a l f t h o s e o b t a i n e d on t h e m e r c e r i z e d p u l p s . Not surprisingly, t h i s s t r o n g l y i n d i c a t e s t h a t a c c e s s i b i l i t y c o u l d be t h e l i m i t i n g f a c t o r f o r DS. Wood p u l p s a m p l e n u m b e r 36 was p r e - w e t w i t h w a t e r (4:1 p i c k u p r a t i o ) p r i o r t o p a d d i n g t o d e t e r m i n e i f t h e wet s u b s t r a t e w o u l d r e s u l t i n i m p r o v e d p e n e t r a t i o n by t h e r e a c t a n t . When comp a r e d t o s a m p l e s 25 a n d 31 w h i c h r e c e i v e d t h e same treatment c o n d i t i o n s except b e i n g padded d r y , t h e r e w e r e no d i f f e r e n c e s i n DS v a l u e s . A l t h o u g h no b e n e f i t was d e r i v e d f r o m p a d d i n g t h e w e t s a m p l e i n t h i s p a r t i c u l a r c a s e , t h e f a c t t h a t t h e r e was no l o s s i n DS p r e s e n t s t h e a d v a n t a g e o f b e i n g a b l e t o r e a c t wet pulp, l i k e l y after pulping or mercerization T h e e f f e c t s o f t r e a t m e n t c o n d i t i o n s o n DP a r e v e r y s t r i k i n g i n T a b l e I I I when c o m p a r e d t o t h e u n treated control values i n Table I I . T h e DP o f R a y o c o r d - X - F was r e d u c e d f r o m 1196 i n t h e h a n d s h e e t t o an a v e r a g e v a l u e o f 321 a f t e r t r e a t m e n t . These samples w e r e b a k e d a t 1 8 0 ° C f o r 15 m i n u t e s , a n d r e s u l t e d i n a 73% d e c r e a s e i n c h a i n l e n g t h . U n d e r t h e same c o n d i t i o n s , a 66% d e c r e a s e i n DP r e s u l t e d w i t h R a y s e l e c t - J a n d a 62% d e c r e a s e w i t h C e l l u n i e r - F . Appreciable d e g r a d a t i o n a l s o o c c u r r e d a t t h e l e s s s e v e r e bake c o n d i t i o n s o f 1 5 0 ° C f o r 22 m i n u t e s . Removing t h e c a t a l y s t i n experiments 24, 30, a n d 35 r e s u l t e d i n n o t a b l y l e s s dégradation i n a l l t h r e e t r i a l s , without s i g n i f i c a n t l y a f f e c t i n g DS. H i g h DP v a l u e s a r e o b t a i n e d on p u l p s n o t m e r c e r i z e d p r i o r t o t r e a t m e n t , b u t t h e c o r r e s p o n d i n g DS v a l u e s a r e low. D e g r a d a t i o n was f i r s t s u s p e c t e d i n t h e work by n o t i n g sample d i s c o l o r a t i o n upon t r e a t m e n t . Normally, t h e more s e v e r e t h e t r e a t m e n t c o n d i t i o n s , t h e d a r k e r t h e brown d i s c o l o r a t i o n . S u b s e q u e n t w o r k w i t h ammonium succinamate r e a c t a n t l e d t o h i g h DS w i t h o n l y slight discoloration. The wood p u l p s t r e a t e d u n d e r s e v e r e l y d e g r a d i n g c o n d i t i o n s i n T a b l e I I I may b e a p p r o a c h i n g a l e v e l - o f f DP. A c c o r d i n g t o B a t t i s t a , e t a l . (_24) , l e v e l - o f f DP i s d e p e n d e n t upon t h e s e v e r i t y o f t h e d e g r a d a t i o n cond i t i o n s , a n d t h e y g i v e t h e a v e r a g e l e v e l - o f f DP o f b l e a c h e d s u l f i t e p u l p s as r a n g i n g f r o m 280 t o 200, w h i l e t h a t o f m e r c e r i z e d w o o d p u l p r a n g e s f r o m a DP o f 90 t o 70. L e v e l - o f f DP c e l l u l o s e h a s b e e n s h o w n t o e x h i b i t h i g h e r l a t e r a l o r d e r , and i t has been h y p o t h e s i z e d with s t r o n g s u p p o r t i n g evidence t h a t under a c i d h y d r o y l i s , t h e amorphous r e g i o n s a r e h y d r o l y z e d l e a v i n g o n l y t h e h i g h l y o r d e r e d and w e l l - d e f i n e d c r y s t a l l i n e r e g i o n s (2_4, 25) . Detailed structural analysis

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

96

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

by on be

X-ray o r o t h e r methods, have not y e t been performed the c e l l u l o s e h a l f - a c i d e s t e r d e r i v a t i v e , but w i l l the subject of future i n v e s t i g a t i o n s . T h e e f f e c t s o f t r e a t m e n t c o n d i t i o n s o n t h e DS and DP o f wood p u l p s r e a c t e d w i t h ammonium s u c c i n a m a t e and Ν,Ν-diethyl s u c c i n a m i c a c i d a r e g i v e n i n T a b l e IV. S a m p l e s 38 a n d 44 w e r e p a d d e d w i t h a q u e o u s ammonium s u c c i n a m a t e w i t h c a t a l y s t and b a k e d a t 1 5 0 ° C f o r 22 minutes. T h e f r e e DS v a l u e s o f t h e two w e r e 0.45 and 0.47 as c o m p a r e d t o 0.45 f o r the sample baked a t 180°C f o r 15 m i n u t e s . Thus, bake c o n d i t i o n s more s e v e r e t h a n t h e f o r m e r a p p e a r t o be u n n e c e s s a r y f o r ammonium succinamate. S a m p l e 45, w h i c h was p a d d e d w e t , ex­ hibited s l i g h t l y highe d i d s a m p l e 39 w h i c r e a c t i o n c o n d i t i o n s employed, the presence o f c a t a l y s t was o f l i t t l e significance. The p a d - b a k e r e a c t i o n s o f m e r c e r i z e d C e l l u n i e r - F w i t h ammonium s u c c i n a m a t e m e l t s y i e l d r a t h e r l o w DS v a l u e s when p a d d e d d r y a n d p r e - w e t w i t h w a t e r , r e s u l t ­ i n g i n f r e e DS v a l u e s o f 0.16 a n d 0.19, respectively. The l o w DS v a l u e s w e r e l i k e l y d u e t o p o o r p e n e t r a t i o n o f t h e r e a c t a n t s i n c e t h e ammonium s u c c i n a m a t e was rather viscous. Ν,Ν-diethyl succinamic a c i d d i d not r e a c t with e i t h e r o f t h e p u l p s when p a d d e d d r y ; h o w e v e r , when t h e c e l l u l o s e m a t s w e r e p r e - w e t w i t h w a t e r , DS v a l u e s o f 0.32 a n d 0.36 w e r e o b t a i n e d w i t h two d i f f e r e n t wood pulps. T h i s was t h e m o s t p r o n o u n c e d e f f e c t observed w i t h t h e r e a c t a n t by p r e w e t t i n g t h e s u b s t r a t e p r i o r to padding. Apparently with the b u l k i e r Ν,Ν-diethyl succinamic a c i d , pre-wetting of the substrate with w a t e r i s much m o r e i m p o r t a n t . As shown i n T a b l e V, t h e B a r a t t e r e a c t i o n o f Ν , Ν diethyl succinamic acid with mercerized Cellunier-F r e s u l t s i n a p p r o x i m a t e l y t h e same f r e e c a r b o x y l i c a c i d DS, 0.31, as i n t h e p a d - b a k e r e a c t i o n s . In t h i s B a r a t t e r e a c t i o n , t h e p u l p was p r e - w e t t o 500% m o i s ­ ture content p r i o r t o adding the melted Ν,Ν-diethyl s u c c i n a m i c a c i d , a n d t h e f l a s k was r o t a t e d o v e r a n o i l b a t h a t 1 4 5 ° C f o r 15 m i n u t e s b e f o r e a p p l y i n g t h e vacuum t o remove t h e w a t e r . Apparently pre-wetting t h e p u l p h a d t h e same b e n e f i c i a l e f f e c t s . Sample n u m b e r 51 was a l s o p r e - w e t , b u t was p l a c e d i n t h e o v e n a t 1 1 0 ° C f o r 38 h o u r s . F r e e DS t h e m o s t i m p o r t a n t p a r a m e t e r , was o n l y s l i g h t l y g r e a t e r t h a n t h a t o b t a i n ­ e d w i t h t h e B a r a t t e r e a c t i o n , b u t t h e t o t a l DS was much h i g h e r , a n d was r e f l e c t e d p r i m a r i l y i n i n c r e a s e d crosslinking.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

a

44 45 46 47 48 49

0.45 0.45 0.25 0.49 0.07 0.32

0.47 0.50 0.16 0.19 0.03 0.36

0.53 0.50 0.29 0.56 -0.02 0.32

0.52 0.58 0.18 0.19 0.04 0.36

a

DS Free

Total

B.

none

266

335

1.57 1.80 2.27 2.37 2.87 2.21 1.97 1.94 3.02 3.04 3.50 2.52

0.08 0.05 0.04 0.07 -0.09 0.00

0.05 0.08 0.02 0.00 0.01 0.00

329 511 515 592 428

305 385 401 486 374

DP

Experimental Data

none

X

none

X

X X

X X

Dry

I.V.,dl/g

Crosslink

X X

X X

N, N-diethyl melt N, N-diethyl melt

48 49

none

7

X X

X X

X X

X

1

X X X X none

X X X X X

X X X none

X X X X X

amm. succ. melt amm. succ. melt

succ. succ. succ. succ. succ.

46 47

45

amm. amm. amm. amm. amm.

61.9% 61.9% 61.9% 61.9% 61.9%

44

Catalyst

Handsheet

Merc.

Shredded

Conditions

Carboxyl content determined by absorption of s i l v e r from s i l v e r meta-nitrophenolate solutions

38 39 40 41 42 43

42 43

AO 41

38 39

Reactant

A.

(13).

Padded

Pad-bake reactions of wood pulps with ammonium succinamate and N, N-dlethyl succinamic acid

Sample designation Rayselect-J Cellunier-F

Table IV.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

C

592

3.50

0.00

0.08

0.10

none

none X X X X

e

Carboxyl content determined by calcium acetate method (8,12).

f

forced into r o t a t i n g f l a s k during r e a c t i o n .

Steam

Reaction performed under r e f l u x conditons, no nitrogen, no vacuum.

Stream of nitrogen gas forced into r o t a t i n g f l a s k throughout r e a c t i o n , aspirator vacuum applied.

e

C

P u l p saturated with amic acid i n Erlenmeyer f l a s k , heated 110 C f o r 38 hours.

DP 462 267 602 563 560 620 618

Experimental data I.V.,dl/g 2.72 1.57 3.55 3.32 3.30 3.66 3.64

B. Crosslink 0.03 0.15 0.02 0.03 0.00 0.00 0.00

1

DS Free 0.31 0.34 0.09 0.10 0.08 0.09 0.06

X X

Total 0.34 0.49 0.11 0.13 0.08 0.09 0.06

54% succ. acid

acid acid acid acid acid

none none

Catalyst

b

C

succ. succ. succ. succ. succ.

Air-dried

Baratte reaction at 145°C for three hours under nitrogen and aspirator vacuum; remaining Baratte reactions at 160°C for ninety minutes.

57

57

54% 54% 54% 54% 54%

Ν,Ν-diethyl melt Ν,Ν-diethyl melt

Dry sheets Shredded Merc.

Conditions "Never-dried" pulp Washed Alcohol Acetone

a

50 51 52 53 54 55 56

e

d

56

55

t

5 3

52

50?

Reactant

A.

Baratte reactions of wood pulps with Ν, N-diethyl succinamic and succinamic acids

Sample designation Cellunier-F Cellunler-P

Table V.

Hi

ο

S

6.

WADSWORTH AND CUCULO

Wood Pulp-afi-Amic

Acid Reactions

99

Baratte reactions of "never-dried" pulps and " n e v e r - d r i e d " p u l p s which had been s o l v e n t exchanged w i t h a l c o h o l s a l l y i e l d e d r a t h e r l o w DS v a l u e s o f a p p r o x i m a t e l y 0.1 when r e a c t e d w i t h 54 p e r c e n t s u c cinamic acid. The r e a c t i o n s were p e r f o r m e d b o t h w i t h and w i t h o u t : c a t a l y s t , a s p i r a t o r vacuum, and n i t r o g e n atmosphere. T h e l o w e s t DS 0.06, was o b t a i n e d when s t e a m was f o r c e d i n t o the r o t a t i n g f l a s k throughout the r e a c t i o n . H y d r o l y s i s of the succinamic a c i d to t h e l e s s r e a c t i v e monoammonium s u c c i n a t e (1^7) o b v i o u s l y has a g r e a t e r p o s s i b i l i t y i n the B a r a t t e r e a c t i o n s t h a n under pad-bake c o n d i t i o n s where t h e w a t e r i s q u i c k l y removed a f t e r p e r f o r m i n g the b e n e f i c i a l e f f e c t of s w e l l i n g the c e l l u l o s e The r a t h e r h i g r e a c t i o n s were o f l i t t l e consequence low d e g r e e s o f r e a c t i o n o b t a i n e d .

c o n s i d e r i n g the

S o l u b i l i t y Determinations. S a m p l e n u m b e r 28, padb a k e d w i t h 54% s u c c i n a m i c a c i d w i t h c a t a l y s t , and s a m p l e n u m b e r 4 1 , p a d - b a k e d w i t h 6 1 . 9 % ammonium s u c c i n a m a t e w e r e d i s s o l v e d a t a c o n c e n t r a t i o n o f 0.5% cellul o s e h e m i s u c c i n a t e i n 10% s o d i u m h y d r o x i d e a t - 1 0 ° C . B o t h h a d t o t a l DS v a l u e s o f a p p r o x i m a t e l y 0.6. Sample n u m b e r 2 8 a p p e a r e d s o l u b l e a f t e r 30 m i n u t e s , a n d h a d a c l e a r , b u t amber c o l o r . A f t e r approximately one h o u r , s a m p l e 41 y i e l d e d a c l e a r , c o l o r l e s s s o l u t i o n . A f t e r t h r e e hours a t -10°C, the samples were p l a c e d i n t h e l o w e r p a r t o f t h e r e f r i g e r a t o r a t 7.5°C and left overnight. Upon s t a n d i n g , some p a r t i c u l a t e m a t t e r , s m a l l e r t h a n f i b e r s i n s i z e , were n o t i c e d . The solut i o n s were f i l t e r e d t h r o u g h a medium p o r o s i t y g l a s s f r i t , a n d t h e c e l l u l o s e was regenerated with the a d d i t i o n of acetone. T h e s a m p l e was t h e n c e n t r i f u g e d , a n d t h e a c e t o n e a n d a q u e o u s m i x t u r e was d e c a n t e d . At t h i s p o i n t , some f r a c t i o n a t i o n o f t h e c e l l u l o s e was suspected because w i t h both samples, a r i n g o f p r e c i p i t a n t was o b s e r v e d s u s p e n d e d a b o v e t h e s o l i d f r a c t i o n a t t h e bottom of the c e n t r i f u g e tube. These upper phases w e r e s e p a r a t e d a n d w e i g h e d , a n d r e p r e s e n t e d 0.8% of s a m p l e 2 8 a n d 4.1% o f s a m p l e 41 t h a t w e r e o r i g i n a l l y dissolved. The c o a g u l a t e d s a m p l e s w e r e w a s h e d w i t h w a t e r u n t i l n e u t r a l , c e n t r i f u g e d , and p o u r e d into aluminum w e i g h i n g d i s h e s , and upon d r y i n g o v e r n i g h t a t room t e m p e r a t u r e formed f i l m s . The f i l m s were t r a n s l u c e n t , a n d s o m e w h a t b r i t t l e , b u t a p p e a r e d t o be strong. A l t h o u g h d i l i g e n t e f f o r t s w e r e n o t made t o s a v e a l l t h e m a t e r i a l , 55% o f s a m p l e 28 w h i c h was o r i g i n a l l y d i s s o l v e d a n d 57% o f s a m p l e 41 w e r e c o n -

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

100

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

C e l l u l o s e h e m i s u c c i n a t e s w i t h a DS o f 0.4 and h i g h e r h a v e b e e n d i s s o l v e d by A l l e n and C u c u l o (26) a n d i n t h i s w o r k a t a c o n c e n t r a t i o n o f 0.5% derivative i n 10% s o d i u m h y d r o x i d e a t t e m p e r a t u r e o f - 1 0 ° C , 2 ° C , and 7.5°C. S o l u b i l i t i e s at higher concentrations of d e r i v a t i v e w e r e n o t e v a l u a t e d , a l t h o u g h 5% c e l l u l o s e h e m i s u c c i n a t e h a s b e e n d i s s o l v e d b y A l l e n (26) i n 10% s o d i u m h y d r o x i d e a t room t e m p e r a t u r e . The d e r i v a t i v e h o w e v e r , was p r o d u c e d b y r a c t i n g r a y o n , w h i c h h a s a much l o w e r DP a n d i s m o r e a c c e s s i b l e t h a n wood p u l p , with succinamic acid w i t h an a c i d c a t a l y s t . These c o n d i t i o n s h a v e b e e n shown t o r e s u l t i n s e v e r e c h a i n d e g r a d a t i o n i n t h e p r e s e n t work. The e x a c t n a t u r e o f these solutions, i warrant f u r t h e r s t u d i e s a n d p r e c i s e m e t h o d s as l i g h t s c a t t e r i n g . Degree o f P o l y m e r i z a t i o n . The o b j e c t i v e o f t h i s p r e s e n t work i s t o o b t a i n a h i g h degree o f r e a c t i o n w i t h minimum d e g r a d a t i o n i n t h e r e a c t i o n o f α , β - a m i c a c i d s w i t h wood p u l p . W i t h s u f f i c i e n t l y h i g h DS t h e derivatives should dissolve i n dilute alkaline solu­ t i o n s , and p o s s i b l y i n n o n - s a p o n i f y i n g s o l u t i o n s . Improved s o l u b i l i t y a t t h e expense o f c e l l u l o s e c h a i n d e g r a d a t i o n , however, i s not d e s i r e d . I t has been shown (2J_, 23, ,29, 30) t h a t l o w a n d m e d i u m DP c e l l u ­ l o s e o f h i g h a c c e s s i b i l i t y w i l l d i s s o l v e i n 9 t o 10 p e r c e n t sodium h y d r o x i d e a t -5°C. F i g u r e s 4, 5, a n d 6 c l e a r l y show t h a t t h e r e i s o n l y s l i g h t d e g r a d a t i o n o f t h e wood p u l p c o n t r o l s , e v e n when s u b j e c t e d t o t h e same b a k i n g a n d s a p o n i f i c a ­ t i o n t r e a t m e n t s as r e c e i v e d i n t h e r e a c t i o n and subse­ quent analyses. T h e r e d u c t i o n s i n DP u p o n t r e a t m e n t with succinamic a c i d i n the presence of c a t a l y s t are striking. I n c r e a s e s i n DP o f a p p r o x i m a t e l y 100 a n h y d r o g l u c o s e u n i t s (AGU) w e r e n o t e d w i t h a l l t h r e e p u l p s upon t h e r e m o v a l o f t h e c a t a l y s t . I n F i g u r e 5, ammonium s u c c i n a m a t e w i t h c a t a l y s t r e s u l t e d i n a p p r o ­ x i m a t e l y t h e same DP a s s u c c i n a m i c a c i d w i t h o u t c a t a ­ l y s t , a n d as shown i n F i g u r e 6, t h e ammonium s u c c i n a ­ mate w i t h c a t a l y s t r e s u l t e d i n a s l i g h t i n c r e a s e i n DP. F i g u r e 7 i l l u s t r a t e s the e f f e c t s of removing the ammonium s u l f a m a t e c a t a l y s t a n d o f t h e s u b s t i t u t i o n o f ammonium s u c c i n a m a t e o n t h e DP o f t h e s a p o n i f i e d d e r i v a t i v e a n d o n t h e DP o f t h e r e g e n e r a t e d f i l m s . The number a t t h e t o p o f e a c h b a r r e p r e s e n t s t h e t o t a l DS o f t h e o r i g i n a l d e r i v a t i v e . Removal o f t h e c a t a l ­ y s t i n c r e a s e s t h e DP f r o m 180 t o 270. The u s e o f ammonium s u c c i n a m a t e w i t h c a t a l y s t r e s u l t e d i n an i n ­ c r e a s e t o a DP o f 305. A f u r t h e r i n c r e a s e i n DP t o

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

6.

WADSWORTH AND CUCULO

Wood Pulp-afi-Amic

• Cumulative treatment 0 Succ. acid + catalyst

1200

Acid Reactions

IS) Succ. acid, no catalyst

1000 CL

Ο

800 600 400 200 Dry Shredded Merc. Handsheet Baked Sapon. Sheet I80C/15 Control Figure 4.

Effect of treatment conditions

• Cumulative treatment 0 Succ. acid+catalyst

800

on DP of

SaponDerivative

Rayocord-X-F

El Succ. acid, no catalyst S Amm succ.+catalyst

700 600 500 400 300 200 100 Dry Shredded Merc. Handsheet Baked Sapon. Sheet I80C/1Ç Control Figure 5.

Effect of treatment conditions

on DP of

Sapon Derivative Cellunier-F

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

101

102

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

• Cumulative treatment

600 h

• Succ, acid + catalyst

SI Succ. acid, no catalyst •Amm. succ.+catalyst

500

ÛL

Ο

400 300 200 100 Dry Shredded Merc. Handsheet Baked Sapon. Sheet I80*C/15 Control min. Figure

6.

600 500 400

5-

300

Effect of treatment conditions

on DP of

Sapon. Derivative Raysetect-J

0 Succ. acid+catalyst SI Succ. acid, no catalyst S Amm. succ.+catalyst SB Amm. succ, no catalyst 3.6 Ο Succ. acid+catalyst-regen. film • Amm. succ., no catalyst-regen. film 30.6 0.7

0.5

£4

200 100 Saponified Derivative

Regenerated Rim

Figure 7. Effect on DP of Rayselect-J of ammonium sulfamate catalyst and of the substitution of ammonium succinamate for succinamic acid

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

6.

wADswoRTH AND CUCULO

Wood ΡυΙρ-α,β-Amic

Acid Reactions

103 5

401 was o b t a i n e d b y r e m o v i n g t h e c a t a l y s t f r o m ammo nium succinamate, a n d s t i l l a t a DS o f 0.6. The DP v a l u e s o f t h e r e g e n e r a t e d f i l m s r e f l e c t e d t h e same t r e n d e x c e p t t h e y w e r e a l i t t l e h i g h e r due t o t h e f r a c t i o n a t i o n t h a t was n o t e d d u r i n g t h e c o a g u l a t i o n and w a s h i n g s t e p s . H i g h l y s i g n i f i c a n t was t h e f a c t t h a t t h e DP o f t h e r e g e n e r a t e d f i l m p r o d u c e d f r o m t h e r e a c t i o n o f ammonium s u c c i n a m a t e w i t h w o o d p u l p was 49 3, a n d a l m o s t as much as t h a t o f t h e s t a r t i n g w o o d pulp. The DP l o s s o f w o o d c e l l u l o s e a s a f u n c t i o n o f t o t a l DS i n t h e r e a c t i o n o f w o o d p u l p w i t h succinamaic a c i d i s shown i n F i g u r e 8. Although the c o e f f i c i e n t s of d e t e r m i n a t i o n ( r ^ the high degree of v i r t u e o f the f a c t t h a t the d a t a were g a t h e r e d o v e r a t w o - y e a r p e r i o d w i t h f o u r d i f f e r e n t wood p u l p s . The p l o t s show t h a t DP l o s s w i t h s u c c i n a m i c a c i d i s l e s s without c a t a l y s t , but i s s t i l l a p p r e c i a b l e at h i g h e r DS. In F i g u r e 9, DP l o s s w i t h ammonium succinamate w i t h c a t a l y s t i s almost i d e n t i c a l t o t h a t of Ν,Νd i e t h y l succinamic acid without catalyst. Removal o f t h e c a t a l y s t f r o m ammonium s u c c i n a m a t e , results in a l m o s t a c o m p l e t e l e v e l l i n g o f f o f DP l o s s w i t h i n ­ c r e a s i n g DS. A l t h o u g h t h e r e were o n l y t h r e e p o i n t s i n t h e l a t t e r p l o t , t h e v a l u e o f r ^ was q u i t e g o o d . N i t r o g e n and S u l f u r A n a l y s i s . N i t r o g e n and s u l f u r a n a l y s e s w e r e p e r f o r m e d o n t h e s a m p l e s shown i n Table VI. The a b s e n c e o f s i g n i f i c a n t s u l f u r c o n t e n t i n t h e sampes w h i c h h a d b e e n c a t a l y z e d w i t h ammonium s u l f a m a t e c a t a l y s t i n d i c a t e s t h a t the s u l f u r had n o t combined c h e m i c a l l y w i t h the c e l l u l o s e . The slightly h i g h e r n i t r o g e n c o n t e n t o f the samples r e a c t e d w i t h ammonium s u c c i n a m a t e i n d i c a t e d t h a t some h a l f - a m i d e e s t e r (^8) may h a v e b e e n produced. Carboxyl Determinations. A comparison of carboxyl d e t e r m i n a t i o n s by s i l v e r a b s o r p t i o n and by c a l c i u m a c e t a t e methods i s g i v e n i n T a b l e V I I . The determina­ t i o n o f c a r b o x y l c o n t e n t by t h e c a l c i u m a c e t a t e method u s i n g C r a m e r s c o r r e c t i o n f a c t o r (8_, 12) r e q u i r e s an e x a c t one gram o f s a m p l e , w h e r e a s t h e d e t e r m i n a t i o n o f c a r b o x y l g r o u p b y s i l v e r a b s o r p t i o n was p e r f o r m e d on 0.2 t o 0.5 g r a m s . W h e n e v e r s a m p l e s i z e was a limita­ t i o n , c a r b o x y l c o n t e n t was d e t e r m i n e d b y s i l v e r absorp­ tion. S u f f i c i e n t q u a n t i t i e s o f the samples i n T a b l e V I I were produced t o a l l o w f o r a comparison o f the two methods. The s i l v e r a b s o r p t i o n m e t h o d was found t o 1

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

104

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

1

80.0

1

1

1

1

1

1—

1

ι

A Amm. succ.+catalyst

—

— Δ Amm. succ, no catalyst — • Ν,Ν-diethyl succ. acid, no catalyst

r =0.94 2

-

;£r =0.98 2

60.0 40.0

•

r =0.97 2

20.0 »

ι

ι

ι

1

1

0.1

0.2

0.3

0.4

0.5

0.6

— ι —

0.7

0.8

0.9

Total DS Figure 9. DP loss of wood cellulose as a function of total DS with ammonium succinamate with and without catalyst and with Ν,Ν-diethyl succinamic acid

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

Note:

a

analysis

test.

combustion

Schoniger

Flash

technique.

Pad-bake r e a c t i o n s p e r f o r m e d ort R a y s e l e c t - J p u l p ,

: < 0.2 < 0.2

no

Ν,Ν-diethyl m e l t

43

< 0.2 < 0.2 0.38 0.30

no

succ.

61.9% amm.

41

< 0.2 < 0.2 0.44 0.49

X

succ.

61.9% amm.

39

acid

54% s u c c .

27

< 0.2 < 0.2

Sulfur,

data

< 0.2 < 0.2

Catalyst

Experimental _,a Nitrogen, Â

X

Reactant

N i t r o g e n and s u l f u r

Sample no.

Table VI.

%

b

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

by c a l c i u m a c e t a t e method

^Carboxyl c o n t e n t d e t e r m i n e d

(Silver

_ X

(8,12).

s o l u t i o n s (L3 )

0.07 0.04 0.00 0.07 0.04 0.08 0.01 0.00 0.00 0.00 0.00 0.00 0.01^ 0TQ2

abs. - Ca. Ac.) Free DS

from s i l v e r m e t a - n i t r o p h e n o l a t e

0.46 0.41 0.46 0.47 0.43 0.48 0.23 0.08 0.10 0.08 0.09 0.06 0.08

Calcium acetate Free DSb

by a b s o r p t i o n of s i l v e r

0.53 0.45 0.46 0.54 0.47 0.56 0.24 0.08 0.10 0.08 0.09 0.06 0.09

a

S i l v e r absorption Free D S

a b s o r p t i o n and by c a l c i u m a c e t a t e methods

^Carboxyl c o n t e n t determined

22 24 28 30 33 35 37 52 53 54 55 56 57

Sample no.

Comparison o f c a r b o x y l d e t e r m i n a t i o n s by s i l v e r

Table V I I .

6.

wADswoRTH AND CUCULO

Wood ?ulp-afi-Amic

Acid Reactions

107

r e s u l t i n h i g h e r DS v a l u e s - o n t h e a v e r a g e o f 0.02 h i g h e r t h a n t h o s e o f t h e c a l c i u m a c e t a t e m e t h o d , how­ e v e r , t h e d i f f e r e n c e s a p p e a r e d t o be g r e a t e r w i t h t h e h i g h e r degrees of r e a c t i o n . Plans

f o r Future

Work

P l a n s f o r f u t u r e work a r e t o p e r f o r m pad-bake r e a c t i o n s o f aqueous Ν,Ν-diethyl s u c c i n a m i c a c i d and Ν , Ν - d i e t h y l ammonium s u c c i n a m a t e o n m e r c e r i z e d wood pulp. T h e u s e o f l i q u i d a n h y d r o u s ammonia b e c a u s e o f i t s g r e a t s w e l l i n g and p l a s t i c i z i n g e f f e c t s (_31, 32, 33) o n c e l l u l o s e w i l l a l s o b e i n v e s t i g a t e d . The T T q u i d ammonia i t s e l f o r the amic a c i d d e r i v a t i v e s t h e l i q u i d ammonia c o u l d s w e l l t h e c e l l u l o s e , s e r v e as a t r a n s p o r t m e d i a f o r t h e a m i c a c i d , a n d be c o n v e n ­ i e n t l y v o l a t i l i z e d o f f as h e a t i s a p p l i e d i n t h e b a k e step. Summary I n t h e p a d - b a k e r e a c t i o n s , t o t a l DS v a l u e s o f up t o 0.70 w e r e o b t a i n e d i n t h e r e a c t i o n o f s u c c i n a m i c a c i d w i t h m e r c e r i z e d w o o d p u l p a n d up t o 0.58 DS was o b t a i n e d i n t h e t r e a t m e n t o f p u l p w i t h 61.9% aqueous ammonium s u c c i n a m a t e . T h e h i g h e r DS v a l u e s o b t a i n e d w i t h s u c c i n a m i c a c i d r e a c t a n t , h o w e v e r , w e r e due t o i n c r e a s e d c r o s s l i n k i n g ; a n d c o n s e q u e n t l y , t h e same l i m i t i n g f r e e DS o f 0.5 was o b t a i n e d w i t h b o t h s u c ­ c i n a m i c a c i d a n d ammonium s u c c i n a m a t e reactants. The pad-bake and B a r a t t e r e a c t i o n s o f Ν , Ν - d i e t h y l s u c c i n ­ a m i c a c i d w i t h m e r c e r i z e d wood p u l p r e s u l t e d i n f r e e DS v a l u e s o f 0.34 a n d 0.3J. r e s p e c t i v e l y , w i t h n e g l i g ­ i b l e c r o s s l i n k i n g i n both r e a c t i o n s . The B a r a t t e r e a c t i o n s w i t h s u c c i n a m i c a c i d and " n e v e r - d r i e d " wood p u l p s y i e l d e d DS v a l u e s o f o n l y a p p r o x i m a t e l y 0.1. T h i s l o w e x t e n t o f r e a c t i o n was p r o b a b l y due t o h y d r o ­ l y s i s o f s u c c i n a m i c a c i d t o monoammonium s u c c i n a t e , w h i c h was favored under the B a r a t t e c o n d i t i o n s . T h e p r o b l e m o f a c e s s i b i l i t y was apparent i n a l l the r e a c t i o n s . W i t h b o t h s u c c i n a m i c a c i d and i t s ammonium s a l t , DS v a l u e s o b t a i n e d w i t h t h e m e r c e r i z e d p u l p s were on t h e o r d e r o f t w i c e t h o s e o b t a i n e d w i t h the unmercerized pulps. With Ν,Ν-diethyl succinamic a c i d , pre-wetting the substrate p r i o r to padding was f o u n d t o make t h e d i f f e r e n c e b e t w e e n n e g l i g i b l e r e ­ a c t i o n a n d an a v e r a g e DS o f 0.34 o n two mercerized pulps. T h e ammonium s u c c i n a m a t e m e l t s w e r e v e r y v i s c o u s a n d r e s u l t e d i n f r e e DS v a l u e s o f 0.16 and

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

0.19 w i t h d r y a n d w e t s u b s t r a t e , r e s p e c t i v e l y , a s c o m p a r e d t o 0.50 f o r t h e a q u e o u s ammonium s a l t p a d . The u s e o f ammonium s u l f a m a t e c a t a l y s t was f o u n d t o be o f l i t t l e consequence f o r i n c r e a s i n g t h e e x t e n t o f r e a c t i o n , a n d was d e l e t e d f r o m t h e p a d b a t h s w i t h ­ o u t a f f e c t i n g f r e e o r c r o s s l i n k DS; b u t was f o u n d t o be o f m a j o r c o n s e q u e n c e i n i t s e f f e c t o n d e g r a d i n g cellulose during the reaction. Significantly less d e g r a d a t i o n o c c u r r e d w h e n t h e c a t a l y s t was r e m o v e d f r o m t h e s u c c i n a m i c a c i d a n d ammonium s u c c i n a m a t e pad b a t h s ; n e v e r t h e l e s s , upon removal o f t h e c a t a l y s t from both pad baths, s u c c i n a m i c a c i d s t i l l r e s u l t e d i n a p p r e c i a b l e d e g r a d a t i o n o f t h e c e l l u l o s e , whereas, ammonium s u c c i n a m a t tion. Highly significan succinamate w i t h o u t c a t a l y s t and s u c c i n a m i c a c i d w i t h c a t a l y s t b o t h r e s u l t e d i n a t o t a l DS o f 0.6 a n d a f r e e DS o f 0.5. C e l l u l o s e h e m i s u c c i n a t e s p r e p a r e d from s u c c i n a m i c a c i d w i t h c a t a l y s t a n d ammonium s u c c i n a m a t e w i t h o u t c a t a l y s t w e r e d i s s o l v e d a t a c o n c e n t r a t i o n o f 0.5% i n 10% s o d i u m h y d r o x i d e a t - 1 0 ° C . Determinations o f s o l u b i l i t y w e r e made w i t h t h e n a k e d . e y e . F i l m s were f o r m e d f r o m . t h e c e l l u l o s e w h i c h was r e g e n e r a t e d b y t h e a d d i t i o n o f acetone t o t h e s o l u t i o n . Infrared analyses c o n f i r m e d t h a t t h e d e r i v a t i v e h a d been s a p o n i f i e d , as was e x p e c t e d , a n d t h a t t h e f i l m s w e r e p u r e c e l l u l o s e . T h e DP o f t h e f i l m p r o d u c e d f r o m t h e s u c c i n a m i c a c i d p l u s c a t a l y s t r e a c t i o n was 2 4 3 , a n d was c o m p a r a b l e t o t h a t o f t h e c o r r e s p o n d i n g d e r i v a t i v e ; w h e r e a s , t h e DP o f t h e f i l m p r o d u c e d f r o m t h e ammonium s u c c i n a m a t e w i t h n o c a t a l y s t was 4 9 3 , a s c o m p a r e d t o t h e u n r e a c t e d wood p u l p DP o f 5 4 4 . Acknowledgements We w i s h t o e x p r e s s o u r a p p r e c i a t i o n t o I T T Rayonier, I n c . f o r f u n d i n g t h i s r e s e a r c h and p r o v i d ­ i n g t h e wood p u l p s , a n d t e c h n i c a l a s s i s t a n c e ; t o D r . Bowman G. Bowman; t o t h e f a c u l t y o f t h e D e p a r t m e n t o f Wood a n d P a p e r S c i e n c e , N o r t h C a r o l i n a S t a t e U n i v e r s i t y , a n d i n p a r t i c u l a r , t o D r . L a r r y G. G r i f f i n for invaluable assistance. We w i s h a l s o t o t h a n k t h e R e s e a r c h G r o u p o f A m e r i c a n E n k a Company f o r t h e i r t e c h n i c a l a d v i c e and a s s i s t a n c e . Literature Cited 1. 2.

Goldstein, I. S., Science, (1975), 189, 847-852. D a v e y , C. Β., Prof, a n d H e a d , Forestry, N. C. State

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3. 4.

5. 6. 7. 8.

9. 10. 11. 12. 13. 14. 15.

16. 17.

18. 19. 20. 21.

22. 23. 24.

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109

University, Raleigh, North Carolina, Private Communication (1976). Handy, C . T., Ε . I . du Pont de Nemours and Co., W i l m i n g t o n , Delaware, P r i v a t e Communication (1976). C u c u l o , J. Α., P r o f e s s o r , T e x t i l e C h e m i s t r y , N . C . S t a t e U n i v e r s i t y , R a l e i g h , N . C., P r i v a t e Communi­ c a t i o n (1973). P e t e r s , R. Η., Textile C h e m i s t r y , Vol. 1, 176-223, Elsevier P u b l i s h i n g Co., New Y o r k (1963). C u c u l o , J. Α., Textile Res. J., (1971), 41, 321-326. D a g e n h a r t , G. S., U n p u b l i s h e d Work (1976). A l l e n , T . C . and J. A . C u c u l o , " C e l l u l o s e Techno­ logy Research, Albin F., Ed., 5 1 - 7 4 Washington (1975). Bowman, B . G., U n p u b l i s h e d Work (1975). A c t o n , W. P . ITT R a y o n i e r , Inc., New Y o r k , P r i v a t e Communication (1974). H a f f , D. R., ITT R a y o n i e r , Inc., New Y o r k , P r i v a t e Communication (1975) . Cramer, F. V., Ε . I . du Pont de Nemours and Co., P r i v a t e Communication (1972). D a v i d s o n , G. F. and T . P . Nevell, S h i r l e y I n s t . Mem. , (1947), 21, 75-84. J o h n s o n , P . R . , B . G . Bowman and J. A . C u c u l o , Textile R e s . J., (1975), 45, 314-316. Am. S o c . T e s t i n g M a t e r i a l s , P h i l a d e l p h i a , ASTM D e s i g n a t i o n : D 1795-62 (Reapproved 1968), P a r t 21, 169-175. Newman, S . , L . Loeb and C . M. C o n r a d , J. Polym. Sci., (1953), 10, 463-487. Bowman, B . G., P h . D . Dissertation, Department o f Textile Chemistry, North Carolina State University, R a l e i g h , North C a r o l i n a (1975). B e n d e r , M. L., Y. Chow and F. C h l o u p a k , J. Am. Chem. Soc. (1958), 80, 5380-5384. B e n d e r , M. L., J. Am. Chem. Soc., (1960), 79, 1258-1259. B e n d e r , M. L., Chem. R e v . , (1960), 60, 53-113. T r e i b e r , Ε., "Polymer Handbook," B r a n d r u p , J. and Ε . H . Immergut, E d s . V - 9 8 - V - 1 0 0 , John W i l e y & Sons, New York (1975). Genung, L . B . and R. C . Mallatt, I n d . and E n g . Chem., (1941), 13 ( 6 ) , 369-374. J o h n s o n , Ε . H . and J. A . C u c u l o , Textile Res. J., (1973), 43, 283-293. B a t t i s t a , S. C., J. A . Howsmon, F . F. Morehead and W. A . S i s s o n , I n d . and E n g . Chem., (1956), 48 (2) 333-335.

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27. 28. 29. 30. 31. 32. 33.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY Scallan, Α. Μ., Textile Res. J., (1971), 41 647653. Allen, T. C. and J. A. Cuculo, "Proceedings of the Eight Cellulose Conference. III General Papers," Timell, T.E., E d . , 811-829, John Wiley & Sons, New York (1976). Davidson, G. F., J. Textile Inst., (1934), 25, Τ 174-T196. Davidson, G . F . , J. Textile Inst., (1936), 27, T112-T130. Davidson, G. F., J. Textile Inst., (1937), 28, T27-T44. Rossner, U. Dtsch Textiltech (1966) 16 (5) 304-309. Lewin, M. and L Part C, (1971), 36, 213-229. Lewin, M . , R. O. Rau and S. B. Sello, Textile Res. J., (1974), 44, 680-686. Schleicher, H . , C. Daniels and B. Philipp, J . Polym. S c i . , Part C, (1974), 47, 251-260.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

7 Hollow Fibers as Controlled Vapor Release Devices T. W. BROOKS, E. ASHARE, and D. W. SWENSON Conrel, An Albany International Co., 735 Providence Highway, Norwood, MA 02062

In recent years controlled release of active materials has emerged as a distinct end-use needs in medicine, agriculture, forestry and the home. The subject has gained enough prominence to deserve a book (1), two international symposia (2), and a symposium scheduled for this centennial meeting of the A m e r i c a n Chemical Society. A growing number of c o m m e r c i a l products are based on controlled release formulations including such familiar items as time release oral medications, fragrance dispensing wicks and gels, and impregnated plastic pesticide strips or animal collars. Modern controlled release devices and systems such as impregnated plastic or rubber matrices, membrane envelopes, laminated poromerics and microcapsules testify to the growing level of sophistication being demanded of this technology to satisfy increasingly complex end-use requirements. This paper w i l l deal with the use of hollow polymeric synthetic fibers as a controlled release medium for dispensing vaporizable materials. The underlying principles of the h o l low fiber approach to controlled release vapor dispensing w i l l be discussed along with examples of how these principles can be applied to specific controlled release formulation needs and some results f r o m actual field testing of hollow fiber dispensers for insect pheromones. In keeping with the spirit and i n tent of the symposium this paper provides an example of how man-made fiber technology is being wedded with other seemingly unreleated technologies to obtain products which hold promise in helping us manage our environment more responsibly.

Ill

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

Objectives of Controlled Release Some of the more important objectives in developing con­ trolled release product forms are (1) an extended period of activity for the released material, (2) longer use life for n o r ­ mally nonpersistent (unstable) active materials, (3) more ef­ ficient utilization of active materials, e . g . , lower total dos­ ages, (4) reduced environmental contamination, and (5) greater safety for the users of hazardous materials. C o n ­ trolled release product forms meeting these objectives are becoming especially important in the pesticide field (2) where ecological considerations are dictating the abandonment of per­ sistent materials, lik of less stable materials such as the οrganophosphate and c a r ­ bamate insecticides. Other potential benefits of controlled release product forms include improved specificity of action on target organisms and enhanced economics of application. Thus, whatever the field of application, be it economic ento­ mology, preventive and therapeutic medicine, or consumer products, the broad objective of controlled release is to i m ­ prove the technical performance of an active material in an economical way. Controlled Vapor Release F r o m Hollow Fibers Hollow fibers have been found to be a useful means of con­ fining and mediating the controlled release of a variety of v a porizable materials. If a material is allowed to evaporate from the lumen of a hollow fiber sealed at one end and open at the other, the release curve, obtained by plotting mass r e ­ leased versus time, is characterized by an initial steep slope followed by an extended lower slope flat portion which approx­ imates zero order release kinetics. This release behavior follows form with a l l vaporizable materials as long as they are single component or comprised of mixtures of components with comparable volatilities. T y p i c a l release curves are shown in Figure 1 for two insect pheromones and the insec­ ticide D D V P (2, 2-dichlorovinyl-O, O-dimethyl phosphate). The absolute rate of release for any given material is directly pro­ portional to fiber internal diameter. At a given temperature release rates can be manipulated by adjustments in fiber i n ­ ternal diameter and the number of fibers employed. The active life for dispensing is a function of hollow fiber length, i . e. , the length of the column of active material.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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BROOKS ET AL.

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Controlled Vapor Release Devices

For design purposes only the flat portion of the release curve is used. The initial high rate or "burst effect" portion of the curve can usually be ignored since it represents only a s m a l l percentage of the total lumen charge and a relatively short period of the total dispensing life. The "burst effect" portion of the release curve for an active material can some­ times be eliminated by diluting the lumen charge with a high volatility inert. This ploy is frequently useful in dispenser designs where one wishes to dispense vapor mixtures having individual components with substantially different volatilities. Dilution can also be used to make short lived dispensers which otherwise would have to be made up in inconveniently short lengths. Thus, for a give trolled release dispensers can be formulated knowing only the release curve obtained with a particular fiber material and size at some specified temperature. Designing the dispenser to a specific release rate and lifetime is a simple matter of calculating the number of fiber ends needed to give the desired dose rate and the fiber length needed to achieve a prescribed life span. The need to know the fiber material and internal diameter used in obtaining release curves deserves some explanation. It turns out that evaporation rates for many materials are sensitive to the diameter of the fiber lumen or capillary r e s e r ­ v o i r . That i s , the vapor flux is not directly proportional to the square of the capillary radius for a l l liquid and fiber m a ­ t e r i a l combinations, as one might naively expect. In Table I are shown data which illustrate this phenomenon. Steady state release rates were measured on four different materials using 200 and 500 m i c r o n I. D. hollow fibers. Neutroleumalpha is a commercial general purpose deodorizer formulation, while 4-methyl-3 -heptanol (_1), multistriatin (2), and acubebene (3) are compounds which comprise the three-com-

Φ

4-methyl-3-heptanol

(2) multistriatin

a-cubebene

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

0

10

20

30

40

50

60

70

80

90

DAYS

Figure 1.

Release of various

materials

Table I Comparison of Fluxes for Selected Materials from Two Different Hollow Tiber Sizes*' 1

Material

Flux, em/day^ 500μ 1.1). 200μ I.D.

Neutroleum-alpha

1.8x10

eubeb oil**

5.8x10

multistriatin

2.1x10

4-methyl-3-heptanol

2.2x15

-2 -3 -2 -2

1.8x10

-2

-2 1.5x10 -2 3.4x10 -2 3.16x10

Flux Ratio 200μ:50Ομ

Absolute Release lia to μ^/day/cnd 500μ 200μ

1

5.9

37.4

2.G

1.9

30.5

1.6

6.8

69.6

1.4

7.2

64.1

Fiber material is undrawn polyester (polyethylene terephthalatc). All release measurements were made at 21 ± 1°C and 65 ± 5", relative humidity. 3

The 200μ and 500μ fiber I.D.'s correspond to lumen cross-sectional areas of 3.24x10~ and 2.03x10~ cm respectively. This corresponds to a ratio of the larger to the smaller cross-sectional area of 6.3. 4

3

2

Ά proprietary general purpose deodorizer formulation comprised of a blend of essential oils and aromatic chemicals. Marketed by Fritzsche Bros., Inc., New York. α-cubebene is a constituent which is extracted from the berry of the Java pepper plant.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

I

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Controlled Vapor Release Devices

ponent a g g r e g a t i o n p h e r o m o n e of the s m a l l e r E u r o p e a n

elm

b a r k beetle, S c o l y t u s m u l t i s t r i a t u s ( M a r s h a m ) (4). C o m p a r i s o n of f l u x e s of t h e s e m a t e r i a l s f r o m the two

different sized fiber

l u m i n a r e v e a l s that r e l e a s e r a t e v a r i e s u n p r e d i c t a b l y capillary diameter.

m a i n e q u a l f o r the two

diameters.

r i a l s f l u x r a t i o s f o r 200 to 2.6.

with

O n l y w i t h neutr o l e u m - a l p h a did f l u x r e ­ and

W i t h the t h r e e other

mate­

500p d i a m e t e r s r a n g e d f r o m

1.4

T h u s i n going f r o m the s m a l l e r to the l a r g e r d i a m e t e r ,

r e l e a s e r a t e i n c r e a s e d by m o r e than the r a t i o of c r o s s sectional An

areas. e x p l a n a t i o n f o r this p h e n o m e n o n p r o b a b l y l i e s i n the

s u r f a c e e n e r g y r e l a t i o n s h i p s between the l i q u i d c h a r g e and fiber wall.

the

It i s know

the v a p o r p r e s s u r e abov r a d i u s of c u r v a t u r e

of that s u r f a c e .

F o r different liquid-fiber

m a t e r i a l c o m b i n a t i o n s the l i q u i d m e n i s c u s - f i b e r

wall

contact

angles w i l l be d i f f e r e n t , and t h e r e f o r e the r a d i i of c u r v a t u r e the m e n i s c i w i l l a l s o d i f f e r .

It i s i m p o r t a n t to r e c o g n i z e

e x i s t e n c e of this p h e n o m e n o n w h e n c o n s i d e r i n g the d e s i g n hollow fiber c o n t r o l l e d r e l e a s e f o r m u l a t i o n s . subtle c o m p l i c a t i o n

of

the of

In p r a c t i c e this

i s a v o i d e d by m e a s u r i n g r e l e a s e c u r v e s

w i t h the f i b e r m a t e r i a l and

fiber internal diameter which w i l l

be u s e d f o r a s p e c i f i c f o r m u l a t i o n .

T h i s is e s p e c i a l l y i m p o r ­

tant w i t h i n s e c t p h e r o m o n e s w h e r e b i o l o g i c a l d o s e - r e s p o n s e r e l a t i o n s h i p s often d i c t a t e a v e r y p r e c i s e and

constant r e l e a s e

r a t e i n o r d e r to m a k e i n s e c t m o n i t o r i n g t r a p s f u n c t i o n M e c h a n i s m of V a p o r R e l e a s e f r o m H o l l o w The

properly

Fiber

m e c h a n i s m of v a p o r r e l e a s e f r o m hollow f i b e r s , i f

t r a n s - w a l l permeation is excluded, is a simple

three-step

process. 1.

E v a p o r a t i o n at the l i q u i d - v a p o r i n t e r f a c e .

2.

D i f f u s i o n f r o m the l i q u i d - v a p o r i n t e r f a c e to the

3.

C o n v e c t i o n away f r o m the open

open end of the h o l l o w f i b e r . end.

A d e t a i l e d d i s c u s s i o n of the m a s s t r a n s p o r t t h e o r y i n v o l v e d i n this p r o c e s s is g i v e n e l s e w h e r e (3^,_5). t i o n d e r i v e d f r o m the t h e o r y i s

v a

p

The

r e l e a s e r a t e equa­

γ/2

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

w h e r e d l / d t , the change i n m e n i s c u s l e v e l w i t h t i m e , i s d i ­ r e c t l y p r o p o r t i o n a l to the d i s p e n s i n g r a t e , M i s the m o l e c u l a r weight of the d i s p e n s e d m a t e r i a l , c i s its m o l a r density, D i s the d i f f u s i o n c o e f f i c i e n t ^ / i s the l i q u i d density, P ^ the v a p o r p r e s s u r e of the v o l a t i l e m a t e r i a l , and Ρ i s the p r e v a i l ­ ing a t m o s p h e r i c p r e s s u r e . T h e v a l i d i t y of the equation w a s e x a m i n e d u s i n g c a r b o n t e t r a c h l o r i d e as a m o d e l m a t e r i a l . F i g u r e 2 shows a l o g a r i t h m i c plot o f e v a p o r a t i o n r a t e v e r s u s t i m e i n w h i c h c a l c u l a t e d and e x p e r i m e n t a l l y o b s e r v e d c u r v e s a r e d i s p l a y e d . T h e a g r e e m e n t between e x p e r i m e n t and t h e o r y t e s t i f i e s quite w e l l f o r the v a l i d i t y of the r a t e e x p r e s s i o n . 7

V a

I

S

a

R e l e a s e of m a t e r i a l by p e r m e a t i o n t h r o u g h the f i b e r w a l l is e x c l u d e d f r o m c o n s i d e r a t i o r e t i c a l r e a s o n s . In p r a c t i c e f i b e r m a t e r i a l s a r e s e l e c t e d w h i c h a r e i m p e r m e a b l e to the a c t i v e m a t e r i a l to be d i s p e n s e d . T h i s i s n e c e s s a r y s i n c e the f i b e r m u s t confine the a c t i v e m a ­ t e r i a l d u r i n g s t o r a g e p r i o r to a c t i v a t i n g r e l e a s e by opening the f i b e r end. Hollow F i b e r Controlled Release Product F o r m s C o n t r o l l e d r e l e a s e v a p o r d i s p e n s e r s have been f a s h i o n e d b a s i c a l l y i n two f o r m s . In the f i r s t a p a r a l l e l a r r a y of f i b e r s is f i x e d to an a d h e s i v e tape. A f t e r p r e s s u r e f i l l i n g the a c t i v e m a t e r i a l into the f i b e r s , the f i b e r s a r e s e a l e d u l t r a s o n i c a l l y at r e g u l a r i n t e r v a l s along the tape. T h e a c t i v e m a t e r i a l m u s t be i n l i q u i d f o r m f o r the f i l l i n g o p e r a t i o n . R e l e a s e i s a c t i v a t e d by cutting the tape at a point adjacent to the s e a l s t h e r e b y op­ ening f i b e r ends. A g r a p h i c a l i l l u s t r a t i o n of this d i s p e n s e r f o r m i s shown i n F i g u r e 3. T h i s k i n d of d i s p e n s e r is u s e f u l for the exact p o s i t i o n i n g of v a p o r point s o u r c e s . Example u s e s m i g h t i n c l u d e the b a i t i n g of i n s e c t t r a p s w i t h a n a t t r a c tant, d i s p e n s i n g a v a p o r a c t i o n i n s e c t i c i d e to p a c k a g e s o r c o n t a i n e r s of s t o r e d goods s u s c e p t i b l e to i n s e c t attack, and deodorizing enclosed areas with air freshening fragrances or masking chemicals. A s e c o n d f o r m of d i s p e n s e r i s m a d e by s e a l i n g i n d i v i d ­ u a l f i b e r s at r e g u l a r i n t e r v a l s a n d t h e n c h o p p i n g at a p r e ­ d e t e r m i n e d d i s t a n c e f r o m the s e a l . T h i s c h o p p e d f i b e r f o r m is d e s i g n e d p r i m a r i l y f o r b r o a d c a s t i n g v a p o r point s o u r c e s over large areas. C h a r g i n g chopped f i b e r s with an active m a t e r i a l i s a c c o m p l i s h e d by i m m e r s i n g the f i b e r s i n the m a t e r i a l , d r a w i n g a v a c u u m to r e m o v e a i r a n d other g a s e s f r o m the l u m e n , a n d then r e l e a s i n g the v a c u u m . A g a i n , the

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

7.

BROOKS ET AL. -4 I0

4

117

Controlled Vapor Release Devices

r

THEORETICAL Ο

EXPERIMENTAL

Figure

2.

Rate of release of

TIME (hrs.)

tetrachloride

Continuous Tape

Single Dispenser Figure 3.

Tape form hollow fiber vapor

dispenser

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

carbon

118

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

active material must be in a liquid f o r m at the time of filling. Chopped fibers charged with active material are stored in hermetically sealed containers. Release is activated when the container is opened. Example uses for the chopped fiber form of hollow fiber dispenser would include broadcast dissemination of insect sex attractant pheromones for mating disruption of agricultural or forest insect pests (pheromones and pheromone dispensing applications are discussed further below), insecticide dispensing, and possibly soil fumigation. In both product forms, release rates are governed by fiber size and the number of fiber ends while active life is governed by fiber length. Which product form is preferred for a given applicatio and the economics of the application. The Application of Hollow Fiber Vapor Dispensing to Insect Pheromones Insect pheromones are volatile organic compounds produced by insects for purposes of communication through their highly developed olfactory sensory systems (6). These highly specific chemical messengers serve to influence insect behavior in a variety of ways. Pheromones may function to signal alarm, mating conduct, t r a i l marks, oviposit, aggregation and specialized behavior in the regulation of social i n sect colonies. Sex attractant insect pheromones have been of particular interest to entomologists since they raise the possibility of controlling pest insects by interdicting the sexual communication which leads to mating and proliferation of populations f7, 8_). If population suppression could be accomplished with pheromones, of course, many of the environmental hazards associated with chemical insecticide control measures might be avoided. Indeed environmental considerations have been a motivating influence behind much of the research on i n sect pheromones. Three basic strategies are being developed for the use of pheromones in insect pest management. These are (1) m o n i toring and survey trapping, (2) mass trapping and (3) mating disruption (8). In the first case pheromone baited traps are employed to assist in the detection and location of infestations, timing of insecticide applications, and monitoring of the effectiveness of control measures. The mass trapping stratagem is designed to achieve pest population suppression by physically removing insects f r o m the environment, a novel refine-

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

7.

BROOKS E T A L .

Controlled Vapor Release Devices

119

ment of the flypaper approach. In the mating disruption approach an area is permeated with sex pheromone in order to interfere with the insect's olfactory inter-sexual communication system. By thus subverting the mating and reproduction process it is hoped that population suppression can be achieved without resort to lethal agents. The application of these pheromone use strategies is made a challenging task by two important factors. First, pheromones are frequently very expensive chemicals to synthesize. Those which are commercially available may cost anywhere from several hundred to several thousand dollars per pound. Second, pheromones typically possess a high order of biological activity an ute quantities as compared, say, to conventional chemical i n secticides. Application rates for mating disruption of lepidopterous species, for example, are on the order of grams per acre-season. For successful pheromone trapping the lure frequently must be metered out at a very precise rate. It is not uncommon for the optimum dose rate of a pheromone trap bait to be on the order of micrograms per day. An underdose can cause the trap to fail for lack of attractiveness while an overdose can lead to disorientation of an insect attracted to the vicinity of the trap so that he fails to find his way i n . These factors necessitate a controlled release method of pheromone dispensing which is precise, reliable, and efficient. In many instances the development of pheromone technology for insect control and the development of controlled release technology have gone hand in hand. Without an adequate controlled r e lease system it is doubtful that pheromones could ever be made sufficiently practical and economical for pest control use on a commercial scale. Our investigations into insect pheromone dispensing with hollow fibers have involved work with more than twenty different insects. Out of this number three have been selected as illustrative examples of how the principles of hollow fiber vapor dispensing can be applied in various ways to the controlled release of pheromones. Hollow fiber pheromone dispensers have been prepared and field tested for the trapping of the smaller European elm bark beetle, Scolytus multistriatus (Marsham), principle vector for the Dutch elm disease pathogen Ceratocystis ulni. The aggregation pheromone of the elm bark beetle is a mixture comprised of at least three compounds, 4-methyl-3-heptanol (_1), 2, 4-dimethyl-5-ethyl-6, 8-dioxabicyclo (3. 2. 1 ) ocatane(2),

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

and a-cubebene (a constituent of cubeb oil) (3). Compound (2) has been given the t r i v i a l name, multistriatin. The alcohol and multistriatin are beetle-produced while the a-cubebene is a host-produced synergist (4). Release curves for the elm bark beetle pheromone constituents are shown in Figure 4. Note that release rates at steady state are nearly equal for the alcohol and multistriatin while the steady state release rate for cubeb o i l , a much less volatile material, is significantly lower. At the time these experiments were conducted, the optimum release ratio for trapping baits was thought to be: Cubeb o i l 200pg/day multistriati 4-methyl-3-heptanol 40jig/day F r o m these specifications and the respective release curves dispensers were prepared with the following design features: Cubeb o i l 115 fiber ends multistriatin 5 fiber ends 4-methyl-3-heptanol 5 fiber ends A i l fibers were 3 c m in length which corresponds to a design life of 3 months using an overdesign factor of fifty percent. Overdesign of dispenser life is frequently practiced to guard against premature exhaustion in the field owing to unanticipated periods of exceptionally w a r m weather. Dispensers with the above design were field tested in traps set out in Australia in early 1975 when U . S . beetle populations were dormant. The results of these trapping experiments are presented in Table II. The hollow fiber dispensers consistently out-captured beetles when compared to a polyethylene v i a l type of dispenser which is frequently employed by experimenters. Further, as the season progressed the hollow fiber dispensers improved in performance relative to the plastic v i a l s . Since no data were collected after the fifth week, no comment can be made on total performance. The data do suggest however, that the hollow fiber dispensers adhered more closely to release design specifications than did the plastic v i a l s . T h i s , in turn, demonstrates the greater potential hollow fibers offer in designing dispensers for multicomponent pheromones. Most other controlled release devices lack the design flexibility afforded by the hollow fiber approach. Experiments with elm bark beetle pheromone dispensers are continuing in the U . S . where it is hoped that spread of Dutch E l m disease can eventually be arrested by mass trapping of the beetle vector. The results of this work, including eval-

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

BROOKS ET AL.

Controlled Vapor Release Devices CUBEB OIL MULTISTRIATIN 4- METHYL- 3- HEPTANOL

I Ο

L

I

I

I

1

1

4

8

12

16

20

24

1

28

TIME(DAYS)

Figure 4.

Release rate of elm bark beetle pheromone

components

Flm lliii'k Heotlc Trapping Results wit!) Hollow Fiber Pheromone Dispensers Trnp No. 1 3" 4 5 7 8 9 11 12 13 14 1G 17 19 2i 22 23* a

n

a

Trap Installed On Tree Species Eucalyptus saligna Archontophoenix cunningham inna Ditto Nothofagus solandori Ulmus procera Ditto Prumus spp. Ulmus procera Quercus spp. Eucalyptus calopliylla Ulmus uroccra Çcdrus doodara Ulmus procera Pinus radiata Pinus ponderosa Ulmus procera Ditto Total Catches

Dispenser Type" PV

I IF PV IIF PV IIF

—

PV III' PV IIF PV

— —

HF

1 of Total with I IF Dispensers

Meet Jo C'iitch on Dittos (197 2/6 2/2(1 31 0

175

13

54

I)

0

0

15 .6 3 17 ϋ IB 0 4 1G 23 210 33 0 54 0

37 15 35 99 0 144 0 5 302 75 78(i 70 0 235 J)

43(1

1978

15 5 53 35 0 8 0 1 130 4 209 1G 0 31 0 497

143 7 112 193 0 220 0 9 200 7 990 32 0 lfiO 0 2127

73

78

90

8G

"Control trees, traps installed without baits ^PV = polyethylene vials IIF - hollow fiber dispenser

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

uations of controlled release formulations w i l l be reported byother investigators (9). A second insect pheromone chemical to which hollow fiber dispensing has been applied is gossyplure, the sex attractant of the pink bollworm, Pectinophora gossypiella (Saunders). The pink bollworm is a major cotton pest in the U . S. Desert Southwest and in a number of Latin A m e r i c a n countries where cotton is grown. The use of pheromone baited traps to monitor for this insect is becoming a common practice in cotton pest management programs. Gossyplure is a 1:1 mixture of ( Z , Z ) - a n d ( Z , E ) - 7 , 11hexadecadienyl acetates (10). Its attracting power for male moths is remarkable. pink bollworm males to a standard commercial trap is in the range of 2.4 to 4. 0 jig/day. Gossyplure is one pheromone which must be metered out carefully when used as a trap lure for monitoring purposes. This point is illustrated in Figure 5. The dose-response data were taken by field bioassay in a cotton field near Buckeye, A r i z o n a , late in the 1974 growing season. Captured insects were a l l from the local wild population. The plot of number of moths captured versus number of fibers per trap bait shows an optimum dose rate of about 3.2 jig/day, i . e. , eight fibers of 8 m i l I. D . (200p) (see Figure 1). As the number of fibers is increased beyond the optimum, trap catches drop off and tend to become erratic. This response pattern makes it imperative that traps be baited with a pheromone dispenser that gives off a well-defined and constant dose of the attractant. This is crucially important if the trapping results are used for monitoring control programs. The gossyplure experiment illustrates another useful feature of hollow fiber controlled release devices. When a new pheromone is isolated the entomologist often cannot specify an optimum release rate for trap baiting since he lacks doseresponse data of the kind in Figure 5. Hollow fiber dispensers make it convenient to obtain such data by field or laboratory experimentation in which release rates are manipulated simply by varying the number of fiber ends. This technique for obtaining dose-response data with pheromones promises to make the whole process of developing such information a much easier task. A third example of a promising use for hollow fiber pheromone dispensers can be drawn from a recent experiment on disruption of the grape berry moth Paralobesia viteana (Clemons). This insect is a very serious vineyard pest in many

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

7.

BROOKS ET AL.

Controlled

Vapor

Release

Devices

123

of the Eastern U . S . grape growing areas. The sex pheromone of the grape berry moth is (Z)-9-dodeceny1 acetate (11). Multifiber dispensers of the pheromone were placed in a New York vineyard test plot, one per vine and 604 dispensers per acre. Individual dispensers each had nine fiber ends giving a total of 5445 fiber ends per acre. The design release rate was 3. 5x10-7 cm.3 per day giving each point source an output of about 3.2x10-6 m? per day. F o r 605 point sources and a 150-day season the nominal rate of application was 0. 286g per acre-season. The true rate of application was 1. 85 g per acre-season because it was necessary to make the fibers one cm in length. This length was arbitrarily chosen to make it convenient to handle dispenser grape berry moth disruption experiment are summarized in Table III. Note that orientation on pheromone baited traps was disrupted for a period of two and one-half months, after which the experiment was terminated. Disruption of E . argutanus was also observed for the same period of time. The latter i n sect is a local species of no economic consequence. The r e c ord of its disruption serves only as additional evidence that the technique is working. The grape berry moths in this test were lab-reared insects while E . argutanus were f r o m the local wild population. This is the first time, to our knowledge, that orientation disruption of a pest insect was achieved for a two and one-half month periodwith a single pheromone treatment. This fact, coupled with the very modest rate of application, clearly i n dicates that pheromone treatment with a reliable and economical controlled release system has c o m m e r c i a l potential in a g r i culture. Tests planned for the 1976 season w i l l be designed to ascertain whether disruption of the grape berry moth also protects the crop against insect-caused damage. Successful crop protection is the ultimate measure of economic value for any treatment method. A more complete disclosure of the 1975 grape berry moth disruption experiments w i l l be made in a separate publication by Taschenberg and Roe lofs .(12). These investigators conducted the disruption experiment and graciously provided us with the data in Table III, along with other background information. C

Conclusion The principles of controlled vapor release with hollow fibers have been demonstrated in a variety of ways. The con-

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

124

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

60H

III

10 NO.

Figure

5.

Dose-response

40

20

30

OF FIBERS

PER DISPENSER

data for pheromone

trapping

of pink

5C

bollworm

moths

bioassay)

Tabic III Grape Merry Moth Orientation Disruption Tests with Hollow Fiber Phoronione Dispensers - 11)7Γι' Number of Males Captured in 6 Traps

Date

Totals

G RM

Treated Plot 1Î. Argutanus

b

Untr ont (id Cheek Plot I.. Argutanus GUM

Jul

15 20 25 30

0 0 0 0

0 0 0 0

2 1!) 14 7

2 45 65 39

Aug

6 16 26

2 0 0

2 0 1

28 9 11

199 4!) 26

Sept

5 15 25

0 0 0

0 0 0

15 7 11

2

3

123

8 0 0 433

These data were gathered by D r . E . F . Tnschcnborg, Vineyard Laboratory New York State Agricultural Experiment Station, Fredonia, New Y o r k . ^E. argutanus is a non-pest insect attracted by (Z) 9-dodeconyl acetate.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

(field

7. BROOKS ET AL.

Controlled Vapor Release Devices

125

cept has been shown to have potential in specific applications involving the use of insect pheromone for pest management purposes. Based on the test results disclosed in this paper, it is reasonable to expect that hollow fiber vapor dispensing will find a number of commercial applications, some of which will represent a substantial contribution to a safer and better envi­ ronment. Acknowledgements The technical assistance of JoanEllen Hoar and Roger Kitterman in preparing formulations and obtaining field test data is gratefully acknowledged the invaluable contribution g Roelofs of the New York State Agricultural Experiment Station who conducted the grape berry moth experiment, and J. W. Peacock and R. A. Cuthbert of the U. S. Department of Agri­ culture Northeast Forest Experiment Station who arranged for the elm bark beetle tests. Literature Cited (1) Tanquary, A. C., and Lacey, R. Ε., (eds.), "Con­ trolled Release of Biologically Active Agents," Plenum Press, New York (1974c). (2) Cardarelli, N . F . (ed.), "Proceedings of the 1974 Controlled Release Pesticide Symposium," University of Akron, Akron, Ohio, September 16-18, 1974; Harris, F. W., (ed.), "Proceedings of the 1975 Controlled Release Pesticide Symposium, "Wright State University, Dayton, Ohio, Septem­ ber 8-10, 1975. (3) Ashare, Ε., Brooks, T . W . , and Swenson, D.W., "Controlled Release from Hollow Fibers," Ibid., p. 42. (4) Pearce, G. Τ . , Gore, W. E., Silverstein, R . M . , Peacock, J. W., Cuthbert, R. A . , Lanier, G . N . , and Simeone, J. B., J. Chem Ecol., 1, 115 (1975). (5) Ashare, Ε . , Brooks, T . W . , and Swenson, D. W., Paper presented at the American Chemical Society Centennial Meeting, Joint Symposium on "Controlled Release Polymeric Formulations," sponsored by Divisions of Polymer Chemistry and Organic Coatings and Plastics Chemistry, New York, April 19, 1976. (6) Birch, M . C . , E d . , Pheromones, Elsevier Pub. Co., New York (1974c).

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

(7) Jacobson, Μ . , Insect Sex Pheromones, Academic Press, New York (1972c). (8) Roelofs, W., "Manipulating Sex Pheromones for Insect Suppression" in Insecticides of the Future, Jacobsen, M . , E d . , Marcel Dekker, Inc., New York (1975c) p. 41. (9) Peacock, J.W. and Cuthbert, R . A . , private com­ munications. (10) Hummel, Η. E., Gaston, L. Κ., Shorey, H . H . , Kaae, R.S., Byrne, K . J . and Silverstein, R. Μ., Science, 181 873 (1973). (11) Roelofs, W . L . , Tette, J. T., Taschenberg, E. F. and Comeau, Α . , J. Insect Physiol. 17 2235 (1971) (12) Taschenberg munications.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

8 Evolution of Man-Made Fibers Κ Ε. MAGAT and R. E. MORRISON Pioneering Research Laboratory, Textile Fibers Department, Ε. I. du Pont de Nemours & Co., Inc., Wilmington, DE 19898

Let us take a shor tri through wha b called the golden ag of man-made fibers deals only with fibers prepared from organic intermediates and does not include fibers spun from cellulosic derivatives. It all started with the discovery and commercialization of nylon in 1940 and reached the point today where noncellulosic man­ -made fibers account for more than half of the total fiber consumption and are expected to reach about two­ -thirds by 1980 in the United States. The scenario can be divided into four phases: Phase 1 - 1940-1950 - Development of nylon and i n ­ tensive exploration for new fiber-forming polymers. Phase 2 - 1950-1956 - Introduction and commerciali­ zation of major man-made fibers beyond nylon. Phase 3 - 1956- Development of second generation fibers. Phase 4 - 1960- Development of specialty fibers. Research on the last two phases is today.

still

going strong

Phase I With the discovery of nylon and its commercial introduction, fiber research all over the world shifted to a search for other synthetic polymers capable of forming fibers. I n i t i a l l y , the objectives 127

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

128

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

were twofold. (1) To duplicate the properties and feel of natural fibers, the resilience of wool, the luxury of s i l k and the versatility of cotton. (2) To develop a relationship between fiber structure and chemical composition with fiber properties. Literally hundreds of polymers were prepared during this period and spun by the new melt spinning process specifically developed for nylon and by wet or dry spinning used for cellulosic derivatives. The f i r s t targe hosiery market leadin hosiery. Following the overwhelming acceptance of nylon hosiery a second "natural" end-use was tricot capitalizing on its excellent k n i t t a b i l i t y and durab i l i t y resulting in penetration of a major rayon and acetate stronghold. Another major penetration was in tire cord based on nylon's high strength, impact resistance and a b i l i t y to withstand repeated flexing and stresses. A variety of other polyamides were examined and except for 6 nylon which was developed in Germany, 6-6 nylon emerged as the major polyamide candidate from this era. Research turned in the direction of polyesters and vinyl polymers. Two major fibers emerged from this intensive search, poly(ethylene terephthalate) and polyacrylonitrile. Building on Carothers' work the discovery of poly(ethylene terephthalate) fibers by Whinfield and Dixon in England opened the door to a new fiber which could u t i l i z e much of the melt spinning technology developed for nylon. The polyacrylonitrile breakthrough came with the discovery of a solvent which could dissolve this heretofore intractable polymer and thus yield spinnable polymer dopes. With the preparation of hundreds of polyamides, polyesters and polyacrylics, a sound basis for correlating structure and fiber properties was established, opening the door to Phase II.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

8. MAGAT AND MORRISON

Evolution

of Man-Made

129

Fibers

Phase I I As

we

fibers nylon

approached

was p r o c e e d i n g plants

were a l r e a d y

nitrile

fibers

tinuous

filament

first

yarn

The existing

objective

continued

markets.

The v e r s a t i l i t y

leading

or rayon

Polyacrylics

showe

and found blankets.

for

wool-like

and

polypeptides

to fibers

acceptance

I t i s indeed fibers

characteristics opened

became

t h e door

the fourth

The

into

which

of

soon

simulated

i n sweaters, that

centered

on

wool,

carpets the

search

polyamides

met b y

none

the discoveries

poly-

of the chemical

to isotactic

o f Z i e g l e r and

polypropylene

polyolefin fiber

major

research

those

striking

of polyester

out t o be b e s t

which

candidate

and

fiber. and e v a l u a t i o n

l e d to fabrics with

exceeding

went

o f wool.

as t h e major

Intensive fibers

plant

remarkable

initially

turned

t h e mid-50's

emerged

as con-

i n 1952.

t o be t h e p e n e t r a t i o n

and p o l y a c r y l i c s which have

In

started

y

rapid

and

most

polyester

Three

Polyacrylo-

i n 1953.

dependin

Natta

as Orion®

Dacron®

cotton

esters

o f man-made pace.

i n 1950 a n d s t a p l e

became a p p a r e n t

wool

rapid

i n operation.

introduced

commercial

operation

1950, t h e g r o w t h a t a very

unique

o f these

four

characteristics far

o f f a b r i c s from n a t u r a l

fibers.

The

o f these a r e :

(1)

wash-wear

(2)

resistance

to wrinkling

and r e c o v e r y

from

wrinkling (3)

durability

(4)

heat

settability.

These

unusual

areas

and p r o v i d e d

of

the four The

wet be

major

first

standing

properties

entirely

washing

properties

For the f i r s t

wrinkling.

could

end-use growth

fibers.

time

Wrinkles

be removed

from

of polyester

simply

the out-

fibers,

some g a r m e n t s

worn a l l day i n d r y and wet weather

excessive

new

f o r further

two c h a r a c t e r i s t i c s s t e m

recovery

and d r y .

opened

the springboard

without

introduced

both

could

during

by tumbling the

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

130

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

garments

in a dryer.

achieved

not

of

only

polyesters with

ester

with

fabric

polyester alone

c o t t o n and

w h i c h made t h e

be

with

Blending the

blends

of

poly-

degree

of

permanent-press

possible.

Durability of

of nylon

magnitude t o

Boys'

jeans

out.

The

could and

Heat

polyesters provided

be

outworn r a t h e r than

of nylon

unmatched by

a

carpets

any

is

new

apparel. worn

indeed

fiber.

settabilit

attribute.

Heat

and

imparts

fabrics

formation. boarding

settin a memory o f

It started

of hosiery

with

their

the

leading to

t o permanent p l e a t s and the

and

longevity of wearing

finally

durability

remarkable

of

wool.

but

resin-treated cotton provided

strengthening

concept order

These p r o p e r t i e s c o u l d

with

original

discovery of

con-

pre-

seamless hose,

creases

and

enormous t e x t u r e d c o n t i n u o u s

now

spread

i s the

filament

basis

yarn

market. Phase

III Having

polyester, research entered coined

shifted into

by

physical

and

the

fibers

properties, nological

as

with the

tailor-made

parent

the

fiber

1956

and second

characteristics. same b a s i c but

to develop on

materials

offering

novel

These

tech-

markets

and

f o r man-made

superimposed

we as

chemical

to prepare

performance.

p a t t e r n was

c o u l d be

fibers.

building

conventional

technology. m o d i f i c a t i o n has

markets where b u l k , quirements. thermal

yarns

able

b a s e d on

In

engineering

appropriate was

i n c r e a s e d demand

general

Physical

such

By

nylon,

fibers,

a d v a n c e s h a v e o p e n e d h u g e new

blocks which

by

direction.

a e s t h e t i c s and

steadily

fiber

a new

of molecular

were d e v e l o p e d

The

polyolefin

P r o f . Mark.

chemistry

have

into era

sound b a s i s w i t h

and

m o d i f i c a t i o n one

generation Fibers

established a polyacrylics

as

Improved b u l k or

false

mechanical t w i s t or

were o b t a i n e d

opened

t e x t u r e and

by

and

luster

up

very

t e x t u r e were

texturing using

jet texturing. combining

large

were prime

re-

achieved

processes

Self-crimping

polymers

with

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

8.

MAGAT AND MORRISON

Evolution

different

shrinkage

fibers

i n mixed

or

of

Man-Made

characteristics shrinkage

with

section

modification provided

attractive section

luster

options

industrial zation

attractive and

are

yarns,

new

tensile

giving

led to

Chemical solutions

t o major

novel

stability

modification of

chemical

examining

h a v e b e e n made advances

fibers. leads pill

poration

of

increased

dye

has

On

other

nylon.

the

resistance and

salts)

great deal

Major I.

i n Table

stronger lower

molecular

which

exhibit

fabrics.

sites

had

antioxidants

are

and

hand,

and

freedom

resistance

of

readily

Incorled

light from

by in

are

s m a l l amount o f

phthalic

i n place of

fiber,

multicolor

fabric

i n one

is

the

levels

"Sunburst" of

dye

containing and

we

generation many o f

the

development

dye

on

can

acid.

be

bath.

When

combined achieved A

striking

dyed

i n one

single

by

with dye

fiber

modifications is s t i l l

An

o f Qiana®

the

four

bath

dyes. the b e g i n n i n g

example

most d e s i r a b l e

single

illustration

of

fibers.

fibers dyeing

types

are witnessing

co-

sulfoiso-

i n one

carpet containing fibers

affinity

three

Research ing

single

i n c o r p o r a t e d by

adipic

effects

hiding.

controlled

f o r b a s i c dyes

are

static

c a r b o x y l ends

f o r example, dyeabilities

copper dura-

soil

polymerizing, acid

to

(e.g.,

through

amine and a

obtained advances

fibers

m o d i f i e r s to

dyes

effects

shown

led to

b a s i c dye

soil

for acid

different

of

polyacrylics.

to b e t t e r heat

the balance Sites

a

Similar

i n staple

versatility;

antistatic

Sites

are

weight

i n some c a s e s

changing

the

nylon.

technology

acidic

manganese

bility;

some o f

t o more b r i t t l e

improved

added

i n p o l y e s t e r s and

i n nylon

molecular

tougher

with

and

end-us

by

and

of

crystalli-

a l l

by

and

field

and

with

improved

m o d i f i c a t i o n has

to

illustrated

weight

processes

Some c r o s s the

properties.

versatility

Higher

In

Cross-

an

aesthetics.

fibers

with

yielded

bulk. with

i n F i g . 1.

drawing

yarns

These and

fabrics

tactile

sequences have

morphology

aesthetics

shown

i n bicomponent

yarns.

fabrics

131

Fibers

of

a

building

nylon which

of

fiber blocks

continu-

third combining is

the

exemplifies

the

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

132

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

Figure 1.

Cross-section versatility

TABLE POLYMER

HIGHER

MODIFICATION

MOLECULAR WEIGHT

INCORPORATION B A S I C DYE

I

OF A C I D I C AND

STRONGER F I B E R S DYE

VERSATILITY

SITES

ANTIOXIDANTS

HEAT D U R A B I L I T Y LIGHT DURABILITY

ANTISTATIC

MODIFIERS

FREEDOM FROM (SOIL

HIDING)

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

STATIC

8.

MAGAT AND MORRISON

purposeful fications

combination to yield

of

high

fibers.

The

contains

cyclohexane

recovery

p r o p e r t i e s and

polymer

f a r exceeding end-uses. The

tuned

and

filaments

i n a yarn bundl

hav

finishing,

providing fabrics as

capillary Another the

gives

w e l l as

spaces

facet

fiber a

temp-

by

the

f o r garments Qiana®

of

is

polymer

which

highe

in

for

the

modi-

some

shrinkag

tha

shrinkag

bulky

feel

feature of

spinning technology

This

high

encountered

combination

fications

which

to give

characteristics

self-bulking

finely

modi-

glass transition

temperatures

of

others.

polyamide

These p r o p e r t i e s account

ease-of-care

a

physical

self-bulking

i s designed

a high

outstanding of

and

for this

rings

erature

Qiana®.

chemical

performance

base

apparel

result

133

Evolution of Man-Made Fibers

that bring

of physical

shape

and

silk-like

with

a myriad

the

a

of

rich

handle

and

a

interfilament

about wearer

comfort.

m o d i f i c a t i o n i n Qiana®

particulate

additive

pearlescent luster

is

that

without

chalki-

ness. Another

direction

generation

fibers

structures

by

This sheet has

yarns

been

tinuous agent

and

coarse

we

a

this

initial

shown for

look

fabric.

to polyethylene

the

are

the

third

the

36

survey of

I t took

30

web

bonding

exceed as

fibers

over-all

years

from

t o c a t c h up

with

i n the United

man-made f i b e r s

a

w h e r e a web

o f major

The

1980 to

con-

where a

man-made f i b e r s

period.

i s expected

By

a

where

i s bonded w i t h

volume

expected

i n Tyvek®

i n Typar®

as

technology

generation derivatives,

growth

year

noncellulosics

their

This

of

self-bonded.

and at

spinning.

where

interconnected i n a

polypropylene is

new

down d i r e c t l y

t o p o l y e s t e r i n Reemay®

i n F i g . 2.

cotton. are

laid

complete

second

take

1976

spun and

filament yarns

fibers

As their

to

fiber

technology

nonwoven

network,

continuous

integrated with

spunbonded

fibers

of

sheet

or

applied fine

development

preparation of

are

structure

extremely of

a process

i s the b a s i s of

multiple

f o r the

i s the

10

t o be

compared

is

introduction cotton.

twice

lbs. of

to 4 b i l l i o n

during

picture

that

States alone

billion

and l e t us

In of

shipments

noncellulosic l b s . of

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

134

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

natural

fibers.

Table grown. and

I I shows how

Polyester

i s now

expected

second

t o be

these high

fast

i s by only

the

the

f a r the to

cotton.

number o n e

volumes the

four

major

By

fiber

1979

advantages of significant

and

p o s i t i o n of

these

carpet

started total

industry

carpets

will

million

l b s . of wool

price The

trend

force

Phase

as

For

equivalent,

f o r expanded

formance

i s at

At

a

the fibers. fiber

increased

magnitude.

the

In

1976

i s quite

a

short

time

than

of

is

i n 1974

cotton.

thus p r o v i d i n g

use

remarkable.

to cotton

polyester

a

illus-

polyester

Today

strong

they

driving

s t a p l e where

per-

premium.

about

the

same t i m e a s

generation

fibers

with

fibers,

an

entirely

fication

four basic

These

of

the

fibers

fibers

because

polyesters, yet

are

t h e y do

are

duplicate such as

of

not

have

or

utility

the

rubber,

glass

and

steel

these

E a c h new

chemical

represents product

f o r the

or

contrast

basic

pattern

fibers. was

to

materials

achieve heat

an

extreme

resistance,

resistance. a development

i s the

desired

f i l l

specialty

from b a s i c

c h a r a c t e r i s t i c s such as

f l a m e r e s i s t a n c e and Each of

fibers

of

polyamides

lbs. in

l b s . f o r the

i n i t i a l research of

to

these

of m i l l i o n s of

modi-

specialty

broad

for

properties

systems.

as

designed

of

shifted

physical

fiber

the

Markets

tens

properties

search

set of

chemical generic

m i l l i o n s of

again

performance

itself.

different

by

specifically

i n the

to hundreds Here

attention

p o l y a c r y l i c s , p o l y o l e f i n s , and

they are

development

sometimes r e f e r r e d t o

important market need. fibers

the

research

achieved

sive

now

compared

w h i c h c a n n o t be

but

four

IV

second to

polyester

a c t u a l l y cheaper

about

of

At

1.

i n F i g . 3.

s t a p l e was are

has

o f man-made f i b e r s

price of

trated

w o o l and

several orders

use

enhance

i s a good example where a

competing with

m a r k e t by

i t is

l a r g e - s c a l e manu-

favorable The

have

fiber

in textiles.

f a c t u r e become h i g h l y competitive

fibers

f a s t e s t growing

outcome o f

properties,

story an

in

inten-

understanding

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

8.

MAGAT AND MORRISON

1940 Figure

1945 2.

Evolution

1950

Growth

of Man-Made

1955 1960 YEAR

1965

135

Fibers

1970

1975

of man-made fibers vs. cotton in U.S.

TABLE I I GROWTH OF MAJOR FIBERS

(U.S.)

(MM LBS.)

NYLON

POLYESTER

ACRYLIC

OLEFIN

1950

90

0

1

0

1960

411

75

135

14

1970

1354

1465

491

255

2000

3000

600

500

1976

(PROJ.)

(COTTON:

3600)

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

136

of

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

the

mechanical

between fiber four

fiber

properties

chemical

properties. types

stage:

of

high

resistant

and

desired

This discussion

fibers

which

temperature

fibers,

have

be

reached

fibers

correlation

structure will

resistant

elastic

and

physical

the

fibers,

and

with

limited

to

commercial chemically

reinforcing

fibers. High

Temperature The

f o u r major

ture well apparel for

Resistant Fibers

below

200°C.

end-uses

extended

between

200°

carried

out

fibers

and

400°C.

over

the

relationships stability. candidates

are

are

by

linked

Typical

these

products

Table

III.

zoles and

industrial

acid

of

finally,

and

a

starts

with

benzimidazole

and

a

I f one

tetramine

in a

shown

in and

an

aromatic

tetramine

and

the

polybenzimida-

a diamine

with

is a

with

acid,

an

benzene

diamine

obtains

i s used the

ther-

for preparing

product

combines amide

where

acid,

uses

and

imidazole are

one

a dicarboxylic

tetracarboxylic

obtained which

and

aromatic

chloride,

been

defining

heat-resistant

reactions

an

at

structure

polymers

imide

dianhydride, the i f a

or

aimed

properties

with

obtained. acid

anhydride is

fiber

I f one

ester

are

aromatic amide,

Starting

polyamides.

polymer

chemical

and

dibasic

ten years

most p r o m i s i n g

fiber

aromatic

of

E x t e n s i v e r e s e a r c h has

past

between

The

rings

diphenyl

a number

tempera-

period

the

aromatic

For

a maximum u s e

fiber

mal

linkages.

have

a

an

polyimide;

a bis

ladder

properties

of

condensed

polymer a

heterocyclic

structure. The

major

commercial

Nomex®

aramid

1961.

I t i s prepared

dibasic

acid

followed

by

Related is

flame

sistance

w h i c h was chloride

solution

nylon

and

be

in this

solution

with

an

polymerization of

aromatic

In c e r t a i n

fully

polyester

in

resistance

requirements

cannot

is

by

fiber

s p i n n i n g from

to heat

resistance.

needs

end-use

introduced commercially

an

amide s o l v e n t .

a highly

are

so

severe

by

conventional

even

desirable

end-uses

met

fibers

that

after

a

diamine

they

flame

goal

re-

performance polyacrylic, are

flame

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TABLE HT HEAT RESISTANT FIBERS τ/Ε NH

2 v

x^NH

2

ClOC^^COCl

x ^ . N H - C O ^ ^ .

Η

co^oc

CO^OC

!

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

Î

9

P

d

/

%

)

138

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

retarded.

These

structures

which a r e d i f f i c u l t

relatively

high

Nomex® Fibers and

end-uses

dictate

meets

this

and

requirement

tection

Nomex®

i s now b e i n g

clothing

from char

In total

certain

from

by Nomex®

behavior

i n flames,

exposure

f o r such

Nomex®

III.

exhibit

very

A by

i s based

precursor

fusible,

For

flame

t o high

flux,

thereby

such

Nomex® I I I

open and

maintaining

ana i r

characteristics

with

on

tech-

no s a c r i f i c e

as comfort,

of

of

abrasion

resistant

fiber

i n 1970.

i s a novolac

formaldehyde

was

introduced

The f i b e r

named

phenol-formaldehyde. which

and cured

i s later to give

posta non-

fiber.

Resistant Fibers

certain

a very

1960

Teflon®

the high

insulation

t o as

spinning

heat

on a c r o s s l i n k e d

fiber

with

with on

beyond

i n 1971 i s b a s e d

a n d o n new

attributes

of

t o supplement

referred

The p r o t e c t i o n

nonflammable

Chemically

pro-

coloration.

new h i g h

crosslinked

unique

these

total

fiber

i s now

low s h r i n k a g e ,

and

Under

s t r e n g t h , do n o t b r e a k

layer. fabric

protection

introduced

t h e C a r b o r u n d u m Company

The

of a

a thick

i s the key.

a new

I I I have been o b t a i n e d

"Kynol"

key

fiber

When s u b j e c t e d maintain

important

uses,

Pro-

lightweight fabrics

flux

which

polyamide

fabrics

resistance

produces

open thus

heat

uses

This

aromatic

Nomex®

and i n d u s t r i a l in aircraft.

i s desired.

Du P o n t h a s d e v e l o p e d

insulating

e x t e n s i v e l y used i n

conditions short-term

high

Nomex®

nology.

smoke

o f i t s flame

i s the r e s u l t

which

degree.

little

catastrophi

b y Nomex®

extremely

new

to a high

generate

formilitary

s h r i n k and break

offered

extreme

to

upon exposur

immersion

Nomex® that

flame

and f a b r i c

tective

polymer

and s t a b l e

As a r e s u l t

i n c a r p e t i n g and u p h o l s t e r y

fiber

a

to ignite

to ignite,

are self-extinguishing.

resistance,

with

temperatures.

are d i f f i c u l t

protective

fibers

high

industrial level

fibers

end-uses

o f chemical

were

fibers

a r e needed

resistance.

introduced which

In

capitalized

inertness of polytetrafluoroethylene.

a d v a n c e was

the discovery of technology

The

f o r con-

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

8.

MAGAT AND MORRISON

verting

an

ethylene of

a

dispersed

Elastic

and

put

In

the

search

fiber

could

be

Thus,

one

the

polymers

would

viscose

solution

or

toughness.

by

was

the

selected

as

and

of in a

They

giving

the

best

form

cyanate

to

give step

an

product

or

a

i s a high

the

the

the

molecular polymers

fibers

polymers segment

of

product

Lycra® soft

hard

of

were

intro-

fiber

block, of

final

The is

the

soft

aromatic

diiso-

prepolymer.

segmented

polyurethane

chain

extension

reaction

polymer

having

urethane

soluble

in

be

at

prop-

was

form o f

readily

reinhigh

segment.

terminated

weight

as of

polyurethanes

type

The

are

act

elastomer

segment by

i n the

can

alternating

hard

excess

the

diamine.

linkages.

These

this

hard

sites

and

1958

an

i n preparing

hydrogen bonding solvents

In

isocyanate

synthesis of

hydrazine

as

f

program aimed

as

for preparing To

an

balance

polyether

TV.

of

segment m a t r i x

processibility. a

The

extensive

i s end-capped w i t h

final

featur

melting

composition,

segment

the

polymers.

crosslinking

consist high

to g i v e

an

block

i n Table

to

essential

soft

best

scheme

fibers

non-crosslinked

resort

"hard"

particles

utilizing

general

to Th

stable

elastic

elasti

Following

defining

with

spinning

followed

and

that

amorphous p o l y m e r s .

filler

erties

have

strong

was

linear

nature.

blocks

"soft"

forcing

is

wet

use.

sheer,

finding

from

domains d i s p e r s e d

The

on

dispersion

commercial

rubber

giving

segments

shown

polytetrafluoro-

in a

for a

not

segmented

duced

as

based

key

prepared

conventional

with

such

process

Teflon®

139

Fibers

A

the

to

Man-Made

Fibers

elastic

their

of

of

polymer

fiber.

coalescence

developed

in

intractable

into

Teflon®

heat

Evolution

or

urea

amide

prepared

by

dry

spinning. This has

been

segment

general refined

structures of

aromatic

the

functional

This and

has

polyethers a

using and

variety

resulted in fibers

mechanical

hydrolytic

elastic

years

d i i s o c y a n a t e s and

tenders. color,

pattern of over

fiber

formation

optimum

soft

polyesters, of of

chain

ex-

improved

p r o p e r t i e s i n c l u d i n g improved

stability

and

UV

stability,

high

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

Extension

0

II

c-o

+

Η

Η

Η

+ H N - R ' — NH

Ο

2

OH

Η

Ο

II

Η

Η

I

Η

O - C - N - R - NCO

- CH

2000

2

ο

•«

ο

»

ο

H

ο

il

O-C-N-R-N-C-N-R'-N-C-N-R-N-C-O-

Η

~

2

OCN-R-NCO

MW

2

H Ο - CH CH CH

OCN - R - N - C - O

Macroglycol

Segment

Capping-

Chain

End

Soft

TABLE I V

ο

Ι -Q~C „

,

, V

ο

1

MAGAT AND MORRISON

8.

power, h i g h

e l o n g a t i o n and

Reinforcing

Fibers

A

rapidly

fibers

i s the

reinforcement technology fibers. through

a

and

led

to

not

be

steel and

new

fibers of

by

met

with

The

new

their

advent

suited

this

high

has

are

shown

modulus o f

the

new

thus

curves

of

graphically

shown

Kevlar®

of

or

only

one

belt

yarns

tire

yarn

must

flex

life

and

these

5

with

stiffness

ease

Reinforcement fibers

i s receiving

of

rapidly

posites. yield

offer of

i t s low

On 2

of

Reinforcement

advanced

a

by

tire

of

strength, nylon

of

or

is

yarn.

For

importance.

The

adhesion,

Kevlar®

meets

degree.

continuous

technology

pro-

are

Tensile strength

remarkable

composites

and

density

glass,

increased attention

growing

organic

fibers

good b a l a n c e

resins

properties

the b a s i s of

lbs. of

i s o f major a

an

a fiber,

Tensile

processibility.

to a

they

reinforcement

for tire

l b s . of wire.

also

and

strength

superiority.

replace

of

tire

high

consideration in selecting high

glass

steel.

i n F i g . 5.

requirements

the

levels

affording

The

combined

can

and belts

introduction of

major

i n F i g . 4.

Kevlar®

Glass

for tire

While

has could

m o d u l u s man-made o r g a n i c

strength-modulus r e l a t i o n s h i p s

polyester,

rayon, were

tires

fibers.

The

provided

strong margin

l b . of

rein-

desired properties,

to glass or

Stress-strain

1

fibers

radial

market.

for tires,

alternative

of

organic

limitations.

tenacity, aramid,

a

tire

for

progressing

including

these

required stiffness

captured

ideally

vides

the

p e r f o r m a n c e demands w h i c h

existing the

Kevlar®

fibers

markets

specia

c o n t r i b u t e some o f

fiber

largest

c o t t o n and

In general

The

is a well-established

the

with

filament

resins.

for textil

stringent

high

of

and

synthetic fibers

for tires.

have

rubber

have dominated

series

polyester.

provided

steel

one

starting

rapidly

also

provides

adapted

suitable

f o r continuous

of

for tires

field,

engineered quently

recovery·

market

of rubber

Organic

forcement nylon

expanding

high

reinforcement

and

141

Evolution of Man-Made Fibers

of

filament the

advanced

thermosetting initially

as

basis com-

resins

started

with

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

to con-

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

STRAIN (%) Figure 4.

Tire yarn stress-strain

curves

KEVLAR®

NYLON POLYESTER f

QGLASS

RAYON •WIRE

100

200

DENSITIES NYLON POLYESTER KEVLAR® GLASS WIRE

_L_

300

_L

400

1.14 1.38 1.45 2.55 7.9

500

600

MODULUS (gpd) Figure

5.

Tensile

strength-modulus fibers

rehtions

for

tire

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

8.

MAGAT AND MORRISON

tinuous ratio of

filament glass.

of

tensile

structural High

The

major

modulus

With

at

fibers

lower of

of preparing

the

Kevlar®

organic

fibers

stress-strain Fig.

tensile

comparison

shown

the

third

matrix

as

aluminum

to

to

improve

fibers

Let

us

fibers

are

polymeric

increase

take

a

heated

reach to

i s to such and

temper-

filament

well

as

preparation

fibers.

graphite.

Cellulose

the

main

thermal

flameproof

Orion®.

and

a temper-

polyof

carbon

properties obtained (PAN)

continuous-

Three process

the

steps

carbonization first

step

the

and PAN

structure originally

Carbon

highest

1400-1800°C

In

of

high

source

pretreatment,

treatment.

and

Graphite

decomposition f o l l o w e d by

polyacrylonitrile

their

elevated as

the

to graphite yarns.

to a

metals

drive

i n metals

continuous

at

i l l u s t r a t e s the

high-temperature

using

The

fibers

Kevlar®

have p r o v i d e d

involved:

process

look

and

thermal

known a s b l a c k

specific reflect

intensively

carbon

of

A

advanced

strength vs.

boron

to

yarns

compare

These values

stiff

by

upon c o n v e r s i o n

to

for

reinforcement

prepared

Fig. 8

fibers

properties at

quick

to

used

cross-section.

weight.

precursor

converted

with

fibers.

graphite

conversion

filament

named

stiffness-to-weightratio

explored

alumina

acrylonitrile fibers.

the

weights.

Kevlar®

in i t s infancy.

g r a p h i t e and

of

equal

these

fiber

tenacity,

are being

properties

of

equal

of

retention of

Here

experimental

possi-

matching

u n i t s are of

specific

is still

high

atures.

of

sparked

the

compete d i r e c t l y

i n F i g . 7.

area

incorporate

are

now

fibers

properties at

The

ature

of

i s to plot as

have

curve

more r e a l i s t i c stiffness

boron

composites

is

stiffness.

i

strengths

composites

glass

in

offering

a variant

fibers

ratio

properties of

c o n s i d e r a b l y lower

6 where p s i e n g i n e e r i n g

tensile

as

at

by

high

a high

While

g r a p h i t e and

introduction of

inorganic

the

143

is a

and

weights.

advanced

of metals

49,

goal

i t i s somewhat d e f i c i e n t

materials/design revolution

properties

Fibers

strength-to-weight

metals

strong,

bility

is

of Man-Made

stiffness-to-weight to achieve

quite a

Evolution

fibers

tensile

( G r a p h i t e HT)*

made b y

the

PAN

s t r e n g t h when There

is

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

direct

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY 600

TENSILE STRAIN (%)

Figure

6. Stress-strain

behavior

of reinforcing

fibers

"KEVLAR"49

"S"-GLASS

HT G R A P H I T E

BORON H M GRAPHITE* φ "Ε"—GLASS

1

2

3

DENSITY (gm./cc.) "KEVLAR" 49 1.45 GRAPHITE HT 1.78 GRAPHITE HM 2.0 BORON 2.68 "S"-GLASS 2.48 _L 4 5 6

7

SPECIFIC T E N S I L E MODULUS (10 IN) 8

Figure

7. Specific tensile strength modulus of reinforcing

and specific fibers

tensile

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

MAGAT AND MORRISON

)l

1200

Evolution of Man-Made Fibers

ι

ι

1600

ι

ι

e

C

2000

1

1

2400

—lo

EZEKIEL, H.M., AIR FORCE MATERIALS LABORATORY. T R - 7 0 - 1 0 0 , JANUARY 1971

Figure 8.

Effect of heat treatment temperature on the mechanical properties of carbon fibers at room temperature

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

146

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

correlation stage

and

process

between

tensile

incorporates high

stretching

at

( G r a p h i t e HM) tensile been

high

modulus a

aromatic

spinning

process

of

transition

exceeding

have

economical

a highly rigid prepared

by

favors alignment

temperature)

500°C.

as

200 ° C .

a

para-

novel

of

extended

of

the

characteristics

or

of

creep

jD-oriented

crystalline directly

extended

and

to is

outstanding,

aromatic

poly-

s o l u t i o n s which

high

no

be

temperatures

highly oriented

fibers

can

temperatures

at

polymer

c h a i n and

these

300°C

stability

shrinkage Rigid

liquid

above

or m e l t i n g

Dimensional no

spinning yield

Because

from

polyamide

decomposition

essentially

amides g i v e upon

a potentially

structura

without

high

lower

fibers

fibers. fiber which

(glass

as

the

chains

degree

with

as

pitch

If and

fibers

somewhat

More r e c e n t l y ,

attention

oriented

heated

treatment

with

is a

polymer

temperature

obtained

to graphite

rigid

pretreatment

carbonization.

2400-2500°C,

strength.

Kevlar®

i n the

are

receiving

route

stretching

strength after

fibers.

crystallinity

further

drawing

is

needed. Let for in

us

now

Kevlar®. two

and

types

Kevlar®

consider

Beyond The

first

creasing

uses

at one-fifth

garments law

such

i n ropes

injury

or

armor o f from

used

to reinforce

boat

hulls

equipment With

including such the

as

modulus p r o p e r t i e s w i t h organic limits organic

fibers; of

are

and

we

The

strong

nine

months instances

prevented

Kevlar®

49

serious

i s now

kayaks,

and

sport

and

golf

extremely

K e v l a r ® , we ask

high

are

reaching

attainable

maximum c o h e s i v e

clubs.

tensile with

o u r s e l v e s what a r e

stiffness

being

structures,

tennis racquets of

29

in-

as

that achievable heretofore

s t r e n g t h and

fibers.

has

and

Kevlar®

In recent

f o r aerospace

canoes

attainment

range w e l l beyond

29

available

in protective

have r e p o r t e d

gunshot.

skis,

and

vests.

is

i s finding

cables which

Kevlar®

resins

end-uses p r o j e c t e d

called

these

weight

as b a l l i s t i c

death

the

Kevlar®

fibers of

and the

enforcement o f f i c e r s

where body

yarns

of reinforcing 49.

as

steel

some o f

tire

the

with

force i n a

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

a

and

8. MAGAT AND MORRISON

Evolution

polymer

such

rupture

o f C-C b o n d s

ethylene

of Man-Made

as p o l y e t h y l e n e would

chains

i n a polymer

a r e packed

t h e C-C d i s s o c i a t i o n

packing

of polyethylene

strength

corresponding

would be r e a l i z e d were c o m p l e t e l y flaws for

not

t o each

one c a l c u l a t e s i fpacking

uniform

a maximum

T h i s maximum

value

o f the molecules

and r e g u l a r l y

arranged

The h i g h e s t

i s 23 g p d c o r r e s p o n d i n g

other.

and t h e c r y s t a l

values

without reported

polyethylene

t o a strength

fila-

smaller

maximum b y a f a c t o

been

ascribed to a perfectly

over

parallel

and do n o tb r e a k

simultaneously

t h e same c r o s s - s e c t i o n , (b) i m p e r f e c t i o n s

structure

and chain

a statistically then

ends

Using

principles

values

with

have been force

constants

other

on c r y s t a l

polymers,

calculated f o r

V.

One r e l i e s o f bonds lattice

stressed fibers.

compared

with

attainable with

values

ultimate

polyamides

i n t h e polymer extensions

The spread

based on

chain

VI observed

calculated

and t h e by x-ray

moduli a r e

b y T r e l o a r and

between

t h e o r e t i c a l and than f o r

F o rjD-oriented

strengths.

the theoretical

techniques

observed

i s c o n s i d e r a b l y narrower

tensile

study

Two

on c a l c u l a t i o n s

In Table

values

Fielding-Russell.

Future

breakage.

on other

t h e work o f P r o f . Mark.

used.

which

propagates

polymers has r e c e i v e d c o n s i d e r a b l e

starting

almost

bonds

crack

have been

i n Table

i n the

concentration

few chemical

initial

s u b j e c t o f u l t i m a t e modulus

organic

actual

to stress

leading t o fiber

a s shown

The

This

similar

maximum t e n a c i t y polymers

lead

favored

ruptured.

catastrophically

on

energy

h i g h l y o r i e n t e d and c r y s t a l l i n e

than

are

only

to

where a l l p o l y -

t o 250 g p d .

or discontinuities.

ments

on

correspond

parallel

Knowing

147

Fibers

limit

aromatic

of stiffness i s

reached. o f Man-Made F i b e r s

Where d o we s t a n d now a c h i e v e d

today?

a s t a t u s which

when n y l o n was i n t r o d u c e d made f i b e r s

range

fibers

spandex

like

from

Man-made

looked

i n 1940.

fibers

P r o p e r t i e s o f man-

low modulus, h i g h

t o high

have

barely possible

modulus, h i g h

elongation tenacity

American Chemical Secioty Library In Textile and PaperIGth Chemistry and Technology; Arthur, J.; 1155 St. N. W. ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

V

Black

(2)

and

and

Preston

Mark (1973).

(1971).

AROMATIC

^-ORIENTED

Tobolsky

66

POLYAMIDE

(1)

200

2G-T

POLYESTER

165

215

250 g p d

POLYETHYLENE

POLYAMIDE

FOR

THEORETICAL

MAXIMUM T E N A C I T Y VALUES

TABLE

(1)

REF,

FIBERS

(-28)

10

10

23

ACTUAL (2)

REF,

5

ο

ι

a

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

Marcel

Loc.

Loc.

(2)

Black,

(3)

(1)

POLYAMIDE

JD-ORIENTED

W.B.

and

Cit.,

Cit.,

p.

p.

Dekker,

35.

21.

I n c . , N.Y.,

J.,

1500

950

m-ORIENTED

AROMATIC

400

CELLULOSE

Preston,

2G-T

POLYESTER

AROMATIC

1780

66

POLYAMIDE

950

2060

POLYETHYLENE

POLYAMIDE

VI

1973, p.

13.

1400

175

200

150

50

430 (3)

Fibers",

REF«

Aromatic

ACTUAL

FIBERS

Wholly

FOR

"High-Modulus

(2)

(2)

(1)

(1)

(1)

(1)

REF.

(IN/GPD)

MODULUS V A L U E S

THEORETICAL

MAXIMUM

TABLE

150

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

fibers

e x e m p l i f i e d by Kevlar®.

combination The

outlook

man-made f i b e r s

f o rcontinued continues

Emphasis w i l l polyamide, still

a very

promising.

comfort,

fibers

to provide

dye v e r s a t i l i t y and

performance.

search

f o rspecialty

fibers

limits

man-made f i b e r s .

expensive

strating the

and p o l y o l e f i n

goal of identifying

able with

growth and advances i n

t o be h i g h l y

better aesthetics, The

almost any

engineered.

b e t o improve o u r major p o l y e s t e r ,

polyacrylic

ease-of-care the

I n between,

o f properties can be

will

Developing

and length

continue

o f performance

with

attain-

a new f i b e r i s

undertaking

Demon

one s i n g l e

fiber

t o b e s u c c e s s f u l must b e c o s t - c o m p e t i t i v e ,

must halre a g o o d b a l a n c e

o f p r o p e r t i e s and be f r e e o f

any

end-use c o n d i t i o n s .

major n e g a t i v e As

of

fibers

textiles.

entirely

new l e v e l s

been achieved

i n fiber with

science

technology

Kevlar® will

new d e g r e e s

new l i m i t s

beginning

combinations

will

spread

to capitalize

up b y f i b e r

reinforcement.

and g r a p h i t e f i b e r s . new f i b e r s

evolve

With

a new m a t e r i a l

a l l o w i n g d e s i g n e r s and

o f freedom

leading to entirely

of technological feasibility.

Fibers new e n d - u s e s

a l r e a d y have been developed such

as o p t i c a l

s e m i p e r m e a b l e membranes, fibers

of

impact

s t r e n g t h and s t i f f n e s s has

a v a i l a b i l i t y o f these

engineers

their

We a r e j u s t

t h e p o s s i b i l i t i e s opened

A breakthrough the

with

p r o p e r t i e s a r e developed,

beyond on

under

o f the type

used

fibers,

for entirely

hollow

and low d e n s i t y i n "Pneumacel"

fibers

as

pneumatic

cushioning

materials. The great

producers pected of

f u t u r e o f man-made f i b e r s

will

depend

degree on r e s e a r c h accomplishments by and t h e t e x t i l e

breakthroughs,

industry.

prospects

e v o l u t i o n a r y growth t o reach

polyesters,

polyamides,

Short

ina

fiber o f unex-

are f o ra long period the f u l l

polyacrylics,

potential

and

of

polyolefins.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

9 Nonfuming Spin Finishes WARREN A. SCOTT ICI United States Inc., Wilmington, DE 19897

The recent impact of OSHA on the textile industry has greatly influence for textile finishes. One of the more dramatic changes has been toward requirement of totally "nonfuming" spin finish systems. A limited number of c r i t i c a l areas where nonfuming finishes are of particular interest include feeder yarn for texturing applications, bulked yarn such as BCF nylon and acrylic, industrial yarns, and hot drawn nylon. The range of temperatures encountered in these areas is approximately from 280° F (140°C) to 410° F (210° C ) . As fiber finishes are generally multicomponent mixtures of organic chemicals, i t is virtually impossible to design a finish system that is totally nonfuming. So this paper w i l l mainly deal with the optimization of a system to provide the performance properties with a minimum of fuming at the desired processing temperatures. A typical finish system consists of: 1. Lubricant (40-60%) 2. Emulsifier(s) (15-35%) 3. Antistat (10-25%) Minor ingredients usually added to provide a more specialized function may include: 1. Friction Modifiers 2. Antioxidants 3. Biocides 4. Viscosity Modifiers These minor ingredients are used in small quant i t i e s when compared to the use of the f i r s t three, usually 1-5% and seldom more than 10% of the total 153

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

154

TEXTILE

AND PAPER

CHEMISTRY AND

TECHNOLOGY

formulation. T h i s paper w i l l d e a l o n l y w i t h the major i n g r e d i e n t s , b e g i n n i n g w i t h the l u b r i c a n t , which i s us u a l l y the l a r g e s t p a r t of the s p i n finish· N o t e , t h a t a s an i n i t i a l measurement o f f u m i n g , t h e AOCS smoke p o i n t ( C c - 9 4 0 ) i s u s e d a s a g u i d e . Ind u s t r y e x p e r i e n c e has i n d i c a t e d t h a t i n - p l a n t fuming w i l l not occur u n t i l r o u g h l y 35° F - 50° F above the v a l u e o b t a i n e d b y t h e AOCS smoke p o i n t m e t h o d . 300° F h a s b e e n c h o s e n a s a minimum t e m p e r a t u r e f o r n o n f u m i n g finishes; t h i s c o r r e l a t e s w e l l w i t h what i s f o u n d i n industrial practice. A series of vegetable o i l lubric a n t s m e e t i n g t h e smoke p o i n t c r i t e r i a a r e l i s t e d below: Lubrican Safflower O i l 475 Peanut O i l 460 Cottonseed O i l 455 Soybean O i l ( p a r t i a l l y 440 hydrogenated) Coconut O i l ( r e f i n e d ) 360 Olive O i l 325 B u t y l Stéarate 205 Mineral O i l 185 B u t y l s t é a r a t e a n d m i n e r a l o i l smoke b e l o w 3 0 0 ° F , o b v i o u s l y , but they a r e i n c l u d e d f o r comparison bec a u s e they have e x c e l l e n t f r i c t i o n p r o p e r t i e s and a r e economical, hence they are w i d e l y used d e s p i t e t h e i r f u m i n g p r o p e r t i e s . The f r a c t i o n a l p r o p e r t i e s o f t h e s e lubricants are given i n Table I. The d a t a i n t h i s t a b l e were o b t a i n e d w i t h t h e ATLAB F r i c t i o n T e s t e r u s i n g ASTM D-3108-32 ( f o r y a r n t o - m e t a l f r i c t i o n ) a n d D-3412-32 ( f o r y a r n - t o - y a r n friction). T h e HH f i g u r e s i n t h e s e c o n d c o l u m n a r e a measure o f y a r n - t o - y a r n c o h e s i o n , an i m p o r t a n t quality t o p r e v e n t s l u f f i n g o f y a r n s on t h e p a c k a g e . A n a l y s i s o f t h e d a t a i n d i c a t e s t h a t many v e g e t a b l e o i l s w i l l meet t h e f i b e r - t o - m e t a l f r a c t i o n a l p r o p e r t i e s r e q u i r e d f o r the f o r m u l a t i o n o f nonfuming f i n i s h e s of the type t r a d i t i o n a l l y b u i l t around mineral o i l or b u t y l stéarate. Note a l s o t h e s i m i l a r y a r n - t o y a r n f r a c t i o n a l c h a r a c t e r i s t i c s e x i s t i n g w i t h most o f t h e l u b r i c a n t s w i t h h i g h smoke p o i n t s . The a r e a o f most c o n c e r n f o r f i n i s h f o r m u l a t i o n i s t h e amount o f c o h e s i o n o f f e r e d by t h e v e g e t a b l e o i l s . Three o f the

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

SCOTT

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155

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Frictional Properties Compared t o B u t y l

TABLE I of Various Vegetable O i l s S t é a r a t e and M i n e r a l O i l T

Product Yarn-to-Yarn Safflower O i l Soybean O i l Peanut O i l Coconut O i l Coconut O i l B u t y l Stéarate Mineral O i l 4

5

+ 0 + 8 + 13 + 16 + 15

28 26 25 22 23

2

f

As

(grams)1 3

Yarn-to-Metal 10m/min 50m/min lOOm/min 272 232 184 56 64 60 46 60 60 48 44 34 34 54 40

f 2 - i where T = 15 g r a m s . Y a r n - t o - Y a r n c o n t a c t a n g l e = 180°; yarn speed = 1 cm/min. Yarn-to-Metal ( s t a i n l e s s steel) contact angle = 180°; y a r n s p e e d = 10, 5 0 , a n d 100 m e t e r s / m i n . R e f i n e d coconut o i l - melting point = 76°. R e f i n e d coconut o i l - melting point = 92°. T

=

T

T

x

2

3

4

5

lubricants w i l l o f f e r cohesion levels bordering those o f f e r e d by m i n e r a l o i l , b u t n o n e a r e a s h i g h a s b u t y l stéarate. Many s y n t h e t i c p r o d u c t s a l s o o f f e r n o n f u m i n g p r o p e r t i e s m e e t i n g o u r smoke p o i n t r e q u i r e m e n t s , a n d while t h i s l i s t w i l l vary throughout the i n d u s t r y , we s h a l l c o n s i d e r a few p r o d u c t c l a s s e s . F i r s t we c o n sider a l i m i t e d series of t r i e s t e r s of t r i m e t h y l o l e t h a n e and p r o p a n e . AOCS Smoke Product T r i m e t h y l o l ethane t r i p e l a r g o n a t e T r i m e t h y l o l propane t r i h e p t o n a t e T r i m e t h y l o l p r o p a n e t r i C a 8-10 T r i m e t h y l o l propane t r i l a u r a t e

Point, °F 305 310 310 310

A l l o f t h e s e p r o d u c t s have "neo" structures, w i t h o n e c a r b o n h a v i n g no h y d r o g e n a t o m b u t attached only to other carbons. This probably gives these p r o d u c t s b e t t e r heat s t a b i l i t y , but l a b o r a t o r y studies h a v e shown t h a t f u m i n g p r o p e r t i e s a r e s t r o n g l y d e p e n d ent upon p u r i t y i n terms o f r e s i d u a l a c i d i n the f i n a l product. Thus i t i s e x t r e m e l y i m p o r t a n t t h a t good vacuum s t r i p p i n g be e m p l o y e d d u r i n g production.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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again

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CHEMISTRY

AND

TECHNOLOGY

Table II g i v e s f r i c t i o n a l p r o p e r t i e s of these, compared t o b u t y l s t é a r a t e and m i n e r a l o i l . TABLE I I Frictional Properties Tf

Product

Yarn-to-Yarn

TME t r i pelargonate TMP t r i l a u r a t e TMP t r i heptanoate TMP t r i C a 8-10 B u t y l stéarate Mineral O i l

Yarn-to-Stainless Steel 10m/min 50m/min lOOm/min

34 34

+ 22 + 14

52 48

72 68

120 112

34 27 27

+ 22 + 23 + 15

36 32 48

90 40 120

112 42 160

The f i b e r - t o - m e t a l f r i c t i o n a l p r o p e r t i e s o f t h e s e products are s u i t a b l e f o r l u b r i c a n t bases f o r use i n t h e f o r m u a l t i o n o f s p i n f i n i s h e s , b u t as w i t h t h e v e g e t a b l e o i l s , none o f f e r s l u b r i c i t y p r o p e r t i e s e q u a l to b u t y l stéarate. Another c l a s s of l u b r i c a n t s that a l s o ondary usage as e m u l s i f i e r s a r e f a t t y a c i d p o l y o x y e t h y l e n e and p o l y e t h y l e n e g l y c o l .

POE POE POE POE POE POE POE

POE

Product Γ7] P e l a r g o n a t e Î9] P e l a r g o n a t e fôj L a u r a t e f9} L a u r a t e C7] O l e a t e C8] O l e a t e C8] S t é a r a t e f40J S t é a r a t e

have a esters

AOCS Smoke P o i n t , 270 315 286 300 275 308 250 336

secof

°F

Smoke p o i n t s a n d f u m i n g p r o p e r t i e s o f t h e s e p r o d u c t s w i l l v a r y e x t e n s i v e l y depending upon the ethylene oxide or polyethylene g l y c o l chain length. I n g e n e r a l , PEG e s t e r s w i t h m o l e c u l a r w e i g h t s o f g r e a t e r t h a n 400 and p o l y o x y e t h y l e n e e s t e r s w i t h 9 o r m o r e m o l e s o f e t h y l e n e o x i d e w i l l m e e t t h e smoke p o i n t requirement. While the r e l a t i o n s h i p i s not a b s o l u t e , a p e a k a p p e a r s t o b e r e a c h e d a t a b o u t 15-20 m o l e s o f e t h y l e n e o x i d e and PEG m o l e c u l a r w e i g h t o f 650-750.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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Table the

157

Nonfuming Spin Finishes

I I I shows f r i c t i o n a l

more t h e r m a l l y

stable products

chemicals.

i n this

o f a few o f class of

TABLE I I I Frictional

Product

properties

Properties T f (grams)

Yarn-to-Yarn

Yarn-to-Stainless lOm/min 5Qm/min

POE [9] Pelargonate POE ψ\ L a u r a t e POE 18] O l e a t e B u t y l Stéarate Mineral O i l

25 23 19

+ 19 + 7 + 11

72 74 152

Steel IQQm/min

168 188 256

192 108 280

_

Many o t h e r c h e m i c a l s c a n b e u s e d t o m e e t t h e n o n fuming l u b r i c a n t p r o p e r t i e s necessary f o r u s e as a b a s e i n f o r m u l a t i n g s p i n f i n i s h e s . Not a l l c a n be discussed here because o f l i m i t a t i o n s , but products being used include: T e t r a e s t e r s o f p e n t a e r y t h r i t o l (which a l s o contain neo-carbon s t r u c t u r e s ) Mono- a n d d i - e s t e r s o f g l y c e r o l Mixed f a t t y a c i d e s t e r s o f p r o p y l e n e and ethylene oxide Polyoxyethylene castor o i l derivatives F r i c t i o n a l p r o p e r t i e s may b e m o d i f i e d b y b l e n d i n g many o f t h e p r o d u c t s m e n t i o n e d a b o v e . For instance, a h i g h e r l e v e l o f y a r n c o h e s i o n c a n o f t e n be a c h i e v e d by t h e a d d i t i o n o f POE f a t t y a c i d e s t e r s ; on t h e o t h e r h a n d , many p o l y o x y e t h y l e n e c a s t o r o i l s w i l l s e r v e t o e f f e c t i v e l y reduce the l e v e l o f yarn-to-yarn friction. Some o f t h e l u b r i c a n t s m e n t i o n e d u p t o t h i s p o i n t are not water s o l u b l e or d i s p e r s i b l e , and s i n c e t h e a p p l i c a t i o n o f most s p i n f i n i s h e s a r e f r o m a n a q u e o u s medium, t h e s e l e c t i o n o f p r o p e r e m u l s i f i e r s b e c o m e s important. Few e m u l s i f i e r s a r e g o o d l u b r i c a n t s , a n d many d o n o t h a v e l o w f u m i n g p r o p e r t i e s . There a r e so many t y p e s o f e m u l s i f i e r s we s h a l l o n l y c o n s i d e r c e r t a i n ones w i t h wide i n d u s t r y a c c e p t a n c e . Also, i t i s important t o recognize that other l u b r i c a n t s a r e water s o l u b l e a n d a l s o may s e r v e a d u a l p u r p o s e o f e m u l s i f i cation. Examples o f t h e s e would be found i n t h e c l a s s of p o l y o x y e t h y l e n e and p o l y e t h y l e n e g l y c o l f a t t y a c i d esters discussed earlier.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

The s e l e c t i o n o f e m u l s i f i e r s f o r s p i n f i n i s h s y s t e m s i s made e a s i e r a l t h o u g h s t i l l n o t s i m p l e , t h r o u g h t h e p r a c t i c a l u s e o f t h e A t l a s HLB S y s t e m . T h e l e t t e r s HLB s t a n d f o r H y d r o p h i l e - L i p o p h i l e B a l a n c e , T h i s s y s t e m h a s b e e n t h e s u b j e c t o f many p a p e r s , s o l e t us s i m p l y d e f i n e i t as a system t h a t e n a b l e s you t o a s s i g n a number t o t h e i n g r e d i e n t o r c o m b i n a t i o n o f i n g r e d i e n t s y o u want t o e m u l s i f y a n d t h e n c h o o s e an e m u l s i f i e r o r b l e n d o f e m u l s i f i e r s h a v i n g t h i s same number. While the system i s not f o o l p r o o f , i t i s useful i n narrowing the range o f e m u l s i f i e r s e l e c t i o n s . S i n c e we h a v e a l r e a d y e s t a b l i s h e d a d e s i r e t o h a v e o u r f i n a l product exhibi to d i l u t e r e a d i l y i ers o r c o m b i n a t i o n s o f e m u l s i f i e r s s h o u l d b e made f r o m o i l - i n - w a t e r e m u l s i f i e r s , a n d h a v e an HLB o r c o m b i n e d HLB i n t h e r a n g e o f 8-18, b u t m o r e t y p i c a l l y 9 - 1 3 . T h u s , we now h a v e two r e s t r i c t i o n s when d e a l i n g w i t h e m u l s i f i e r s , t h e f i r s t , "nonfuming", t h e second, " m e e t i n g t h e r e q u i r e d HLB". One o f t h e m o r e p o p u l a r a n d l o n g u s e d s e r i e s o f e m u l s i f i e r s meeting nonfuming requirements a r e the a l k y l a r y l e t h e r s , m o r e commonly r e f e r r e d t o a s e t h oxylated nonyl phenols. As shown i n T a b l e I V , a n i n c r e a s e i n AOCS smoke p o i n t i s n o t e d w i t h i n c r e a s e s i n the p o l y o x y e t h y l e n e c h a i n length which corresponds w i t h a n i n c r e a s e i n HLB. TABLE IV Ethoxylated Nonyl Phenols Product POE POE POE POE

[5j \jS\ [8] [9]

POE[loi P0E[l5J P O E [3d]

nonyl nonyl nonyl nonyl nonyl nonyl nonyl

AOCS Smoke phenol phenol phenol phenol phenol phenol phenol

280 272 315 332 282 335 275

Point

HLB 10 10.9 12.3 13 13.3 15 17.1

S e v e r a l u s e f u l p r o d u c t s meet t h e e s t a b l i s h e d HLB a n d smoke p o i n t c r i t e r i a . The major advantages f o r t h i s type o f e m u l s i f i e r a r e economics and v e r s a t i l i t y . One p o s s i b l e d r a w b a c k i s t h a t many d o n o t a p p e a r to b e r e a d i l y b i o d e g r a d a b l e , a l t h o u g h t h e d e f i n i t i o n s ) of biodegradability are s t i l l subject to

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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debate. A second s e r i e s o f e m u l s i f i e r s having wide u t i l i t y a r e the p o l y o x y e t h y l e n e s o r b i t a n f a t t y a c i d esteis. Table V reveals that t h i s series of products also shows v a r i a t i o n s b a s e d on t h e p o l y o x y e t h y l e n e c h a i n length. TABLE V Fatty Acid Esters Sample AOCS Smoke P o i n t HLB 13.3 265 POE s o r b i t a n monolaurate 16.7 327 POE s o r b i t a n monolaurate

8

POE

fil

POE POE POE POE POE POE

m

C203 m

s o r b i t a n monopalmitat s o r b i t a n mono stearate s o r b i t a n monostearate sorbitan tristearate s o r b i t a n monooleate s o r b i t a n monooleate sorbitan trioleate

230

9.6

330 255 264 366 229

14.9

10.5 lO.O

15.0

11.0

The o b v i o u s r e l a t i o n s h i p between f u m i n g p r o p e r t i e s and e t h y l e n e o x i d e c o n t e n t a r e a g a i n apparent with the polyoxyethylene s o r b i t a n f a t t y a c i d e s t e r s . T h e s e p r o d u c t s a r e b i o d e g r a d a b l e and o f f e r v e r s a t i l i t y i n a wide range of e m u l s i f i c a t i o n areas. The v a r i a t i o n i n e m u l s i f i c a t i o n p r o p e r t i e s with chemical type, o r more s p e c i f i c a l l y t h e f a t t y a c i d u s e d , a l l o w s t h e f o r m u l a t o r t o g r e a t l y improve emulsion stability through o p t i m i z a t i o n of chemical type. The t h i r d and f i n a l c l a s s i f i c a t i o n o f c h e m i c a l s t o be i n t r o d u c e d as e m u l s i f i e r s a r e t h e p o l y o x y e t h y l ene e t h e r s o f a l c o h o l s ( T a b l e V I ) . As w i t h t h e o t h e r compounds h a v i n g a p o l y o x y e t h y l e n e c h a i n l e n g t h , t h e s e p r o d u c t s a l s o show f u m i n g p r o p e r t i e s c o r r e l a t i n g t o the ethylene oxide chain length. Another notable f e a t u r e o f the polyoxyethylene e t h e r s i s the good l u b r i c a n t p r o p e r t i e s , c o u p l e d w i t h adequate e m u l s i f i c a t i o n p r o p e r t i e s i n a wide range o f a r e a s , and t h i s s u g g e s t s u s e o f t h e s e p r o d u c t s i n a p p l i c a t i o n s w h e r e low f r i c t i o n a l p r o p e r t i e s a r e d e sired. This series of products are biodegradable. The a r e a p r e s e n t i n g t h e g r e a t e s t p r o b l e m t o t h e f o r m u l a t o r o f nonfuming f i n i s h e s i s the s e l e c t i o n o f

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160

POE POE POE POE POE POE POE POE POE POE POE

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

M M M m β

TABLE VI Polyoxyethylene Ethers Product HLB Smoke P o i n t lauryl ether 9.7 185 l a u r y l ether 16.9 345 cetyl ether 5.3 185 c e t y l ether 12.9 258 c e t y l ether 15.7 306 s t e a r y l ether 4.9 203 s t e a r y l ether 12.4 284 s t e a r y l ether 15.3 300 o l e y l ether 4.9 193 o l e y l ethe o l e y l ethe

M

proper a n t i s t a t i c agents. B a s i c a l l y , a n t i s t a t s work v i a e i t h e r o f two r o u t e s . Most i o n i c t y p e s d i s s i p a t e t h e s t a t i c c h a r g e , w h i l e m o i s t u r e i s r e t a i n e d by most nonionic agents, although there are exceptions to that method o f c l a s s i f i c a t i o n . The most e f f e c t i v e a n t i ­ s t a t s a r e n o r m a l l y f o u n d among t h e two i o n i c t y p e s , b u t many o f t h e s e c o m p o u n d s p r e s e n t f u m i n g problems. Some n o t a b l e e x c e p t i o n s may b e f o u n d w i t h t h e h e t e r o ­ c y c l i c amine q u a t e r n a r i e s w i t h d i e t h y l or d i m e t h y l s u l f a t e w h i c h h a v e smoke p o i n t s a b o v e 3 2 0 ° F . Another c l a s s i s the polyoxyethylene d i e t h y l s u l f a t e quater­ nary f a t t y amines. W h i l e not as e f f e c t i v e on a w e i g h t b a s i s , a w i d e r s e l e c t i o n o f nonfuming components i s f o u n d w i t h noni o n i c a n t i s t a t i c components. Many o f t h e c o m p o n e n t s a l r e a d y d i s c u s s e d such as the s e r i e s o f polyoxyethy1«B s o r b i t a n f a t t y a c i d e s t e r s , or the polyoxyethylene fatty acid esters w i l l offer a reasonable level of static protection. Thus t h e use o f t h e s e components a s e m u l s i f i e r s a n d / o r l u b r i c a n t s may e l i m i n a t e o r r e d u c e t h e amount o f a d d i t i o n a l a n t i s t a t r e q u i r e d . P e r h a p s a more w i d e l y a c c e p t e d c l a s s o f n o n i o n i c a n t i s t a t s would be the p o l y o x y e t h y l e n e f a t t y amines. Many p r o d u c t s i n t h i s c a t e g o r y m e e t t h e smoke p o i n t c r i t e r i a , e s p e c i a l l y t h o s e i n t h e r a n g e o f 12-20 m o l e s of ethylene oxide. We h a v e now d i s c u s s e d a l l o f t h e m a j o r c o m p o n e n t s necessary i n the d e s i g n o f a "nonfuming f i n i s h " . The s e l e c t i o n o f components w i l l depend on t h e f i n a l p r o p ­ e r t i e s one i s a t t e m p t i n g t o a c h i e v e as w e l l a s any

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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161

other

e c o l o g i c a l or a s t h e t i c r e q u i r e m e n t s t o be met. T h e r e a r e many o t h e r t e s t s t h a t may a n d should be u s e d d u r i n g p r e s c r e e n i n g o f nonfuming s p i n f i n i s h systems. Two o f t h e m o r e commonly u s e d a r e : F u m i n g T e s t -- U s u a l l y 15 m i n u t e s a t 2 6 5 ° C u s i n g a 5 gram specimen. 10% o r l e s s f i n i s h l o s s w i t h a minimum o f c o l o r d e g r a d a t i o n i s desirable. Varnish or Residue — N o r m a l l y 16-24 hours u s i n g a 1 gram s p e c i m e n . Maximum o f 10% remaining residue i s d e s i r a b l e . W h i l e l a b o r a t o r y t e s t i n g i s o f extreme importance, we must k e e p i n m i n the f i n i s h runs i n process yarn without difficulty. I n summary, we h a v e d i s c u s s e d a l a r g e number o f chemicals u s e f u l i n the f o r m u l a t i o n o f nonfuming s p i n f i n i s h systems. By p r o p e r s e l e c t i o n , i t i s p o s s i b l e t o a c h i e v e many v a r i e d f i n i s h p r o p e r t i e s a n d design s y s t e m s m e e t i n g OSHA r e q u i r e m e n t s i n t e r m s o f f u m i n g while achieving f i n i s h p r o p e r t i e s s i m i l a r to those of more t r a d i t i o n a l l y u s e d components.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

10 Reactions of a Difluorochloropyrimidine Dyestuff with Wool Peptide Models ULRICH ALTENHOFEN (1) and HELMUT ZAHN Deutsches Wollforschungsinstitut an der Technischen Hochschule Aachen, Bundesrepublik Deutschland

1. The present stat rates i n reactiv W. F . Beech (2) has given a clear account on the mechanism of reaction of proteins with reactive dyes and quotes Shore (3) i n summarizing the position: "It appears that the main groups i n protein fibres which participate i n the reaction with reactive dyes are the primary amino groups of lysine, the N-terminal residues, the imidazole group of histidine, followed by the cysteine thiol group and the tyrosine phenolic group." Beech i s correct i n stating that the distribution of the dye molecules between the different groups w i l l vary for different proteins, for different reactive systems and for different experimental conditions. The behaviour of chloroacetyl, omega-chloroalkylsulfonamide, vinyl sulfone , chlorotriazinyl, chloropyrimidyl dyes as well as of dyes containing acrylamido groups with wool has been studied (2) , (4) . By detailed examination of rate fixation curves, the variation of reactivity of acryloylamino dyes with pH at 100 C was obtained by Derbyshire and ïristram (_5) , while Hildebrand and Meier (6) have investigated the reaction of Verofixorange GL, a difluorochloropyrimidine dyestuff with histidine, thioglycolic acid and glycine at pH 4.5 and 80 C and have presented data for the reaction rates. We were stimulated by this paper as well as by our standing interest i n compounds with two reactive fluorines (T). Dr. Bien from Bayer, Leverkusen synthesized the blue anthraquinone dyestuff (I) according to example 400 of Bayer's patent application (Offenlegungsschrift Nr. 1,644,171) and Dr. Siegel provided us with a sample of this wool blue dyestuff. Dr. Hildebrand (8^) proposed to study not only the site of reaction in wool but also the reaction velocities 162

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

10.

ALTENHOFEN AND ZAHN

Difluorochloropyrimidine Dyestuff

163

i n a more s o p h i s t i c a t e d manner t h a n he r e p o r t e d i n h i s p a p e r q u o t e d a b o v e . We d e c i d e d t o d y e t h e % - a c e t y l m e t h y l a m i d e s o f amino a c i d s as a r e s u l t o f r e s u l t s o b t a i n e d from e a r l i e r experiments w i t h -acetyl-lysinem e t h y l a m i d e (SO The f o l l o w i n g i s a d e s c r i p t i o n o f o u r e x p e r i m e n t s w i t h t h e d y e s t u f f (I) and t h e w o o l p e p t i d e m o d e l s m e n t i o n e d a b o v e . We s u c c e e d e d i n i s o l a t i n g t h e s i n g l e r e a c t i o n p r o d u c t s and in calculating reaction r a t e s f r o m c o l o r i m e t r i c d a t a w i t h t h e a i d o f a FORTRAN computer program. f

2.

Material

and

methods

T h e d y e s t u f f ( I ) was B a y e r AG, L e v e r k u s e n p u r i f i c a t i o n . N^-acetyl-methylamides of l y s i n e , histi­ d i n e and t y r o s i n e were p r e p a r e d a c c o r d i n g t o p u b l i s h e d procedures (9) w i t h some m i n o r m o d i f i c a t i o n s ( 1 0 ) . A c e t y l - c y s t e i n e m e t h y l a m i d e was o b t a i n e d f r o m b i s a c e t y l cystinemethylamide (11)by r e d u c t i o n w i t h z i n c i n a c e t i c a c i d : 0.5 g c y s t i n e d e r i v a t i v e w e r e d i s s o l v e d i n 20 m l a c e t i c a c i d . 0.5 g z i n c were added. A f t e r stirring f o r 3 h o u r s a t room t e m p e r a t u r e the excess of zinc was r e m o v e d b y f i l t r a t i o n a n d t h e f i l t r a t e was evapo­ r a t e d i n v a c u o . The p r o d u c t g a v e a t h i o l c o n t e n t 70-80% o f t h e o r y as determined w i t h E l l m a n ' s r e a g e n t (12). R e a c t i o n s o f d y e s t u f f (I) w i t h t h e w o o l p e p t i d e m o d e l s were c a r r i e d o u t i n a d o u b l e chamber v e s s e l provided with Ingold high temperature e l e c t r o d e s type 202 a n d 262, n i t r o g e n i n l e t , r e f l u x c o n d e n s e r , and t h e r m o m e t e r . pH v a l u e s w e r e k e p t c o n s t a n t b y c o n n e c t i o n w i t h an A u t o t i t r a t o r (Radiometer Copenhagen). A t various t i m e s s a m p l e s 0.5 m l e a c h w e r e w i t h d r a w n k e p t a t 0 ° C a n d 50 j a l 1N h y d r o c h l o r i c a c i d was added. S a m p l e s (10 μ ΐ ) w e r e a p p l i e d t o t h i n l a y e r p l a t e s (F 254, M e r c k , D a r m s t a d t ) w h i c h w e r e d e v e l o p e d w i t h a m i x t u r e o f n - b u t a n o l , e t h a n o l and w a t e r (4:3:3). A f t e r e l u t i o n t o 2 a n d 5 cm, t h e p l a t e s w e r e d r i e d a n d a g a i n c h r o m a t o g r a p h e d i n t h e same s o l v e n t m i x t u r e t o a d i s t a n c e o f a t l e a s t 12-15 cm. T h e p l a t e s w e r e a g a i n d r i e d a n d i m m e d i a t e l y m e a s u r e d i n a Z e i s s PMQ II p l a t e photometer. With the p h o t o c e l l c l o s e d t r a n s ­ m i s s i o n was c a l i b r a t e d a t 0% a n d a t a s u b s t a n c e free s p o t o f t h e t h i n l a y e r p l a t e a t 100%. T h e p l a t e was s c a n n e d i n t h e d i r e c t i o n o f r u n n i n g by a s l i t d i a p h r a g m . T h e p h o t o m e t e r d a t a w e r e e v a l u a t e d b y a FORTRAN computer p r o g r a m on t h e b a s i s o f an e m p i r i c a l c a l i b r a t i o n function.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

164

3.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

The v a r i o u s p o s s i b i l i t i e s f o r f u n c t i o n a l g r o u p s and w a t e r

reaction

of

(I)

with

Fig. 1 shows some o f t h e p o s s i b l e r e a c t i o n s i n a q u e o u s s o l u t i o n s of the difluorochloropyrimidine dyestuff (I) with four w o o l p e p t i d e m o d e l s (R-H) containing the f u n c t i o n a l side chain groups of l y s i n e , c y s t e i n e , h i s t i d i n e and t h e f u n c t i o n a l m a i n c h a i n g r o u p o f N - t e r m i n a l g l y c i n e . The f i r s t r e a c t i o n shows t h e s u b s t i t u t i o n r e a c t i o n on t h e f i r s t f l u o r i n e , t h e s e c o n d r e a c t i o n t h e s u b s t i t u t i o n o f t h e m o n o s u b s t i t u t e d product w i t h a f u r t h e r w o o l p e p t i d e m o d e l . The l a s t r e a c t i o n r e p r e s e n t s t h e h y d r o l y s i s o f t h e f i r s t f l u o r i n e , leading to a monohydroxylderivative of d y e s t u f f (I) By titra t i o n of the h y d r o g e n f l u o r i d reactions depicted i c a n be m e a s u r e d . T h i s was d o n e b y o n e o f u s (1_0) a n d has p r o v i d e d v e r y u s e f u l d a t a on t h e r e a c t i v i t i e s o f the f u n c t i o n a l g r o u p s a t pH v a l u e s 4.5 - 8.5 a t various t e m p e r a t u r e s as w e l l as on t h e d y e s t u f f hydrolysis. These d a t a s e r v e d as e s s e n t i a l f a c t s f o r planning t h e experiments described i n t h i s communication. In o r d e r t o study the t h r e e r e a c t i o n s o u t l i n e d i n f i g . 1 separat e l y , t h e mono-and d i s u b s t i t u t e d a n d t h e h y d r o l y s e d p r o d u c t s were s e p a r a t e d by t h i n l a y e r c h r o m a t o g r a p h y f o l l o w i n g p r o c e d u r e s a l r e a d y d e s c r i b e d by M â u s e z a h l (13) a n d G. R e i n e r t (14). We h a v e f o u n d t h a t t h e p h o t o m e t r i c a s s e s s m e n t o f our èilica g e l t h i n l a y e r p l a t e s by c o m b i n a t i o n o f r e m i s s i o n and t r a n s m i s s i o n m e a s u r e m e n t c a n be i m p r o v e d i f a white paper i s put under the t h i n l a y e r p l a t e (see f i g . 2 ) . Fig. 3 shows a n e x a m p l e o f t h e d a t a o b t a i n e d b y the photometric assessment of dyestuff-derivatives s e p a r a t e d on t h i n l a y e r p l a t e s f o r t h e r e a c t i o n o f dyestuff (I) w i t h g l y c i n e m e t h y l a m i d e a t 8 0 ° C a n d pH 5. O n l y mono- a n d d i s u b s t i t u t e d r e a c t i o n p r o d u c t s w e r e f o u n d a n d i d e n t i f i e d - The b i f u n c t i o n a l r e a c t i o n o f (I) i s v e r y s l o w . D y e s t u f f h y d r o l y s i s c a n be n e g l e c t e d . I n t h i s s i m p l e c a s e t i t r a t i o n o f HF f o r m e d c a n b e u s e d to c a l c u l a t e approximate values f o r the reaction v e l o c i t y k.. We f o u n d 0.262 1 / m o l . m i n . L a t e r , a v a l u e o f 0.226 1 / m o l . m i n was c a l c u l a t e d o n t h e b a s i s o f the s e p a r a t e d m o n o s u b s t i t u t e d dye derivative.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

ALTENHOFEN AND ZAHN

165

Difluorochloropyrimidine Dyestuff

Dyestuff (I), German Offenlegungschrift 1,644,171; example 400

Cl

R

.

H +

F

Cl

(D)^ ^(D>^ R

F

Cl

Cl

2

+

Cl

F

2

C h 2

"

+ f

HF

CI

R= -NH-(CH)X

^Tjf

R

(BK_^

H 0 (D>y^

+ HF

N

-S-C^-X

r

X

-

N H

-

C H

2 CO-NH-CH3

X= CH3-CO-NH-CH-CO-NH-CH3

Figure 1. Mono- and disubstitution of the dyestuff (I) by peptide models and hydrolysis of(l)

photocell amplifier

è

Λ-

monochromator

DC-plate

/ W-lamp

recorder w h i t e background Figure

2.

Scheme showing

the photometric assessment of thin hyer with the Zeiss PMQII

plates

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

166

4.

C a l c u l a t i o n of

reaction

rates

The s u b s t a n c e w i t h i n a s p o t i n t h e t h i n l a y e r c h r o m a t o g r a m s h o w s a n o r m a l d i s t r i b u t i o n ( 1J5) . C o n s t a n t s p o t widths a l l o w t h e m a t h e m a t i c a l d e s c r i p t i o n o f a s p o t by p e a k h e i g h t a n d p e a k w i d t h a t h a l f h e i g h t . I t was found t h a t t h e l o g a r i t h m o f t h e amount o f t h e d y e s t u f f d e r i ­ v a t i v e i n a spot i s not l i n e a r l y r e l a t e d t o the values o f h e i g h t and w i d t h even a f t e r l o g a r i t h m i z a t i o n . One m u s t a d d t h e q u a d r a t i c t e r m s . We c a n n o t d e a l w i t h t h e d e t a i l e d d e s c r i p t i o n of the mathematics a p p l i e d w i t h i n t h i s c o m m u n i c a t i o n b u t i t c a n be f o u n d i n t h e t h e s i s o f o n e o f u s (J_) . The f i n a l f o r m u l a f o r t h e c a l c u l a t i o n o f amounts o f d y e s t u f f d e r i v a t i v e contained a s 6 t e r m s a n d was applie t h i n l a y e r spots containin p e r s p o t . The e v a l u a t i o n h a d t o b e d o n e b y m e a n s o f a computer program. C o l o u r e d s u b s t a n c e s s u c h as the d y e s t u f f itself, i t s r e a c t i o n p r o d u c t s w i t h t h e p e p t i d e m o d e l s as w e l l a s h y d r o l y s e d d y e c a n now b e a s s e s s e d q u a n t i t a t i v e l y a f t e r having e s t a b l i s h e d the c a l i b r a t i o n curve f o r the d y e s t u f f . The r e a c t i o n m i x t u r e c a n b e e x p r e s s e d a s follows : F where F F^ M

=

F, + Μ. + t t

Β, + t

= m o l a r amount = m o l a r amount = m o l a r amount time t = m o l a r amount time t = m o l a r amount

Q

t

B

ο

t

H, t

of d y e s t u f f at the start of dyestuff at time t of monosubstituted dyestuff

at

of

disubstituted dyestuff

at

of

hydrolysed

timet

dyestuff

at

The p e p t i d e m o d e l s a r e c o l o u r l e s s a n d t h e r e f o r e c a n n o t be e s t i m a t e d by c o l o r i m e t r y o f t h e s p o t s on t h e t h i n l a y e r c h r o m a t o g r a m s . The c o n c e n t r a t i o n o f t h e peptide m o d e l h o w e v e r was c a l c u l a t e d f r o m t h e f o l l o w i n g equation: P

P P

t

Q

t

-

P

o

-

= molar = molar

M

t

-

2

'

B

t

amount o f amount o f

peptide peptide

model a t model a t

time t the s t a r t

In order t o c a l c u l a t e the c o n c e n t r a t i o n of d y e s t u f f a n d i t s d e r i v a t i v e s a l l v a l u e s h a d t o be d i v i d e d b y s a m p l e v o l u m e s . The f o l l o w i n g k i n e t i c e q u a t i o n s were u s e d :

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

the

10. ALTENHOFEN AND ZAHN

Hydrolysis:

d

t

^

Monosub-

Difluorochloropyrimidine Dyestuff

)

= k

. F(t)

3

/mm

^ .P Ct) ·Ρ Ct)-k «MCt) ·Ρ Ct)

=

stitution: Consumption o f the peptide model:

167

2

, , ,> p

at

.F ( t ) .P ( t ) - k

2

.M

CtKP Ct)

S i m u l t a n e o u s and c o n s e c u t i v e r e a c t i o n s o f t h i s k i n d h a v e n o t b e e n d e s c r i b e d i n l i t e r a t u r e (V5) · T h e a b o v e e q u a t i o n s w e r e t r a n s f o r m e d i n o r d e r t o make i n t e g r a t i o n possible. Reaction rate of h y d r o l y s i s :

^ _ 3

H(t) t J

F( ).dr T

τ =o Reaction rate of monosubstitution:

C*>+M(t)

P

V 1

t Γ

F (τ) .Ρ (τ) .dT

Τ =ο Reaction rate of the second substitution:

P -P(t)-M(t) Q

k = 2

, Τ

, _, . M ( r ) -Ρ (τ) -dT λ

=o

The e q u a t i o n s were s o l v e d u s i n g t h e c u r r e n t methods o f numerical mathematics such as t r a p e z o i d formula, S i m p s o n s s f o r m u l a and a polynom a p p r o x i m a t i o n , t h e l a t t e r o f f e r s t h e a d v a n t a g e t h a t random e r r o r s o f measurement c a n b e c o m p e n s a t e d . F i g . 4 g i v e s a n e x a m p l e o f t h e k i n d o f r e s u l t s w h i c h were o b t a i n e d u s i n g t h e e q u a t i o n f o r t h e c a l c u l a t i o n o f t h e r e a c t i o n r a t e k^ f o r m o n o s u b s t i t u t i o n o f d y e s t u f f by a c e t y l - c y s t e i n e m e t h y l a m i d e a t pH v a l u e s b e t w e e n 4.5 a n d 6 a t t e m p e r a ­ t u r e s b e t w e e n 8 0 ° C a n d 95 C. 1

F i g . 5 shows t h e r e s u l t s f o r t h e r e a c t i o n o f d y e s t u f f (I) w i t h N ^ - a c e t y l - l y s i n e - m e t h y l a m i d e . I t c a n be s e e n t h a t t h e r e a c t i o n r a t e s d i f f e r n o t o n l y i f c o m p a r e d a t t h e same pH b u t a l s o i n t h e i r p H - d e p e n d e n c e , T h e n e x t c h a p t e r w i l l show how a b s o l u t e reactivities o f wool p e p t i d e models c a n be obtained.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

168

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

concentration μ mol/1

dye

monosubstituted I disubstituted / reaction-product '\, H y d r o l y s a t

100 Figure

3.

Reaction

200

300

time min

of dyestuff (I) with glycine-methylamide pH 5

at

80°C,

Figures 4 and 5. Reaction of dyestuff (I) with N-acetyl-cysteine-methyhmide (left) and Ν oc -acetylr-lysine-methyhmide (right). Variation in velocities of the monosubstitution reaction with pH and temperature.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

10.

ALTENHOFEN AND ZAHN

5.

pH-Dependence

of

Difluorochloropyrimidine Dyestuff

169

reaction velocities

I t i s known t h a t a m i n o g r o u p s i n p r o t e i n s , p e p t i d e s o r amino a c i d s do r e a c t by s u b s t i t u t i o n o r a d d i t i o n i n t h e i r unprotonated n u c l e o p h i l i c f o r m ( V7) , (1_8) . I n t h e case of our r e a c t i o n w i t h d y e s t u f f ( I ) (F-D) the following e q u a t i o n s h o l d true:

">NH R

+

F-D

)>N-D R

1

+

HF

1

k ^ i s the r a t e constant form o f the amino a c i d R(R')NH c a n be d e r i v e where the d i s s o c i a t i o

f o r the r e a c t i o n of d i s s o c i a t e d Therefor th concentratio f

+ R'

R'

2

Lindley (18) f i r s t c a l c u l a t e d l i n e a r r e g r e s s i o n e q u a t i o n s d e s c r i b i n g the r e l a t i o n between r e a c t i o n r a t e s a n d p H - v a l u e s . H i s m e t h o d was the b a s i s f o r our FORTRAN p r o g r a m a n d p r o v i d e d t h e pH i n d e p e n d e n t r a t e c o n s t a n t s k.. In a d d i t i o n the d i s s o c i a t i o n c o n s t a n t s Κ w e r e c a l c u l a t e d . We c a n n o t d e a l i n t h i s c o m m u n i c a t i o n u s e d and r e f e r t o t h e f o r m u l a o f G o r i n , M a r t i n and D o u g h t y (20) w h i c h was used f o r e v a l u a t i n g reactions o f t h i o l compounds. p K - v a l u e s o f o u r p e p t i d e m o d e l s were, i n a d d i t i o n , d i r e c t l y m e a s u r e d by potentiometric t i t r a t i o n up t o t e m p e r a t u r e s o f 95 C. D y e i n g i s n o r m a l l y e f f e c t e d a t 100°C b u t p o t e n t i o m e t r i c measure­ ments a t t h i s t e m p e r a t u r e were not p o s s i b l e . The p K - v a l u e s were t h e r e f o r e o b t a i n e d by extrapolation. F i g . 6 shows t h e t e m p e r a t u r e d e p e n d e n c e o f p K - v a l u e s f o r the f i v e p e p t i d e models s t u d i e d . From t h e s e p l o t s d i s s o c i a t i o n e n t h a l p i e s were c a l c u l a t e d . V a l u e s a r e g i v e n i n J / m o l i n t h e l e g e n d o f f i g . 6. F i g . 6 shows c l e a r l y t h e i n f l u e n c e o f t h e e n t h a l p y o f d i s s o c i a t i o n . Whereas t h e v a l u e s f o r t h e β - a m i n o group of the l y s i n e d e r i v a t i v e , f o r the imidazole of t h e h i s t i d i n e d e r i v a t i v e as w e l l as f o r t h e amino group of g l y c i n e methylamide are c l o s e l y r e l a t e d , the enthalpy of d i s s o c i a t i o n f o r the phenolic hydroxyl group of the t y r o s i n e d e r i v a t i v e i s only about h a l f . T h i s means t h a t i n c r e a s e d t e m p e r a t u r e s f a v o u r t h e d i s s o c i a t i o n o f t h e p r o t o n a t e d amino g r o u p s more t h a n

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

170

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

that of the p h e n o l i c hydroxyl. This c l e a r l y e x p l a i n s an e a r l i e r o b s e r v a t i o n (K>) n a m e l y t h a t t h e t y r o s i n e p e p t i d e model r e a c t s w i t h d y e s t u f f (I) w i t h n o r m a l r a t e s at a l k a l i n e pH-values only. T h e e s t i m a t i o n o f p K - v a l u e s b y t i t r a t i o n was not p o s s i b l e w i t h the c y s t e i n e d e r i v a t i v e because t h i o l a t e anions are extremely s e n s i t i v e to o x i d a t i o n at higher t e m p e r a t u r e s . H e n c e we h a d t o c a l c u l a t e t h e p K - v a l u e s from the r e a c t i o n r a t e s a t higher temperatures. The most s i g n i f i c a n t r e s u l t s o f t h e s e c a l c u l a t i o n s a r e t h e v e r y s m a l l r e a c t i o n r a t e s o f t h e SH f o r m o f t h e c y s t e i n e d e r i v a t i v e . We t h e r e f o r e b e l i e v e t h a t o n l y the t h i o l a t e a n i o n -S° i s a b l e t o r e a c t w i t h the dyestuff (I). 6.

Nucleophilicity o

group

peptid

I f one p l o t s t h e r e a c t i o n r a t e s o f t h e p e p t i d e m o d e l s i n t h e i r r e a c t i v e d i s s o c i a t e d form a g a i n s t the pKvalues,curves s u c h as t h o s e i n f i g . 7 a r e o b t a i n e d . It c a n be s e e n t h a t t h e pH i n d e p e n d e n t r e a c t i o n r a t e i n c r e a s e s w i t h t h e p K - v a l u e . P e p t i d e m o d e l s whose f u n c t i o n a l g r o u p i s a n a m i n o o r i m i n o g r o u p show a l i n e a r f u n c t i o n i n the logarithmic s c a l e , whereas the c y s t e i n e d e r i v a t i v e shows a n h i g h e r r e a c t i v i t y t h a n p r e d i c t e d on t h e b a s i s o f t h e p K - v a l u e . T h i s c o r r e s p o n d s t o t h e known g r e a t e r n u c l e o p h i l i c i t y o f -S g r o u p s compared t o t h a t o f amino g r o u p s . 7.

Reaction

rates

at

d i f f e r e n t temperatures

F i g . 8 shows a n A r r h e n i u s p l o t o f t h e i n f l u e n c e o f t e m p e r a t u r e on t h e r a t e o f s u b s t i t u t i o n o f t h e first f l u o r i n e b y v a r i o u s p e p t i d e m o d e l s a t pH 5. I t c a n be s e e n t h a t t h e s l o p e a n d h e n c e t h e e n e r g i e s of a c t i v a t i o n do n o t d i f f e r g r e a t l y b e t w e e n t h e peptide m o d e l s s t u d i e d . The r e a c t i o n r a t e s a t t h e d y e i n g t e m p e r a t u r e o f 100 C w e r e o b t a i n e d b y e x t r a p o l a t i o n a n d a r e g i v e n i n t a b l e 1. Table

1:

Reaction polation

Peptide

r a t e s a t 100°C o b t a i n e d by of the curves i n f i g . 8

model

Ac-Lys-NH-Me Gly-NH-Me Ac-His-NH-Me Ac-Cys-NH-Me

Reaction rate at 1/mol.min

extra-

100°C

0.4 1.1 1 .2 2.1

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

10.

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Difluorochloropyrimidine

Dyestuff

171

Ac-Lys-NH-Me 10 Ac-Tyr-NH-Me

9i 8

Gly-NH-Me

76"

Ac-His-NH-Me

5 VT-10 2,7

2,8 1

«-|

2,9 1

3,0

1

100 90 80 70

3,1

1

1

60

50

KL 1000 l/molmin

3,2 1

3,3 —I

4

Κ

°c

3

Figure 6. Temperature dependence of pK values of peptide models. En­ thalpy values of dissociation in paren­ theses in J/mol. Ac-Lys-NH-Me (54.8 ± 15.6) Ac-Tyr-NH-Me (25.6 ± 8.5), Gly-NH-Me (52.7 ± 13.6)

/Ac-Lys-NH-Me

100J

10-

Ac-Cys-NH-Me 'Gly-NH-Me

U

Ac-His-NH-Me

^

.

.

Γ

pK

Figure 7. pH independent rates vs. pK values based on ments at 80°C

reaction measure­

l/mol - min 2,0 1,0

0,5

-NH-Me 0,1

0,05 »—u-,— 80

85

90

95 100 Temperature (°C)

Figure 8. Arrhenius plot of the rate of reactions of four peptide models with dyestuff (I) at pH 5.0

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

172

8.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

Reactions

of

the

second

fluorine

of

dyestuff

(I)

We i n v e s t i g a t e d t h e pH d e p e n d e n c e o f t h e s e c o n d substit u t i o n r e a c t i o n i n t h e same m a n n e r a s i t h a s b e e n d o n e f o r t h e f i r s t s u b s t i t u t i o n . The e x p e r i m e n t a l e r r o r s h o w e v e r w e r e g r e a t e r b e c a u s e we t e r m i n a t e d t h e r e a c t i o n s a t t i m e s where t h e amount of t h e b i f u n c t i o n a l r e a c t i o n p r o d u c t was r e l a t i v e l y s m a l l . F o r t h i s we h a v e n o t p r o v i d e d v a l u e s f o r t h e r a t i o ^ / ^ - i · We w i l l s i m p l y s t a t e t h a t the second r e a c t i o n o c c u r s a t approximately t h e same r a t e a s t h e f i r s t s u b s t i t u t i o n i n t h e c a s e o f t h e l y s i n e p e p t i d e m o d e l . The s e c o n d s u b s t i t u t i o n o f t h e d e r i v a t i v e s o f c y s t e i n e , h i s t i d i n e and g l y c i n e on t h e o t h e r h a n d , see 9.

Hydrolysis of dyestuff

(I)

I t c a n b e s e e n f r o m f i g . 1 t h a t n o t o n l y mono- a n d d i s u b s t i t u t e d r e a c t i o n products but a l s o hydrolysed d y e s t u f f i s f o r m e d i f (I) i s r e a c t e d w i t h p e p t i d e m o d e l s . I n v i e w o f t h e f a c t t h a t t h e amounts formed were v e r y s m a l l , t h e h y d r o l y s i s r a t e cannot be m e a s u r e d v e r y a c c u r a t e l y . The o n l y p o i n t o f i n t e r e s t here i s the f a c t t h a t the h y d r o l y s i s i s s i g n i f i c a n t l y g r e a t e r i f the d y e s t u f f i s r e a c t e d with the h i s t i d i n e d e r i v a t i v e a t 95 C a n d pH 5.6. 10.

Conclusions

Evidence i s presented that a d e t a i l e d k i n e t i c analysis of c o m p l i c a t e d s i m u l t a n e o u s and c o n s e c u t i v e r e a c t i o n s s u c h as r e a c t i o n s o f v a r i o u s p e p t i d e models and w a t e r w i t h a b i f u n c t i o n a l compound c a n be e x e c u t e d . The s i n g l e steps of the procedure are: s e p a r a t i o n of the c o l o u r e d s p o t s by t h i n l a y e r c h r o m a t o g r a p h y , s c a n n i n g p h o t o m e t r y , and n u m e r i c a l e v a l u a t i o n o f t h e p h o t o m e t e r d a t a b y a FORTRAN c o m p u t e r p r o g r a m b a s e d o n a n e m p i r i c a l c a l i b r a t i o n f u n c t i o n . The k i n e t i c d a t a p r e s e n t e d d i f f e r g r e a t l y from p u b l i s h e d data f o r r e a c t i o n s of s i m i l a r d y e s t u f f s w i t h wool o r amino a c i d s (6). N e v e r t h e l e s s one c a n n o t d i s c u s s p o s s i b l e e x p l a n a t i o n s c o n s i d e r i n g the f a c t t h a t experimental c o n d i t i o n s such a s pH , t e m p e r a t u r e a n d r e a c t a n t s c a n n o t b e c o m p a r e d . E x p e r i m e n t a l e r r o r s c a n n o t be e x c l u d e d f r o m t h e p r e s e n t work and o n l y t h r o u g h f u r t h e r p r o g r e s s i n t h i s field t h e s e d a t a c a n be v e r i f i e d . I n any c a s e one c a n conclude t h a t the d i f l u o r o c h l o r o p y r i m i d i n e d y e s t u f f r e a c t s under m i l d l y a c i d i c d y e i n g c o n d i t i o n s a t 80 - 95 C w i t h t h e amino and i m i n o g r o u p s o f l y s i n e and h i s t i d i n e and t h e group o f c y s t e i n e p r e d o m i n a n t l y w h e r e a s t h e r e a c t i o n s

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

ALTENHOFEN AND ZAHN

10.

Difluorochloropyrimidine Dyestuff

173

w i t h the p h e n o l i c hydroxy1 groups of t y r o s i n e can be n e g l e c t e ^ u n d e r t h e c o n d i t i o n s c h o s e n . The f a c t t h a t Verofix dyes r e a c t w i t h w o o l f r o m a c i d i c dye bath l i q u o r s (6) c a n now b e e x p l a i n e d b y o u r f i n d i n g t h a t the d i s s o c i a t i o n constant of the protonated amino g r o u p o f l y s i n e i n c r e a s e s u n e x p e c t e d l y r a p i d l y as t h e temper a t u r e a p p r o a c h e s 1 0 0 ° C . To o u r k n o w l e d g e n o d a t a on p K - v a l u e s o f f u n c t i o n a l g r o u p s o f p r o t e i n s n e a r 100 C h a v e b e e n p u b l i s h e d . The t w o f o l d e s t i m a t i o n o f pKv a l u e s a t d i f f e r e n t t e m p e r a t u r e s , o n e by evaluation o f t h e pH-dependence o f r e a c t i o n r a t e s , and t h e other by d i r e c t t i t r a t i o n o f t h e p e p t i d e f u n c t i o n a l g r o u p s seems t o be a s o u n d b a s i s f o r f u r t h e r r e f i n e m e n t and a p p l i c a t i o n i n othe field f protei chemistry We a r e u n c e r t a i s e c o n d s u b s t i t u t i o n and t h e h y d r o l y s i s a r e c o n c e r n e d . How c a n one u n d e r s t a n d t h e f a s t s e c o n d r e a c t i o n o f t h e £-amino g r o u p o f l y s i n e and t h e s l o w r e a c t i o n o f t h e cG-amino g r o u p o f g l y c i n e ? S t e r i c r e a s o n s o f f e r no e x p l a n a t i o n . F u r t h e r work i s needed t o c l e a r t h i s p o i n t , The i n c r e a s e d r a t e o f d y e s t u f f h y d r o l y s i s d u r i n g the r e a c t i o n w i t h the h i s t i d i n e p e p t i d e model i s not u n e x p e c t e d i f one c o n s i d e r s t h e c a t a l y t i c r o l e o f t h e i m i d a z o l e m o i e t y (2Y) . One s h o u l d c a r r y o u t more experiments on t h e p o s s i b l e r o l e o f d y e b a t h c o n s t i t u e n t s o n t h e h y d r o l y s i s o f r e a c t i v e d y e s . The m e t h o d p r e s e n t e d i n t h i s s h o r t c o m m u n i c a t i o n c a n be a p p l i e d f o r comparing v a r i o u s r e a c t i v e d y e s t u f f systems i n t h e i r r e a c t i v i t y t o w a r d s t h e more i m p o r t a n t f u n c t i o n a l g r o u p s i n f i b r o u s p r o t e i n s . A l t e n h o f e n e t a l . (22) h a v e a l r e a d y compared the r e a c t i v i t i e s o f a v i n y l s u l f o n e dye w i t h t h e d i f l u o r o c h l o r o p y r i m i d i n e dye o f t h e p r e s e n t i n v e s t i g a t i o n . A l t h o u g h many p a p e r s h a v e b e e n p u b l i s h e d f r o m o u r own l a b o r a t o r y on r e a c t i o n s o f 1 . 5 - d i f l u o r o - 2 . 4 - d i n i t r o b e n z e n e {23) and p . p - d i f l u o r o m.m -dinitrodiphenylsulfon (24) w i t h amino g r o u p s and p r o t e i n s , t h e m a i n e m p h a s i s was the s e p a r a t i o n of b r i d g e d amino a c i d s and t h e i r i s o l a t i o n . K i n e t i c d a t a a r e m i s s i n g . I t w o u l d be w o r t h w i l e t o a p p l y t h e t h i n l a y e r chromatography-, scanning-and computerizing t e c h n i q u e d e s c r i b e d t o s o l v e some o f t h e u n a n s w e r e d kinetic questions. 1

1

Acknowledgements T h a n k s a r e due t o Dr. S i e g e l and Dr. B i e n ( Bayer AG) f o r p r o v i d i n g us w i t h s a m p l e s o f r e a c t i v e d y e s t u f f s . We a r e i n d e b t e d t o t h e R e c h e n z e n t r u m o f T e c h n i s c h e Hochschule Aachen f o r h e l p d u r i n g the working out of FORTRAN c o m p u t e r p r o g r a m s a n d e v a l u a t i n g t h e data.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

174

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

Abstract The N^-acetyl-methylamides of cysteine, h i s t i d i n e , l y s i n e tyrosine as well as glycine-methylamide were reacted as peptide models with the d i f l u o r o c h l o r o ­ pyrimidine dyestuff (I) at pH 5 to 9 at temperatures between 80 C and 95 C. E i t h e r one or both f l u o r i n e s of (I) were replaced by the amino-, hydroxy- or t h i o l groups of the peptide models (as well as by hydroxylic groups through h y d r o l y s i s ) . The amino acid d e r i v a t i v e s of (I) and the hydrolysed product of (I) were separated by t h i n layer chromatography and assessed by photo­ metry. Average reactio the f i r s t and secon hydrolysis have been calculated from the c o l o r i m e t r i c data by a computer program. Literature cited 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Altenhofen,U.; Thesis Technische Hochschule Aachen 1975 Beech,W.F.; "Fibre-Reactive Dyes", Logos Press London 1970 S h o r e , J . ; J.Soc.Dyers Colour. (1968) ,84,408 Hildebrand,D.; "The Chemistry of Synthetic Dyes" V o l . V I , ed. by K. Venkataraman, Academic Press, New York and London (1972) p. 327 D e r b y s h i r e , A . N . ; T r i s t r a m , G . R . ; J.Soc.Dyers Colour. (1965) ,81,584 Hildebrand,D.; M e i e r , G . ; T e x t i l - P r a x i s (1971) ,26,499 557 Zahn,H.; Angew. Chem. (1955) ,67,561 Hildebrand,D., p r i v a t e discussion 3.5. 1972 Zahn,H.; M e l l a , K . ; Hoppe-Seyler's Ζ. P h y s i o l . Chem. (1966) ,344, 75 Altenhofen,U.; Diploma t h e s i s , Fachabteilung f ü r Chemie und Biologie der. Technischen Hochschule Aachen, 1972 Zahn,H.; Sroka,W.; Monatsh. Chemie (1967) ,98,745 Meichelbeck,H.; Hack,A.G.; S e n t l e r , C h r . ; Z.ges. T e x t i l i n d . , (1968) ,70, 242 Mäusezahl,D.; Textilveredlung (1970) , 5 , 839 Zahn,H.; R e i n e r t , G . ; K o l l o i d - Z . (1968) ,226, 141 S t a h l , E . ; "Dünnschichtchromatographie, e i n Laboratoriumsbuch" 1. Auflage, Springer V e r l a g , H e i d e l berg 1962 F r o s t , A . A . ; Pearson,R.; "Kinetics and Mechanism" 2 e d i t i o n , John Wiley & Sons, I n c . , New YorkLondon 1961 nd

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

10.

ALTENHOFEN AND ZAHN

Difluorochloropyrimidine

Dyestuff

175

17. Kemp,D.S.; Bernstein,W.; McNeil,G.N.; J. Org. Chem. (1974) ,39, 2831 18. Leon,N.H.; Textile Progress (1975) ,7, 1 19. Lindley,H.; Biochem. J . (1960) ,74, 577 Lindley,H.; Biochem. J . (1962) ,82, 418 Voigt,R.;Wenck,H.;Scheider,F.;Z. Naturf. (1971) ,26b, 1010 20. Gorin,G.; Martic,P.A.; Doughty,G.; Arch. Biochem. Biophys. (1966) ,115, 593 21. Overberger,C.G.; Chah-Moh Shen; J.Am. Chem. Soc. (1971) ,93, 6992 22. Altenhofen,U.;Baumann,H.;Zahn,H.; Proc. 5. Internat. Wool Textile Res. Conf. Aachen (1975), Vol III,529 23. Zahn,H.; Siepmann,E.; Kolloid. Z. & Z. Polymere (1972) ,250, 849 24. Zahn,H.; Hammoudeh,M.M. (1973) ,252, 289

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

11 Shrink-Resist Polymers for Wool: A Comparative Study of Reactive Poly(Alkylene Oxides) for Pad Application DAVID J. KILPATRICK, JOHN A. RIPPON, MICHAEL A. RUSHFORTH, and TREVOR SHAW IWS Technical Centre, Valley Drive, Ilkley, West Yorkshire, LS29 8PB, England In recent years th commercial importanc f polyme shrink -resist processes for woo the time of writing, approximately half the world production of SR wool is polymer treated, the remainder being treated by the older and less effective oxidative processes. Shrink-resist polymers may be applied to wool at any stage of manufacture, from loose stock to garments, but treatment of tops or slivers, fabrics and garments ace of most commercial significance. The polymer treatments which are in industrial use may be divided into two types - those in which prechlorination of the wool is a necessary part of the process (1) and those in which prechlorination is not required (2-7). There are fundamental differences between these two types of process with regard to the polymers used and the mechanism by which shrink-resistance is conferred on the treated goods. From the practical point of view, the chlorination/resin processes have the disadvantages mainly associated with the chlorination step, which degrades and therefore weakens the wool fibre and makes dyeing to high standards of wet-fastness more difficult. But the overriding advantage of these processes is that they are applicable to a wider range of substrates by convenient processing techniques. Thus chlorination/resin processes are effective on tops or slivers, but no polymer has yet been discovered which gives shrink-resistance when applied to unchlorinated tops. Again, long-liquor batch-exhaust processes of the chlorination/resin type have been in commercial use for the treatment of knitted garments for some years (l), whilst the development of a technology by which polymers may be exhausted from long liquor on to unchlorinated wool is still in its infancy (8). For these reasons chlorination/resin processes have been more successful in terms of weight of wool treated than the alternative processes by which polymers can be applied by padding techniques to unchlorinated woven or knitted fabrics, or to knitted garments in modified dry cleaning machines by dip176

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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KILPATRICK ET AL.

Shrink-Resist

Polymers

for

Wool

177

e x t r a c t - d r y methods. However, s i g n i f i c a n t developments have occurred i n recent years i n the technology o f the a p p l i c a t i o n o f prepolymers to u n c h l o r i n a t e d wool s u b s t r a t e s and i n the design and s y n t h e s i s o f polymers f o r t h i s purpose, typically, these prepolymers c o n s i s t o f a polymeric backbone w i t h t e r m i n a l r e a c t i v e groups. A f t e r a p p l i c a t i o n to the wool the products can be polymerised through these groups. I t i s the o b j e c t o f t h i s paper t o d i s c u s s these developments, and to attempt t o demonstrate how the p r o p e r t i e s o f the t r e a t e d wool, the s t a b i l i t y o f a p p l i c a t i o n baths, the c u r i n g c o n d i t i o n s r e q u i r e d and the s h e l f l i f e o f the polymer depend on i t s f u n c t i o n a l groups and other aspects o f i t s chemical s t r u c t u r e . Experimental M a t e r i a l s Wool F a b r i c s . The k n i t t e d f a b r i c used was s i n g l e j e r s e y , k n i t t e d from R74/2 tex 100% wool y a m to a t i g h t n e s s f a c t o r o f 13· The f a b r i c was scoured i n an aqueous s o l u t i o n o f L i s s a p o l IT (ICI, 1 g / l ) and sodium bicarbonate ( l g / l ) , at a liquor:goods r a t i o o f 40:1 f o r 20 min a t 40°C, f o l l o w e d by thorough r i n s i n g with water. The f a b r i c pH was 8. The woven f a b r i c was undyed, a l l - w o r s t e d , 2 X 2 t w i l l o f weight 192 g m-2 ( S a l t s o f S a l t a i r e L t d . , UK). The f a b r i c pH was 7·5· Polymers. These were s y n t h e s i s e d i n the l a b o r a t o r y , w i t h the exception o f the p o l y a c r y l a t e , Acramin SLN (Bayer), and Hercosett 57 (Hercules Powder Co). The s y n t h e t i c methods can be found i n the l i t e r a t u r e , as f o l l o w s : polythiomalate (2), polycarbamoyl sulphonate (p), p o l y i s o c y a n a t e (4) « p o l y t h i o s u l p h a t e (5)* p o l y t h i o g l y c o l l a t e (6) and polysulphonium bromide (7)* Other Reagents. The wetting agent used was T i n o v e t i n LB (Ciba-Geigy) and the e m u l s i f y i n g agent was L i s s a p o l NX ( I C I ) ; a l l other reagents were l a b o r a t o r y grade. Experimental Methods A p p l i c a t i o n o f Prepolymers to F a b r i c . Polymers IV and VI were e m u l s i f i e d w i t h L i s s a p o l IT (20% on weight o f polymer), and stock emulsions used to make up padding-strength emulsions w i t h other a d d i t i o n s (Table I I ) as r e q u i r e d . The remaining polymers were s o l u b l e i n the padding l i q u o r , and s o l u t i o n s were prepared immediately p r i o r to padding. S o l u t i o n s o r emulsions were padded onto weighed p i e c e s o f f a b r i c , u s i n g a l a b o r a t o r y padmangle, and the p i e c e s were subsequently reweighed to enable c a l c u l a t i o n o f the wet pick-up. They were then d r i e d i n a f o r c e d - a i r oven and steamed where necessary (see Table I I ) . H a l f o f each t r e a t e d sample was subjected to a simulated afterwash process c o n s i s t i n g o f 2 X 10 min c y c l e s i n 25 1 o f water i n an I n t e r n a t i o n a l Cubex wash

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t e s t i n g machine. The f a b r i c s were r e d r i e d at 100°C and f i n a l l y semi-decated (5 min steam). Test Methods. The f a b r i c s were wash t e s t e d 7 days a f t e r treatment. The f e l t i n g shrinkage t e s t c o n s i s t e d o f 180 min a g i t a t i o n i n the Cubex washing machine i n 15 l i t r e s o f pH 7 phosphate b u f f e r a t 40°C w i t h a 1 k g l o a d . A f t e r washing, samples were s p i n d r i e d , then l i n e d r i e d . Area shrinkage was determined by measuring p r e v i o u s l y a p p l i e d bench marks. Durable Press r a t i n g was assessed by comparison o f the f a b r i c s w i t h the AATCC r e p l i c a s (9) (D.P. r a t i n g s 1-5)· F l e x u r a l r i g i d i t y was measured by the c a n t i l e v e r bending l e n g t h method a c c o r d i n g to B r i t i s h Standard

3356:1961.

R e s u l t s and D i s c u s s i o n P r o p e r t i e s Required i n S h r i n k - R e s i s t Polymers. I t i s not d i f f i c u l t t o l i s t the c r i t e r i a which an i d e a l s h r i n k - r e s i s t polymer should s a t i s f y . T h i s l i s t c o n s i s t s o f two s e t s o f a t t r i b u t e s : one concerned w i t h the ease o f a p p l i c a t i o n o f the polymer and the other w i t h the performance and p r o p e r t i e s o f the treated f a b r i c . Since i t i s intended to d i s c u s s the polymers examined i n t h i s paper i n terms o f how n e a r l y they s a t i s f y these c r i t e r i a , i t i s as w e l l , a t t h i s stage, to c o n s i d e r i n f u l l the points i n this l i s t . Application c r i t e r i a : (i) The s h e l f l i f e o f the prepolymer concentrate, s t o r e d under normal c o n d i t i o n s , should exceed a c e r t a i n minimum, and s i x months i s probably the minimum a c c e p t a b l e . ( i i ) P r e p a r a t i o n o f the padding l i q u o r should be simple and should not r e q u i r e s p e c i a l equipment. F o r example, a prepolymer which i s i n s o l u b l e i n water may be a p p l i e d to wool f a b r i c from an aqueous emulsion, but the chemistry o f the polymer should be such t h a t i t i s p o s s i b l e f o r a s t a b l e emulsion t o be prepared by the chemical manufacturer s i n c e t h i s r e q u i r e s s p e c i a l equipment not n o r m a l l y found i n t e x t i l e f i n i s h i n g p l a n t s . ( i i i ) The prepared padding l i q u o r should be s t a b l e and usable f o r at l e a s t 8 h (a f u l l s h i f t ) a f t e r p r e p a r a t i o n , and p r e f e r a b l y f o r l o n g e r than t h i s . Of course, the padding l i q u o r must c o n t a i n any c u r i n g c a t a l y s t s which are used and t h i s tends to make i t l e s s c h e m i c a l l y s t a b l e than a l i q u o r c o n t a i n i n g the prepolymer alone. A d d i t i o n a l l y , d i l u t e emulsions may have a g r e a t e r tendency to separate o r "cream" than concentrates, ( i v ) A f t e r a p p l i c a t i o n t o the f a b r i c , the prepolymer must cure r e a d i l y , and under r e l a t i v e l y m i l d c o n d i t i o n s . I d e a l l y , d r y i n g the t r e a t e d f a b r i c i n the c o n d i t i o n s normally used f o r d r y i n g wool should be s u f f i c i e n t . Any n e c e s s i t y f o r heat c u r i n g a t e l e v a t e d temperatures i s a d i s t i n c t disadvantage because wool f i n i s h e r s o f t e n do not have f a c i l i t i e s f o r t h i s type o f treatment,

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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and i n any case, i t may damage the wool o r cause i t to yellow, p a r t i c u l a r l y i f the c l o t h i s i n an a l k a l i n e c o n d i t i o n . (v) I n the i d e a l system, afterwashing, e i t h e r to improve the f a b r i c hand o r to remove excess c a t a l y s t s or wetting agents e t c . should not be necessary. ( v i ) The c r o s s - l i n k e d polymer should have minimal e f f e c t s on the dyeing p r o p e r t i e s o f t r e a t e d wool, so t h a t u n l e v e l polymer a p p l i c a t i o n w i l l not l e a d to u n l e v e l dyeing when dyeing succeeds the s h r i n k - r e s i s t treatment. Performance c r i t e r i a : (yil) The f e l t i n g r e s i s t a n c e o f t r e a t e d f a b r i c s should enable them to survive a severe wash t e s t , at l e a s t equivalent to the maximum amount o f washing a garment w i l l r e c e i v e d u r i n g i t s a n t i c i p a t e d wear l i f e . ( v i i i ) The t r e a t e d f a b r i c i r o n ) p r o p e r t i e s , equivalent at l e a s t to a DP3 r a t i n g a f t e r severe machine washing. K n i t t e d f a b r i c s should r e t a i n good s t i t c h c l a r i t y through the machine wash. ( i x ) The cost o f the polymer and the r e q u i r e d add-on must be such that c r i t e r i a ( v i i ) and ( v i i i ) can be s a t i s f i e d a t reasonable cost. (x) The a e s t h e t i c p r o p e r t i e s o f the f i n i s h e d f a b r i c must be v i r t u a l l y i n d i s t i n g u i s h a b l e from untreated wool. In p a r t i c u l a r the process must not n o t i c e a b l y i n c r e a s e the s t i f f n e s s o r harshness of the f a b r i c , nor cause i t s hand to become greasy o r tacky. With such a l i s t of c r i t e r i a to s a t i s f y , i t i s h a r d l y s u r p r i s i n g that the i d e a l s h r i n k - r e s i s t polymer f i n i s h has yet to be found. I t i s p a r t i c u l a r l y d i f f i c u l t to f i n d polymers which have good s h e l f l i f e and a p p l i c a t i o n - b a t h s t a b i l i t y , and yet cure under m i l d c o n d i t i o n s a f t e r a p p l i c a t i o n to the f a b r i c ; the reasons f o r t h i s c o n f l i c t i n p r o p e r t i e s are q u i t e obvious. I t i s a l s o very d i f f i c u l t to produce a h i g h l e v e l of s h r i n k re s i stance combined w i t h good f a b r i c a e s t h e t i c s without washingo f f a f t e r polymer a p p l i c a t i o n to improve the f a b r i c ' s hand. Polymer S t r u c t u r e . (Table i ) . The polymers d i s c u s s e d i n t h i s paper are more a c c u r a t e l y described as r e a c t i v e , s e l f c r o s s l i n k i n g oligomers. T y p i c a l l y , they c o n s i s t e d o f a s o f t backbone s t r u c t u r e , o f t e n a p o l y ( a l k y l e n e oxide) o f molecular weight Λ<3000, to which were attached two or more s e l f c r o s s l i n k i n g r e a c t i v e groups. A f t e r a p p l i c a t i o n to the wool f a b r i c , c r o s s l i n k i n g o r chain extension r e a c t i o n s were caused to occur u n t i l the polymer molecular weight became i n f i n i t e , and the polymer was thus rendered i n s o l u b l e on the f i b r e s u r f a c e . I t i s intended, i n t h i s paper, to show how polymer s t r u c t u r e , p a r t i c u l a r l y r e a c t i v e group type, a f f e c t s performance as judged by the c r i t e r i a set out above. Polymer IV (Table i ) w i l l be described f i r s t , since two o f the other polymers were obtained from polymer I V by modifying i t s

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TABLE I THE STRUCTURES OF THE POLYMER SYSTEMS STUDIED

Polymer system

I

Polythiomalate

Backbone *

PTMO

Functional group

Nominal functionality

-OOC.CH.CH .COO2

4

SH 3

II

Polycarbamoyl sulphonate

PPO

-NH.C0.S0"Na

+

III

Polycarbamoyl sulphonate -polyacrylate

PPO/PACR

-NH.C0.S0~Na

+

IV

Polyisocyanate

PPO

-NC0(aliphatic)

3

V

Polythiosulphate

PPO

-S 0 "Na 2 3

3

VI

Polythioglycollate

PPO

-OOC.CH SH

VII

Polysulphonium bromide

PPO

+ -NH.CO.CH SR Br

*

+

3

2

2

PTMO:

poly(tetramethylene o x i d e ) d i o l ,

PPO:

poly (propylene oxide ) t r i o l , MW/V3000

PACR:

" s o f t " polyacrylate

3

2

MV/Λ/ΙΟΟΟ

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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f u n c t i o n a l groups. T h i s polymer was a polyisocyanate obtained by the r e a c t i o n o f one mole o f a poly(propylene o x i d e ) t r i o l o f molecular weight Λ/3000 w i t h three moles o f hexamethylene d i i s o c y a n a t e , thus g i v i n g an oligomer w i t h a nominal isocyanate functionality of 3 (4). R(OH)

5

+ OCN(CH ) NCO — 2

6

R f00C.HH(CH ) BC0} 2

6

(l)

?

polymer IV Although the a l i p h a t i c isocyanate groups i n polymer IV are r e a c t i v e towards water, a technique which allows the polymer t o be a p p l i e d from aqueous emulsion has been d e s c r i b e d (15) » Polymers I I and V I I were d e r i v a t i v e s o f polymer IV Polymer I I was formed by the r e a c t i o polymer IV w i t h sodium b i s u l p h i t

R'(NCO) + 3NaBS0 5

—

5

polymer IV

(2)

R« (EH.CO.SO^ITa+J^ polymer I I

The sodium s a l t o f the polycarbamoyl sulphonate (polymer I I ) was water s o l u b l e . Polymer V I I was obtained by r e a c t i o n o f polymer IV w i t h bromoacetic a c i d , f o l l o w e d by t h i o d i g l y c o l , t o give a water s o l u b l e sulphonium d e r i v a t i v e (7)* R « ( N C O ) •+ 3HOOC.CH Br — ^ R 5

2

1

(M.CO.CH^Br)^ + 3C0

2

(3)

polymer IV

^(O^OE)^

R'(M.CO.CH Br) + 2

5

polymer V I I Polymers V and VI a l s o used p o l y (propylene oxide ) t r i o l backbones, but t h e i r f u n c t i o n a l groups were attached through e s t e r l i n k a g e s , r a t h e r than the urethane groups used i n the three polymers d e s c r i b e d above. Polymer V, a water s o l u b l e p o l y ( t h i o s u l p h a t e ) , was obtained by e s t e r i f i c a t i o n o f the t r i o l w i t h c h l o r o a c e t i c a c i d , f o l l o w e d by r e a c t i o n o f the t r i s - c h l o r o a c e t a t e w i t h sodium thiosulphate (5)« R(OH)

5

+ 3HOOC.CH Cl — ^ R ( O O C . C H C l ) 2

2

+ JHgO

5

R(OOC.CH Cl) + 3 S 0 ^ — ^ R ( O O C . C H . S 0 " ) 2

5

2

2

2

5

5

+ 3C1"

polymer V

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

(5) (6)

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

182

Polymer VI was the t r i s - t h i o g l y c o l l a t e o f the p o l y (propylene oxide)triol (6). R(OH)

5

+ 3HOOC.CH SH — R ( O O C . C H S H ) . + 3^0 2

2

5

(7)

polymer VI T h i s polymer was not water s o l u b l e , and was a p p l i e d as an aqueous emulsion. Polymer I a l s o had t h i o l r e a c t i v e groups but was obtained by the e s t e r i f i c a t i o n o f three moles o f p o l y (te trame thylene oxide) o f MW 'vlOOO (H0.R 0H) w i t h f o u r moles o f t h i o m a l i c a c i d ( 2 ) . M

3HO.R."oH + 4 H00C.CH(SH)CH .C00H

»~

HO {0C.CH(SH)CH .C00R 2

polymer I The r e s u l t i n g polymer contained (nominally) f o u r t h i o l groups and two f r e e c a r b o x y l groups and was s o l u b l e i n the d i l u t e a l k a l i used as a c u r i n g c a t a l y s t ( 2 ) . F i n a l l y , polymer system I I I , was a mixture o f the p o l y ­ carbamoyl sulphonate (polymer I I ) w i t h a p o l y a c r y l a t e emulsion i n the r a t i o 1 p a r t polymer I I : 2 p a r t s p o l y a c r y l a t e ( r e s i n s o l i d s w/w). T h i s mixture has been claimed to have advantages over the polycarbamoyl sulphonate used alone ( l O ) . A p p l i c a t i o n . A l l the polymers d e s c r i b e d were a p p l i e d by immersion o f the f a b r i c to be t r e a t e d i n the polymer s o l u t i o n or emulsion, f o l l o w e d by removal o f excess i n a pad mangle. The c o n d i t i o n s r e q u i r e d f o r c u r i n g the polymers on the f a b r i c s c u r i n g c a t a l y s t , c u r i n g temperature e t c . - were o b v i o u s l y dependent on the chemistry o f the r e a c t i v e groups o f the polymers, and i n each case, the a p p l i c a t i o n methods used were those claimed i n the l i t e r a t u r e to be optimum, o r known to be optimum from p r e v i o u s work i n these l a b o r a t o r i e s . The c o n d i t i o n s used are l i s t e d i n Table I I , together w i t h t h e i r sources. Most o f the polymers r e q u i r e d m i l d l y a l k a l i n e o r n e u t r a l c o n d i t i o n s f o r optimum cure, and a l k a l i n e s a l t s were added to the pad l i q u o r s i n a l l cases except the p o l y i s o c y a n a t e (polymer I V ) . I n a d d i t i o n , the p o l y t h i o g l y c o l l a t e p a d - l i q u o r (polymer VI) contained a small amount o f a polyamide e p i c h l o r h y d r i n r e s i n (Hercosett 57) which has been claimed to improve the performance o f t h i s polymer (6). C u r i n g c o n d i t i o n s a g a i n v a r i e d from one polymer to another. The p o l y t h i o m a l a t e cured by d r y i n g a t 80OC ( g ) , and the p o l y ­ t h i o g l y c o l l a t e cured i f i t was s t o r e d a t ambient c o n d i t i o n s f o r one day a f t e r d r y i n g (6). Steaming brought about f u l l cure i n the case o f the p o l y ­ isocyanate and i t s two d e r i v a t i v e s (5*11^12,13) and to cure the

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

Polythiosulphate

Polythioglycollate

V

VI

* **

2

5

5

3

5 g / l urea +5 g / l Na a c e t a t e

+ H57**

10 g / l NaHC0

2

+ 10 g / l N a S 0

10 g / l N a C 0

-

5

g/l

1 g/l

*

1 g/i

1 g/i

1 e/i

5

V e t t i n g agent

Sequence

pad - d r y (10 min/l00°C) - steam (2 min)

(13)

(6)

(5)

pad - d r y (10 min/l30°C)

pad- d r y (10 min/l20°C) -- s t o r e

(13)

(10)

pad - d r y (15 min/lOO°C) - steam (2 min)

pad - d r y (15 min/lOO°C) - steam (2 min)

(3)

(2)

Reference

pad - d r y (15 min/lOO°C) - steam (2 min)

pad - d r y (10 min/l20°C)

Application

E m u l s i f y i n g agent present H57 = 10/q H e r c o s e t t 57 ( r e s i n s o l i d s ) on weight of·polythioglycollate.

V I I I Polysulphonium bromide

Polyisocyanate

Polycarbamoyl sulphonate 5 g / l NaHCO^ -polyacrylate (l:2)

III

IV

Polycarbamoyl sulphonate 5 g / l NaHCO^

II

2

Polythiomalate

20 g / l N a C 0

Catalysts

pad l i q u o r a d d i t i o n s

I

Polymer

APPLICATION CONDITIONS ÏÏSgD FOR SHRINK-RESIST

TABLE-II

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p o l y t h i o sulphate, i t was necessary to dry at a r a t h e r h i g h e r temperature than i s normal f o r wool f a b r i c s (5)· Pad-Liquor S t a b i l i t y . Pad l i q u o r s t a b i l i t y was assessed by t r e a t i n g f a b r i c s i n f r e s h pad-baths and a l s o i n baths which had been prepared and s t o r e d f o r p e r i o d s of up to 5 days. The l i q u o r s were s t o r e d i n the l a b o r a t o r y i n open v e s s e l s . Table I I I contains the r e s u l t s of t h i s experiment, and shows that the prepared pad l i q u o r s were w i d e l y d i f f e r e n t i n s t a b i l i t y . The p o l y i s o c y a n a t e emulsion l o s t i t s a b i l i t y to s h r i n k - r e s i s t the f a b r i c a f t e r storage f o r one day. Although the appearance of the l i q u o r was not markedly changed, t i t r a t i o n of the one day o l d emulsion ( l l ) showed i t s isocyanate content to be zero, i n d i c a t i n g that premature r e a c t i o n sulphate s o l u t i o n was a l s g e l a t i o n occurred so that i t was impossible to pad the f a b r i c through the bath. A l l the other polymers c o u l d be used s u c c e s s f u l l y a f t e r 5 days. The p o l y t h i o g l y c o l l a t e emulsion tended to separate but there was no apparent chemical i n s t a b i l i t y , and s t i r r i n g the l i q u o r restored i t s usefulness. Shrink-Re s i s t E f f ectivene s s. Shrink-resist effectiveness has been d e f i n e d i n terms o f the t h r e s h o l d treatment l e v e l (TTL) i.e, the minimum add-on of polymer which w i l l give a s p e c i f i e d l e v e l of w a s h a b i l i t y when a p p l i e d to a p a r t i c u l a r f a b r i c ( 14) · Here, the t r e a t e d f a b r i c s were r e q u i r e d to have l e s s than 5% area f e l t i n g shrinkage when washed a c c o r d i n g to IWS Test Method 185, that i s 3h a g i t a t i o n i n 15 1 o f pH 7 b u f f e r at 40 C i n an I n t e r n a t i o n a l Cubex washtesting machine. TTL was determined by i n t e r p o l a t i o n from p l o t s of area shrinkage against polymer add-on. P l o t s f o r three of the polymers i n v e s t i g a t e d , when a p p l i e d to a woven worsted f a b r i c are shown as examples i n P i g . 1. TTL values f o r a l l the polymers on t h i s f a b r i c and a k n i t t e d botany f a b r i c are given i n Table IV. In a s i m i l a r manner, the add-on r e q u i r e d to give a DP r a t i n g o f 5 on the woven f a b r i c was determined f o r each polymer. Two f a c t o r s are immediately apparent from Table IV. The f i r s t i s the wide v a r i a t i o n i n the amounts of d i f f e r e n t polymers r e q u i r e d to achieve s i m i l a r e f f e c t s , and the second i s the f a c t that the k n i t t e d f a b r i c r e q u i r e d a much h i g h e r add-on of a l l the polymers than the woven f a b r i c . To o b t a i n the d e s i r e d l e v e l of w a s h a b i l i t y , i t was necessary to apply 5-7 times as much o f the l e a s t e f f e c t i v e polymer ( V I l ) as of the two most e f f e c t i v e polymers ( i and I I ) . The other polymers had intermediate performance, but even the most e f f e c t i v e of these, the p o l y i s o c y a n a t e ( I V ) , was o n l y h a l f as e f f e c t i v e as polymers I and I I . I t i s of i n t e r e s t to c o n s i d e r the c u r i n g r e a c t i o n s of the v a r i o u s polymers i n g r e a t e r d e t a i l , and to examine more c l o s e l y

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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Shrink-Resist Polymers for Wool

TABLE I I I THE EFFECT OF AGE OF PAD-LIQUOR ON THE SHRINKAGE OF TREATED FABRIC

Polymer system

Add on

Area shrinkage (%) of f a b r i c s

I

Polythiomalate

1.6

1

2

4

3

II

Polycarbamoyl sulphonate

1.6

2

0

1

2

III

Polycarbamoyl sulphonate -polyacrylate

3.0

1

0

2

2

IV

Polyisocyanate

2.0

0

43

45

45

V

Polythiosulphate

2.5

0

pad-liquor gelled a f t e r approx. 6 hours

VI

Polythioglycollate

3.0

2

2

1

2

VII

Polysulphonium bromide

4.0

2

0

0

2

Untreated f a b r i c

-

58

Woven worsted f a b r i c See text f o r d e t a i l s of application Wash test: 3h, 15 1 Cubex

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

TABLE IV

THE EFFECTIVENESS OF POLYMERS IN CONFERRING SHRINK-RE5ISTANCE AND SMOOTH DRYING CHARACTERISTICS ON WOVEN AND KNITTED FABRICS

Polymer system

Woven f a b r i c AS<5#

DP>3

Knitted f a b r i c AS<5%

I

Polythiomalate

0.6

1.2

1.1

II

Polycarbamoyl sulphonate

0.6

0.Θ

0.8

III

Polycarbamoyl sulphonate -polyacrylate ( l : 2 )

1.5

1.8

2.3

IV

Polyisocyanate

1.3

2.2

2.6

V

Polythio sulphate

1.5

3.2

4.0

VI

Polythioglycollate

1.7

3.2

3.5

VII

Polysulphonium bromide

3.2

6.0

7.0

AS =

area f e l t i n g shrinkage a f t e r 3h 15 1 Cubex wash test

DP =

durable press r a t i n g

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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the type o f cured s t r u c t u r e t o be expected i n each case, i n order t o f i n d an e x p l a n a t i o n f o r the v e r y d i f f e r e n t performance o f these a p p a r e n t l y s i m i l a r polymers. Polymers V and VI, which have t h i o s u l p h a t e and t h i o g l y c o l l a t e r e a c t i v e groups r e s p e c t i v e l y , are both b e l i e v e d t o form p o l y d i sulphide s when cured on the wool. The t h i o g l y c o l l a t e cures by a l k a l i n e - c a t a l y s e d a e r i a l o x i d a t i o n o f i t s t h i o l groups (6) 9

RSH +

[θ]

— * ~ R.SS.R + H 0

(9)

2

and the t h i o s u l p h a t e by a l k a l i n e h y d r o l y s i s o f i t s r e a c t i v e groups, f o l l o w e d by r e a c t i o n o f the t h i o l so formed w i t h a second t h i o ­ sulphate group. R.SSO^ + O H " — R . S H + R.SSCy

+ R . S H - » - R . S S . R + HSO^"

(ll)

Thus, v i r t u a l l y i d e n t i c a l cured s t r u c t u r e s would be expected from these two polymers, and indeed, t h e i r l e v e l s o f performance on both k n i t t e d and woven f a b r i c were c l o s e l y s i m i l a r . The p o l y t h i o m a l a t e , however, was three times as e f f e c t i v e as e i t h e r the p o l y t h i o g l y c o l l a t e o r the p o l y t h i o s u l p h a t e and t h i s may be due t o one o r a number o f the f o l l o w i n g d i f f e r e n c e s i n the chemical r e a c t i v i t y and s t r u c t u r e o f the polymers. (i) The polythiomalate was s o l u b l e i n the a l k a l i n e pad l i q u o r which was used f o r i t s a p p l i c a t i o n , i n c o n t r a s t t o the t h i o g l y ­ c o l l a t e which was a p p l i e d as an emulsion. Thus there was more i n t i m a t e contact between the p o l y t h i o m a l a t e and the c a t a l y s i n g medium, which may w e l l have l e d t o more e f f i c i e n t c u r i n g . I n f a c t , i t i s p o s s i b l e t o cure the thiomalate under m i l d e r c o n d i t i o n s than those r e q u i r e d f o r the t h i o g l y c o l l a t e ( 2 ) . (ii) I n the thiomalate, two o f the f o u r t h i o l groups are much more h i g h l y a c i d i c than normal t h i o l groups because they are a c t i v a t e d by two neighbouring carbonyl groups ( s t r u c t u r e A below). By c o n t r a s t , the t h i o l groups o f the t h i o g l y c o l l a t e are a c t i v a t e d by o n l y one carbonyl group ( s t r u c t u r e Β below). -0-Ç < — C H - ^ C H — C - 0 0

SH A:

thiomalate

^0

-0-C <—CEL**—SH ^0 B:

thioglycollate

Since the t h i o l anion i s b e l i e v e d t o be the r e a c t i v e s p e c i e s i n the o x i d a t i o n r e a c t i o n to form the d i s u l p h i d e c r o s s l i n k s (hence the need f o r a l k a l i n e c a t a l y s i s ) i t i s t o be expected t h a t the p o l y t h i o m a l a t e would cure more r e a d i l y , and p o s s i b l y more completely than the p o l y t h i o g l y c o l l a t e . ( i i i ) The polythiomalate has a nominal f u n c t i o n a l i t y o f 4, compared w i t h three f o r the other polymers. T h i s i n c r e a s e d

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

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f u n c t i o n a l i t y w i l l l e a d t o the more r a p i d formation o f a h i g h molecular weight product on the f i b r e s u r f a c e , by f a c i l i t a t i n g b r a n c h i n g r e a c t i o n s (15)· ( i v ) The p r o p e r t i e s o f the d i f f e r e n t p o l y ( a l k y l e n e oxide) backbones used i n the two polymers were d i f f e r e n t . The t h i o g l y c o l l a t e was based on p o l y (propylene oxide) w h i l s t the thiomalate was obtained by e s t e r i f i c a t i o n o f poly(tetramethylene oxide) ( p o l y t e t r a h y d r o f u r a n ) . PTMO i s a much harder polymer than PPO because o f the g r e a t e r l e v e l o f non-covalent i n t e r a c t i o n s between i t s c h a i n s . Thus a PTMO o f MW/vlOOO i s s o l i d a t room temperature w h i l s t PPO o f s i m i l a r M i s a l i q u i d . These non-covalent bonds i n PTMO are b e l i e v e d t o a c t as e x t r a , r e i n f o r c i n g c r o s s l i n k s i n the cured p o l y t h i o m a l a t e , thus i n c r e a s i n g i t s e f f i c i e n c y as a s h r i n k - r e s i s t polymer. (2), which compared the s h r i n k - r e s i s p o l y t h i o g l y c o l l a t e s an p o l y t h i o m a l a t backbones o f v a r i o u s molecular weight and f u n c t i o n a l i t y , support t h i s theory. The three remaining polymers ( i g n o r i n g the mixed P C S p o l y a c r y l a t e system f o r the moment) a r e a l l based on p o l y p r o p y lene o x i d e ) t r i o l s . Indeed polymers I I and V I I a r e d e r i v a t i v e s o f polymer IV. The primary c u r i n g r e a c t i o n o f the p o l y i s o c y a n a t e (polymer IV) i s h y d r o l y s i s , f o l l o w e d by r e a c t i o n o f the amine formed w i t h a second isocyanate group t o g i v e a p o l y u r e a ( l 6 ) . R.NCQ + H 0

S

L

0

2

R.NCO +

R.ra

2

f a s

W

»

R.NH

V

+ C0

2

2

R.MCOM.R

(12)

(13)

The polycarbamoyl sulphonate (polymer I I ) which was the b i s u l p h i t e adduct o f polymer IV, may be regarded as a blocked isocyanate capable o f u n b l o c k i n g t o g i v e a f r e e isocyanate which then cures as shown above. A l t e r n a t i v e l y i t may be c o n s i d e r e d as a r e a c t i v e polymer i n i t s own r i g h t , which does n o t n e c e s s a r i l y cure v i a a r e a c t i o n sequence i n v o l v i n g the intermediate formation o f f r e e i s o c y a n a t e : R.M.CO.SO"^

^ R.NCO + HSO~

(H)

|+H 0 2

'R.EH R.M.CO.SOJ + R . M

2

2

+ HSO"

^ R . M C O M . R + HSOj

(15) (l6)

The polycarbamoyl sulphonate i s known t o cure more r a p i d l y than the p o l y i s o c y a n a t e when t r e a t e d wool f a b r i c s a r e steamed (l2) and t h i s can o n l y be caused by an i n c r e a s e d r a t e o f f o r m a t i o n o f the amine, s i n c e the subsequent r e a c t i o n between the amine and the isocyanate i s f a s t and t h e r e f o r e not r a t e - d e t e r m i n i n g . There

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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189

are two p o s s i b l e explanations f o r the i n c r e a s e d r a t e o f amine formation: e i t h e r the polycarbamoyl sulphonate behaves as an a c t i v a t e d i s o c y a n a t e , i . e . r e a c t i o n (15) i s f a s t e r than r e a c t i o n (l2), o r the i n c r e a s e d h y d r o p h i l i c i t y o f the polycarbamoyl sulphonate over the p o l y i s o c y a n a t e allows e a s i e r access o f water to the s i t e s o f r e a c t i o n . The p o l y i s o c y a n a t e (polymer IV) was more e f f e c t i v e as a s h r i n k - r e s i s t agent than e i t h e r the p o l y t h i o s u l p h a t e ("V") o r the p o l y t h i o g l y c o l l a t e ( V l ) d e s p i t e the f a c t that a l l three polymers had c l o s e l y s i m i l a r backbones. T h i s has been a s c r i b e d t o the p o s s i b i l i t y o f hydrogen bond formation between the urethane and u r e a groups o f the cured p o l y i s o c y a n a t e which c o n t r i b u t e t o the cohesive p r o p e r t i e s o f the polymer (17)· No such p o s s i b i l i t y i s a v a i l a b l e i n the cure s u l p h u r - c o n t a i n i n g polymers I t i s d i f f i c u l t t o e x p l a i n the i n c r e a s e i n s h r i n k - r e s i s t e f f i c i e n c y obtained by c o n v e r t i n g the p o l y i s o c y a n a t e t o the polycarbamoyl sulphonate. A f t e r p o l y m e r i s a t i o n these two p r e ­ polymers should g i v e c l o s e l y s i m i l a r networks, although c e r t a i n l y there i s the p o s s i b i l i t y o f more e f f i c i e n t c u r i n g i n the polycarbamoyl sulphonate. I n terms o f o v e r a l l washing performance o f t r e a t e d f a b r i c s , t h i s polymer was the most e f f e c t i v e o f the seven systems s t u d i e d . The polysulphonium bromide, although i t i s prepared from the p o l y i s o c y a n a t e cannot r e v e r t t o the p o l y i s o c y a n a t e by u n b l o c k i n g r e a c t i o n s because a carbon atom i s l o s t (as CO2) i n the r e a c t i o n o f the bromoacetic a c i d w i t h the p o l y i s o c y a n a t e ( r e a c t i o n 3)· Tn© product o f t h i s r e a c t i o n i s a s u b s t i t u t e d amide. The c u r i n g r e a c t i o n s o f the sulphonium group are r a t h e r obscure, and j u d g i n g by i t s s h r i n k - r e s i s t e f f e c t i v e n e s s , these r e a c t i o n s are not v e r y e f f i c i e n t . There are two p o s s i b i l i t i e s . F i r s t l y , the sulphonium group may act as a l e a v i n g group, a l l o w i n g r e a c t i o n of the polysulphonium bromide w i t h a c t i v e hydrogen i n amine, t h i o l o r hydroxyl groups i n the wool s u r f a c e : R.M.CO.CH S(C H OH) 2

2

4

2

R.M.CO.CH .M 2

+ EE 2

Wool

Wool + S ( C H O H ) 2

4

2

+ H

+

Reactive dyes based on t h i s p r i n c i p l e have been d e s c r i b e d (18), but d y e s t u f f s are able t o penetrate the f i b r e under normal dyeing c o n d i t i o n s , whereas i t i s u n l i k e l y that a polymer o f Λ/3000 MW would be able t o do so when a p p l i e d by padding. Thus r e a c t i o n o f the polysulphonium bromide w i t h the f i b r e , i f i t occurs a t a l l , must be c o n f i n e d t o the s u r f a c e , and would be expected t o be i n e f f i c i e n t . The second p o s s i b i l i t y i s that the polysulphonium bromide undergoes c r o s s l i n k i n g r e a c t i o n s w i t h the urea which was i n c l u d e d i n the padding l i q u o r :

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

(17)

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

+

(18) There i s l i m i t e d experimental evidence to support both these p o s s i b l e c u r i n g mechanisms. The sulphonium polymer i s known to "be more e f f e c t i v e when a p p l i e d w i t h "bisulphite (19)· The "bisulphite would r e a c t w i t h the wool t o produce t h i o l groups which c o u l d then r e a c t w i t h the polymer as i n the f i r s t mechanism d e s c r i b e d . On the other hand, omission o f urea from the padl i q u o r decreases the shri n k - r e sis t e f f e c t i v e n e s s o f the polymer, which supports the second mechanism. I t i s u n l i k e l y that the r e l a t i v e l y small amount o f u r e a used would be s u f f i c i e n t to open up the f i b r e s t r u c t u r e b the f i b r e i n t e r i o r mor i t s r e a c t i o n w i t h the wool. The mixed polymer system, the polycarbamoyl sulphonatep o l y a c r y l a t e mixture ( i l l ) was o f approximately the same e f f e c t ­ i v e n e s s , i n terms o f t o t a l polymer add-on, as the p o l y i s o c y a n a t e (TV). However, comparison o f the r e s u l t s obtained f o r t h i s mixed system w i t h those f o r the polycarbamoyl sulphonate ( i l ) alone, show that the i n c l u s i o n o f the p o l y a c r y l a t e c o n t r i b u t e d v e r y l i t t l e to the washing performance o f t r e a t e d f a b r i c s . As w i l l be shown l a t e r , the polycarbamoyl sulphonate alone a l s o had advantages over the p o l y a c r y l a t e mixture i n terms o f hand a t a given l e v e l o f s h r i n k - r e s i s t a n c e . However, use o f the p o l y acrylate-polycarbamoyl sulphonate system may have advantages i n improving p r o p e r t i e s which were not measured i n t h i s study. Most o f the polymers i n v e s t i g a t e d gave adequate smooth d r y i n g (ΠΡ r a t i n g g r e a t e r than 3) on the woven worsted a t approximately twice the minimum add-on r e q u i r e d f o r the e l i m i n a t i o n o f f e l t i n g shrinkage. A r a t h e r g r e a t e r add-on than t h i s was u s u a l l y r e q u i r e d to s t a b i l i s e the s i n g l e j e r s e y f a b r i c . The two systems c o n t a i n i n g polycarbamoyl sulphonate ( I I and I I I ) were e x c e p t i o n a l i n g i v i n g good smooth d r y i n g o f the woven f a b r i c and s t a b i l i s a t i o n o f the k n i t t e d f a b r i c a t o n l y 1.3-1· 5 times the add-on r e q u i r e d t o g i v e a n o n - f e l t i n g f i n i s h on the woven worsted. The performance of the polymer f i n i s h e s has o n l y been s t u d i e d on two f a b r i c s , and these f a b r i c s were found to r e q u i r e q u i t e d i f f e r e n t amounts o f polymer f o r the achievement o f the same l e v e l o f a n t i f e l t i n g behaviour. However, the r a n k i n g o f the polymers i n terms o f s h r i n k - r e s i s t e f f e c t i v e n e s s was o n l y s l i g h t l y d i f f e r e n t on the two f a b r i c s , so although i t i s not p o s s i b l e to e x t r a p o l a t e these r e s u l t s to other f a b r i c s w i t h absolute confidence, i t i s probably t r u e to say that the r a n k i n g o f the polymers would not change g r e a t l y i f the experiments were to be repeated on other f a b r i c s . In f a c t , the two f a b r i c s used were chosen s p e c i f i c a l l y because the woven worsted was known from past experience to be q u i t e easy to s h r i n k - r e s i s t , w h i l s t the s i n g l e

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

11.

KILPATRICK ET AL.

Shrink-Resîst

Polymers for Wool

191

j e r s e y was known to be e x c e p t i o n a l l y d i f f i c u l t . Hand o f Treated F a b r i c s . The hand o f t e x t i l e f a b r i c s i s n o t o r i o u s l y d i f f i c u l t to measure q u a n t i t a t i v e l y , but i n the case o f polymer-treated woven wool f a b r i c s , experience has shown t h a t f l e x u r a l r i g i d i t y measurements c o r r e l a t e q u i t e w e l l w i t h s u b j e c t i v e hand r a t i n g s , provided t h a t the polymer treatment does not render the surface o f the f a b r i c greasy, tacky or harsh. A c c o r d i n g l y , f l e x u r a l r i g i d i t y measurements were used i n t h i s study f o r the o b j e c t i v e assessment o f changes i n hand brought about by polymer treatment o f the woven worsted f a b r i c . The i n c r e a s e i n s t i f f n e s s which occurs when a wool f a b r i c i s t r e a t e d with a s h r i n k - r e s i s t polymer i s o n l y o f i n t e r e s t i n r e l a t i o n to the f a b r i c ' l e v e l f washability d i vie f th v e r y d i f f e r e n t TTL value meaningless to conside rigidity a f u n c t i o n o f polymer add-on. In F i g . 2, t h e r e f o r e , f l e x u r a l r i g i d i t y has been p l o t t e d against area f e l t i n g shrinkage, so that d i r e c t comparison can be made between s t i f f n e s s and washing performance. I n a d d i t i o n , Table V g i v e s the f l e x u r a l r i g i d i t y values o f samples o f the woven worsted t r e a t e d with the minimum add-on o f polymer r e q u i r e d to give l e s s than 5% area f e l t i n g shrinkage. The r e s u l t s i n Table V and the curves i n F i g . 2 were obtained by i n t e r p o l a t i o n s from p l o t s o f f l e x u r a l r i g i d i t y and area f e l t i n g shrinkage against polymer add-on, as shown i n F i g . 1. F i g . 2 shows that w i t h a l l the polymer treatments, f l e x u r a l r i g i d i t y i n c r e a s e d as area f e l t i n g shrinkage decreased, up to the p o i n t where shrinkage was e l i m i n a t e d . F l e x u r a l r i g i d i t y then continued to i n c r e a s e as polymer add-on was i n c r e a s e d f u r t h e r . Polymers I and I I , which were the most e f f e c t i v e polymers i n terms o f add-on r e q u i r e d to give machine w a s h a b i l i t y , were a l s o the best w i t h regard to f a b r i c hand at t h i s l e v e l o f w a s h a b i l i t y . However, there was no general r e l a t i o n s h i p between the s h r i n k r e s i s t e f f e c t i v e n e s s o f a polymer and the hand o f t r e a t e d f a b r i c s at the polymer add-on corresponding to TTL. The a d d i t i o n o f p o l y a c r y l a t e to the polycarbamoyl sulphonate ( i l ) had the e f f e c t o f i n c r e a s i n g the f l e x u r a l r i g i d i t y of the t r e a t e d f a b r i c s without a commensurate decrease i n t h e i r f e l t i n g shrinkage v a l u e s . An i n t e r e s t i n g aspect o f F i g . 2 i s the d i f f e r e n t shapes o f the curves, e s p e c i a l l y a t low $hrinkage v a l u e s . F a b r i c s t r e a t e d w i t h the three polymers ( l , V and VI) which cure v i a formation o f p o l y d i s u l p h i d e c r o s s l i n k s i n c r e a s e d markedly i n s t i f f n e s s as p o l y mer add-on was i n c r e a s e d s u f f i c i e n t l y to reduce shrinkage from 5% to zero, w h i l s t the f o u r polyisocyanate-based polymers d i d not show t h i s t r e n d . This d i f f e r e n c e was due p a r t l y to the g r e a t e r amount o f p o l y d i sulphide-forming polymer which was necessary to b r i n g about t h i s f i n a l r e d u c t i o n i n shrinkage, and p a r t l y to the shape o f the f l e x u r a l r i g i d i t y versus add-on curves f o r these polymers which were steeper than the curves f o r the polyisocyanate-

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TABLE V

THE FLEXURAL RIGIDITY OF POLYMER TREATED WOVEN WORSTED FABRIC AT THRESHOLD TREATMENT LEVEL

Polymer system

(% oww)

treatment

washing**

I

Polythiomalate

0.6

195

150

II

Polycarbamoyl sulphonate

0.6

200

155

III

Polycarbamoyl sulphonate -polyacrylate

1.5

245

175

IV

Polyisocyanate

1.3

285

185

V

Polythiosulphate

1.5

310

175

VI

Polythioglycollate

1.7

240

195

VII

Polysulphonium bromide

5.2

260

185

-

110

Untreated control

Minimum add-on required to give <5$ area f e l t i n g a f t e r 3h 15 1 Cubex wash t e s t . 2 X 10 min agitation i n 25 1 water i n International Cubex wash tester.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

11.

KiLPATRiCK E T A L .

Shrink-Resist

Polymers for

Wool

193

Polycarbamoyl sulphonate φ = AS,

Polymer add-on

Q=FR

(%)

Figure 1. The rehtionship between area felting shrinkage (AS), flexural rigidity (FR), and polymer add-on for wool worsted fabric treated with three reactive polypropylene oxide derivatives

0

100

200 Flexural rigidity

300

400

( mg cm )

Figure 2. The relationship between area felting shrink­ age and flexural rigidity of wool worsted fabric treated with seven reactive prepolymers. For key, see Table I.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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based polymers. There may be some connection between t h i s phenomenon and the f a c t t h a t the r a t i o between the add-on l e v e l s r e q u i r e d to achieve s h r i n k - r e s i s t a n c e i n the k n i t t e d f a b r i c and the woven worsted f a b r i c was g r e a t e r i n the case o f the p o l y d i s u l p h i d e polymers, as was the r a t i o between the polymer l e v e l s r e q u i r e d f o r the attainment o f smooth d r y i n g and s h r i n k - r e s i stance on the woven f a b r i c . Shrink-re s i stance o f the k n i t t e d f a b r i c and smooth d r y i n g i n the woven were o b v i o u s l y more d i f f i c u l t to achieve, and the polymer add-on r e q u i r e d probably corresponds to r a t h e r more than t h a t r e q u i r e d f o r the t o t a l e l i m i n a t i o n o f f e l t i n g shrinkage i n the woven worsted. A l l the polymers d i s c u s s e d here are b e l i e v e d to give s h r i n k re s i stance by a mechanism i n v o l v i n g the formation o f f i b r e - f i b r e bonds o r spot-welds i n f i b r e - f i b r e bonds preven occurs when wool f a b r i c s f e l t , p r o v i d e d they are s t r o n g enough t o withstand the f o r c e s of a g i t a t i o n i n washing. Breakdown o f the bonds can occur e i t h e r by adhesive f a i l u r e between the polymer and the wool, o r by cohesive f a i l u r e o f the polymer. Scanning e l e c t r o n m i c r o s c o p i c evidence ( l l ) i n d i c a t e s that i n c r e a s i n g the polymer add-on does not normally l e a d t o an i n c r e a s e d number o f f i b r e - f i b r e bonds; r a t h e r , i t r e s u l t s i n the formation o f t h i c k e r bonds and i n the coalescence o f the t h i n n e r bonds formed at lower add-on. The s t i f f n e s s o f polymer t r e a t e d f a b r i c s w i l l be i n c r e a s e d by the formation o f f i b r e - f i b r e bonds to an degree which depends on the e x t e n s i b i l i t y and o t h e r p h y s i c a l p r o p e r t i e s o f the polymer, and on the number and t h i c k n e s s o f the bonds. The r e s u l t s presented here show that on balance, the achievement o f s h r i n k - r e s i stance by means o f the t h i n n e r and stronger f i b r e - f i b r e bonds p r o v i d e d a t lower add-on by the more e f f e c t i v e polymers leads to b e t t e r hand than when s h r i n k re s i stance i s obtained by treatment at a h i g h e r polymer add-on w i t h a weaker polymer, or a polymer which does not açLhere e f f i c i e n t l y t o the f i b r e . The hand o f polymer t r e a t e d wool f a b r i c s can be improved by u s i n g a pad-cure-afterwash f i n i s h i n g route and the e f f e c t s o f u s i n g t h i s route on f l e x u r a l r i g i d i t y are shown i n Table V. Afterwashing was simulated by a v e r y g e n t l e wash i n an I n t e r n a t i o n a l Cubex machine. I n a l l cases, f l e x u r a l r i g i d i t y was reduced by the afterwash procedure, and t h i s must correspond to the breakdown o f the weakest i n t e r f i b r e bonds, which presumably do not c o n t r i b u t e s i g n i f i c a n t l y t o s h r i n k - r e s i s tance, since the f o r c e s a p p l i e d to the f a b r i c d u r i n g the simulated afterwash process were not as h i g h as the f o r c e s a p p l i e d d u r i n g the wash t e s t . The r e d u c t i o n s i n s t i f f n e s s which occurred i n the f a b r i c s t r e a t e d w i t h the l e s s e f f e c t i v e polymers were, on the whole, g r e a t e r than those o c c u r r i n g i n f a b r i c s t r e a t e d w i t h the more e f f e c t i v e polymers, but the l a t t e r s t i l l had lower f l e x u r a l r i g i d i t y a f t e r the a f terwashing process. T h i s i n d i c a t e s t h a t the l e s s e f f e c t i v e polymers formed a r e l a t i v e l y l a r g e r

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

11.

KiLPATRicK E T A L .

Shrink-Resist

Polymers

for

Wool

195

number o f weak f i b r e - f i b r e bonds, which has an adverse e f f e c t on f a b r i c hand before washing, yet were so e a s i l y broken that they d i d not c o n t r i b u t e to the s3irink-re s i stance of the f a b r i c . Furthermore, s i n c e the f a b r i c s t r e a t e d with the more e f f e c t i v e polymers were l e s s s t i f f a f t e r a m i l d washing treatment than the f a b r i c s t r e a t e d with the l e s s e f f e c t i v e polymers, i t appears t h a t the f i b r e - f i b r e bonds which do c o n t r i b u t e to s l i r i n k - r e s i s t ance are stronger i n the case of the more e f f e c t i v e polymers, and t h a t fewer bonds, or bonds o f smaller dimension, are r e q u i r e d to give a s p e c i f i e d l e v e l o f shrinkage c o n t r o l . Conclusions (i) Of the seven polyme s h r i n k - r e s i s t processes thiomalate (polymer l ) and the p o l y (propylene oxide )-polycarbamoyl sulphonate (polymer I I ) gave the best r e s u l t s i n terms o f the s t a b i l i t y of the p a d - l i q u o r , the s h r i n k - r e s i s t e f f e c t i v e n e s s , and the hand o f t r e a t e d f a b r i c s f o r a given l e v e l of s h r i n k resistance. The g r e a t e r e f f e c t i v e n e s s of these two polymers i s a s c r i b e d to the presence of non-covalent c r o s s l i n k i n g i n the cured polymer networks i n a d d i t i o n to the covalent c r o s s l i n k s formed by t h e i r curing reactions. (ii) The add-on of the v a r i o u s polymers r e q u i r e d f o r s h r i n k r e s i s t treatment of a s i n g l e j e r s e y k n i t t e d f a b r i c was always higher than the add-on r e q u i r e d to s h r i n k - r e s i s t a woven worsted f a b r i c , but the r a t i o between the two add-on l e v e l s was d i f f e r e n t f o r d i f f e r e n t polymers. ( i i i ) The polymer add-on r e q u i r e d to give good smooth d r y i n g c h a r a c t e r i s t i c s to t r e a t e d f a b r i c s was g r e a t e r than that r e q u i r e d f o r s h r i n k - r e s i s t treatments. The r a t i o between these two add-on l e v e l s again v a r i e d w i t h polymer composition, and polymers which r e q u i r e d r e l a t i v e l y higher add-on to prevent shrinkage i n the k n i t t e d f a b r i c a l s o r e q u i r e d higher add-on to give good DP r a t i n g s i n the woven f a b r i c . ( i v ) Measurements of f a b r i c s t i f f n e s s immediately a f t e r polymer treatment and a f t e r gentle washing i n d i c a t e d t h a t the l e s s e f f e c t i v e polymers ( i n terms o f the add-on r e q u i r e d to produce a given l e v e l of s h r i n k - r e s i stance) formed a r e l a t i v e l y l a r g e number o f weak f i b r e - f i b r e bonds which i n c r e a s e d the s t i f f n e s s o f the t r e a t e d f a b r i c , but were broken by gentle washing and t h e r e f o r e c o u l d not c o n t r i b u t e s i g n i f i c a n t l y to s h r i n k - r e s i s tance. Summary Seven s h r i n k - r e s i s t polymer systems f o r a p p l i c a t i o n to wool f a b r i c s by aqueous padding procedures have been compared. A l l the polymers were p o l y ( a l k y l e n e oxide)-based, and f i v e d i f f e r e n t r e a c t i v e or s e l f - c r o s s l i n k i n g groups were used. I t has been

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

shorn that properties such as threshold treatment level (i.e. minimum add-on of polymer required to give a specified level of shrinkage control), the hand of treated fabrics, the shelf-life of the polymer, and the stability of the formulated pad-liquor are all dependent upon polymer structure. Those polymers which cured to form networks which were reinforced by non-covalent bonding (e.g. hydrogen bonding in polyurethane/polyureas, or hydrophobic interactions between backbone chains) were found to give optimum results in terms of shrink-resist effectiveness and the hand of treated fabrics. Acknowle dgement s The authors wish t Peter Greenhill and Davi for valuable technical assistance.

Davi

Literature Cited 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19.

Mills, J.H. and Smith, P., Chem Tech, (1973), 3, 748. Kilpatrick, D.J. and Shaw, T., Proc. 5th Intern. Wool Text. Res. Conf., (1975), V, 19. Guise, G.B. and Jackson, M.A., J . Text. Inst., (1973), 64, 665. U.S. Patent, 3, 558, 264 (1963). Bell, V.A. and Lewis, D.M., Proc. 5th Intern. Wool Text. Res. Conf. (1975), III, 595. Brown, T.D., Rushforth, Μ.Α., Shaw, T., Dobinson, Β., Massy, D.J.R., Wilson, W. and Winterbottom, Κ., Text. Res. J., (1976), 46, 170. British Patent, 1, 259, 048 (1972). Rippon, J.A., J . Soc. Dyers Col., (1975), 91, 405. AATCC Test Method 124-1975. Anon., Internat. Dyer, (1976), 155, 204. Rushforth, M.A. and Rippon, J.A., in preparation. Rippon, J.A. and Rushforth, M.A., Textilveredlung, (1976), 11, 224. Reich, F., Bayer Farben Rev., (1969), 15, 53. Guise, G.B., and Rushforth, M.A., J . Soc. Dyers Col., (1975), 91, 305. Guise, G.B., and Rushforth, M.A., J . Soc. Dyers Col., (1975), 91, 389. Saunders, J.H. and Frisch, K.C., in "High Polymers", Vol. XVI, 457, Interscience, New York, (1964). Rippon, J.A. and Rushforth, M.A. Textilveredlung, (1976), 11, 229. Beech, W.F., "Fibre Reactive Dyes", 210, 233, Logos Press, London (1970). British Patent, 1, 403, 297 (1973).

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

12 Recent Developments in Grafting of Monomers to Wool Keratin Using U V and γ-Radiation JOHN L. GARNETT The University of New South Wales, Kensington, NSW, Australia 2033 JOHN D. LEEDER C.S.I.R.O. Division of Textile Industry, Belmont, Victoria, Australia 3216 The application of syntheti i potentiall of great importance fo properties of the fibre (1-6). For graft copolymerization of vinyl monomers, radiation-induced techniques utilizing ionizing radiation and, more recently, UV have attracted considerable research attention because of their potential to reduce effluent problems and lower costs of chemicals and energy. Ionizing radiation copolymerization has been studied by a number of workers (1, 6-10). However, radiation doses to achieve satisfactory grafting have generally been relatively high, thus reducing the possibility of a practical treatment. Recently the radiation-induced grafting of acrylonitrile to wool in the presence of vinyl sulfonyl dyes was reported (11). Photochemical initiation for copolymerization to wool has also been studied, both in the vapour phase (12) and in solution, essentially by the mutual irradiation method (10,13,14). In the ionizing radiation procedure it is advantageous to increase the degree of conversion of monomer to (grafted) polymer, and to reduce significantly the irradiation time, the total dose received by the trunk polymer, and the formation of homopolymer, if the mutual irradiation pro­ cedure (the most versatile method) is to be commercially viable. In addition it is important to consider grafting systems where the organic solvent has been replaced by an aqueous medium. It is the purpose of this paper to discuss recent advances in this field, with particular regard to practical development of UV and ionizing radiation processes for grafting vinyl monomers to wool. Experimental Grafting Procedures The ionizing and photochemical-radiation equipment and pro­ cedures used for the wool work were essentially similar to those described at this Conference for grafting to cellulose (15). The wool used was either a light-weight (150 gm m~) plain weave fabric made from 21μ diameter Merino wool fibres, or loose wool (in "top" form) from the same source. Small squares of fibre 2

197

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

198

TEXTILE

AND

PAPER

CHEMISTRY

AND

TECHNOLOGY

G

bundles o f 0.4-0.5 g were weighed a f t e r e q u i l i b r a t i o n at 23 C, 65% RH f o r at l e a s t 24 hours. For the emulsion experiments, emulsions o f e t h y l a e r y l a t e were prepared by v i g o r o u s l y shaking monomer, water and e m u l s i f y i n g agent u n t i l a s t a b l e emulsion was formed. For a 50% emulsion, t h i s r e q u i r e d about 30 seconds shaking. For lower concentrations o f monomer, i t was p r e f e r a b l e to d i l u t e the 50% emulsion. For the UV work, two sources were used, namely a P h i l i p s 90W high-pressure lamp (15) and a 6-inch (200W/inch) Hanovia h i g h pressure lamp. For the padding technique wool samples were squeezed with an equal weight o f l i q u o r i n a device designed t o simulate a pad mangle. A f t e r a l l treatments, samples were washed i n hot methanol to remove unreacted monomer, then e x h a u s t i v e l y e x t r a c t e d to remove homopolymer Q). A c i d Catalyzed G r a f t i n Recent work has shown that mineral acids are capable o f c a t a l y z i n g g r a f t i n g o f monomers to wool (16). Further data on a c i d c a t a l y s i s are presented here as a prelude to r e s u l t s f o r radiation grafting. These r e s u l t s a c t u a l l y represent c o n t r o l experiments f o r the a c i d enhancement o f r a d i a t i o n g r a f t i n g to be discussed i n one o f the f o l l o w i n g s e c t i o n s . The r a t e o f a c i d - c a t a l y z e d copolymerization i n wool (Table 1) i s very much f a s t e r and more uniform than i n other common polymers TABLE 1.

G r a f t i n g o f Styrene to Wool i n A c i d i f i e d S o l u t i o n at 43°C α 50% Styrene

Time (hours)

% Graft

1.0 2.0 3.0 5.0 7.0 14.0 32.5 72 a

0.2N methanolic HN0 to wool r a t i o used.

4 8 12 26 46 44 58 68 3

Methanol

75% Styrene % Graft 6 12 20 35 45 242 4850

-

s o l u t i o n i n a i r and " i n f i n i t e "

liquor

such as c e l l u l o s e and the p o l y o l e f i n s (16,17). In Table 1, t y p i c a l r e s u l t s are shown f o r the g r a f t i n g o f styrene to wool i n the presence o f d i l u t e n i t r i c a c i d and a t y p i c a l s w e l l i n g solvent such as methanol. The g r a f t i n g r a t e i s i n c r e a s e d remarkably by i n c r e a s i n g the monomer c o n c e n t r a t i o n (1,16,17) or the temperature QiLiiZ)· No i n d u c t i o n p e r i o d i s observed but g r a f t i n g becomes

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

12.

GARNETT

AND

Radiation

LEEDER

Grafting

of Monomers

to Wool

199

extremely r a p i d a f t e r a c e r t a i n l e v e l o f copolymerization has been a t t a i n e d . A i r exerts n e g l i g i b l e e f f e c t on the r e a c t i o n . The p h y s i c a l form o f the wool a f f e c t s the g r a f t i n g r a t e ; loose wool f i b r e s and wool powder g r a f t more r a p i d l y than wool f a b r i c . Very h i g h l y g r a f t e d f i b r e s i n c r e a s e t h e i r p h y s i c a l dimensions s e v e r a l times, and e v e n t u a l l y b u r s t at around 5000% g r a f t . Extremely slow g r a f t i n g i s observed over long p e r i o d s i n the absence o f a c i d . Homopolymer formation, as evidenced by an i n ­ crease i n v i s c o s i t y , i s only s i g n i f i c a n t at 80% styrene concen­ trations; at lower monomer c o n c e n t r a t i o n s , even at 2500% g r a f t , the v i s c o s i t y o f the supernatant l i q u i d does not change s i g n i f i c a n t l y (17). Changing the a c i d used f o r c a t a l y s i s has a profound e f f e c t on the g r a f t i n g r e a c t i o n followed by s u l f u r i c a c i reached at the highest styrene c o n c e n t r a t i o n . Increase i n temperature has a dramatic e f f e c t on the g r a f t i n g , as shown by the behaviour with s u l f u r i c a c i d at 50°C (Table I I ) . TABLE I I .

E f f e c t o f A c i d S t r u c t u r e i n Catalyzed G r a f t i n g o f Styrene to Wool a

%

% Styrene H2SO4

20 40 60 80 90

HC1

7 \Φ 8 57^ 15 150& 26 900& 32e 2210&

6 6 7 ηο 1

G

r

a

f

t

i

HNO3

28 121 1750 2630 3050

n

A

c

i

d

HC10i>

7 8 12 20^ 19
HCOOH

CH3COOH

2 1 0 3 44

1 1 1 1 1

0.2N methanolic a c i d s o l u t i o n s ; 10 days r e a c t i o n i n a i r at 23°C except f o r formic and a c e t i c acids (0.1N f o r 4 days) and 0.2N

methanolic Η 5 ( Η ; 2

r e a c t i o n time 45 hours at 50°C.

Phase s e p a r a t i o n . Even at 23°C, i f the r e a c t i o n i s allowed t o proceed f o r very long (e.g. 400 h r s ) , 80% styrene i n methanolic ^ S O i * can y i e l d g r a f t s of the order o f 2000%. When methanol i s r e p l a c e d by other p o l a r solvents such as ethanol, dimethyl s u l f o x i d e and dimethyl formamide, s i m i l a r r e s u l t s to those shown i n Tables I and II are obtained (17), accentuating the r o l e o f s w e l l i n g s o l v e n t s i n t h i s copolymerization. When the a c i d c a t a l y z e d process i s a p p l i e d t o the copolymer­ i z a t i o n o f monomers other than styrene, there i s e i t h e r l i t t l e g r a f t i n g , or severe homopolymer formation. Thus, with e t h y l a c r y l a t e , although some g r a f t i n g i s achieved the supernatant i s v i r t u a l l y completely g e l l e d a f t e r 24 hours at 43°C, while a c r y l o n i t r i l e gave n e i t h e r g r a f t i n g nor homopolymer formation. Methyl

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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methacrylate e x h i b i t s both p r o p e r t i e s shown by these two monomers i n t h a t , at 20% concentration there i s l i t t l e g r a f t i n g and very l i t t l e homopolymer formation (17), whereas at higher monomer concentrations a p p r e c i a b l e copolymer and homopolymer f o r ­ mation i s observed (Table I I I ) . This general p a t t e r n of TABLE I I I .

A c i d Catalyzed G r a f t i n g o f Various Monomers to Wool^

Monomer

Graft

Styrene D i v i n y l benzene α-Methyl styrene 4 - t - b u t y l styrene Acrylic acid Ethyl aerylate A l l y l aerylate Aery1amide Ethylene dimethacrylate V i n y l acetate Isoprene V i n y l e t h y l ether Methyl methacrylate^

(%)

Homopolymer

66 50 10

No No Yes

8 9 8 25 13 17 8 90

Yes Yes No Yes No No No Yes

50% monomer i n 0.2N methanolic HN0 ; r e a c t e d at 43°C f o r 62 hrs i n a i r ; l i q u o r to wool r a t i o 50:1; wool f a b r i c used except i n b. 3

u

0.1N

methanolic HN0 ; 3

43°C f o r 18.5 hrs i n a i r ;

loose wool.

behaviour occurs with a c i d c a t a l y z e d g r a f t i n g o f a range o f unsaturated monomers (Table I I I ) . Considering the e x c e l l e n t s p e c i f i c i t y o f styrene f o r copolymer formation without accompany­ ing homopolymerization, i t i s perhaps s u r p r i s i n g that some styrene d e r i v a t i v e s tend towards homopolymerization. However, i t must be s t r e s s e d that the r e s u l t s i n Table I I I were obtained under a standard set o f c o n d i t i o n s . Thus, although these r e s u l t s g i v e an i n d i c a t i o n o f the comparative r e a c t i v i t i e s and s p e c i f i c i t i e s o f the monomers s t u d i e d , i t i s p o s s i b l e t h a t f u r t h e r work on any o f these systems could y i e l d c o n d i t i o n s where there i s l e s s homopolymerization and/or increased g r a f t i n g . Mechanism o f A c i d Catalyzed G r a f t i n g . The preceding obser­ vations on copolymer/homopolymer formation, p l u s s t u d i e s u s i n g e l e c t r o n microscopy (17) i n d i c a t e that a c i d c a t a l y z e d polymeriz­ a t i o n can s p e c i f i c a l l y occur w i t h i n the wool s t r u c t u r e , p a r t i c u l a r l y with styrene. Free r a d i c a l scavengers have been found to i n h i b i t copolymerization (17). G r a f t i n g was only e f f e c t ­ ive i n p o l a r s o l v e n t s capable o f s w e l l i n g the trunk polymer. It has r e c e n t l y been shown (18) that e t h y l a e r y l a t e g r a f t s "spontaneously" to wool from aqueous emulsion, but a long

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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i n d u c t i o n p e r i o d i s a s s o c i a t e d with the r e a c t i o n . In the present a c i d system, no i n d u c t i o n p e r i o d i s observed even with e t h y l a c r y l a t e , but the g r a f t i n g r e a c t i o n becomes extremely r a p i d a f t e r a c e r t a i n l e v e l o f copolymerization has occurred. T h i s change i n r a t e probably c o i n c i d e s with a change from a d i f f u s i o n - c o n t r o l l e d r e a c t i o n to one that i s e s s e n t i a l l y a bulk r e a c t i o n and may c o r r e l a t e with rupture o f h i s t o l o g i c a l or macromolecular regions w i t h i n the wool f i b r e s . T h i s type o f breakdown would be c o n s i s tent with the mechanochemical theory o f g r a f t i n g discussed by Stannett and coworkers (18). Styrene Comonomer Studies U t i l i z i n g Acid-Catalyzed G r a f t i n g . The foregoing r e s u l t s have shown that styrene g r a f t s to wool with l i t t l e tendency to homopolymerize wool/polymer systems hav Lipson and Speakman (19), although extensive commercial use has not yet been found f o r such copolymers. For maximum u t i l i z a t i o n of such a copolymerization technique, i t should p r e f e r a b l y be a p p l i c a b l e to monomers other than styrene; thus the technique must overcome problems o f homopolymer formation and/or f a i l u r e to g r a f t to the trunk polymer. The use o f comonomers, i n which one of the monomers i s styrene, has been found, during the present work, to decrease the tendency o f other monomers to homopolymerize and at the same time to i n c r e a s e g r a f t i n g e f f i c i e n c y . When methyl methacrylate i s g r a f t e d to wool u s i n g the combined a c i d catalyzed/styrene comonomer technique (Table IV), v i r t u a l l y no TABLE IV.

Acid-Catalyzed G r a f t i n g o f Methyl Methacrylate and A c r y l o n i t r i l e to Wool Using Styrene Comonomer Technique a

Styrene

10 20 20 30 40 40 10 20 30 40

(%)

Comonomer

10 20

MMA MMA

30 40

MMA MMA

10 20 30 40

AC AC AC AC

(%)&

G r a f t Wo

20 116 12 800 1685 154 3 4 10 4400

(2) (50)

Solution Viscosity No change No change

(120) (80)

70-100 700-800

(2) (0) (3) (4)

No No No No

change change change change

a

0.1N methanolic HN0 , r e a c t e d at 43°C f o r 18.5 hrs i n a i r ; l i q u o r to wool r a t i o 50:1; loose wool used. b MMA = methyl methacrylate; AC = a c r y l o n i t r i l e . 2 Figures i n brackets are g r a f t s obtained f o r MMA or AC alone. 3

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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homopolymer i s observed at low styrene/methyl methacrylate monomer c o n c e n t r a t i o n s , and g r a f t i n g i s s i g n i f i c a n t . As the mixed monomer c o n c e n t r a t i o n i s i n c r e a s e d , considerable g r a f t i n g occurs (800%) accompanied by some homopolymer formation. The r e s u l t s o f a c i d c a t a l y z e d g r a f t i n g o f a c r y l o n i t r i l e using the styrene comonomer technique (Table IV) are even more s i g n i f i c a n t , s i n c e g r a f t i n g (4400%) i s now achieved with v i r t u a l l y no homopolymer formation. A s i m i l a r r e d u c t i o n i n homopolymeriza t i o n i s observed with the g r a f t i n g o f e t h y l a c r y l a t e (Table V). TABLE V.

Styrene

67.5 62.5 37.5 12.5 7.5 75

A c i d Catalyzed G r a f t i n g o f E t h y l A c r y l a t e to Wool Using Styrene Comonomer Technique & (%)

Ethyl Acrylat

7.5 12.5 37.5 62.5 67.5 0

8.8 11.3 10.3 9.5 9.4 35.0

0.116 0.167 0.103 0.085 0.024

7.413 4.457 1.435 0.561 0.366

0.2N methanolic r ^ S O i * , r e a c t e d at 43°C f o r 5 hrs i n a i r ; l i q u o r to wool r a t i o 25:1; wool f a b r i c used. S = styrene, EA = e t h y l a c r y l a t e . copolymer equation (20).

C a l c u l a t e d from

classical

A d d i t i o n a l important information was obtained i n t h i s s e r i e s s i n c e styrene l a b e l l e d with t r i t i u m (17) was used to estimate a c c u r a t e l y the percentage o f each o f the g r a f t e d monomers. The data show that even at r e l a t i v e l y short conversion times (5 hours) with g r a f t s of approximately 10%, the more p o l a r e t h y l a c r y l a t e i s the monomer predominantly g r a f t e d , most o f the o r i g i n a l styrene remaining unreacted i n s o l u t i o n . Further, l i t t l e homopolymer i s present i n the r e s i d u a l g r a f t i n g s o l u t i o n s from the styrene comonomer experiments a f t e r r e a c t i o n f o r a number o f hours at 44°C. With methyl methacrylate-styrene and a c r y l o n i t r i l e - s t y r e n e i n methanol s o l u t i o n s g r a f t s o f up to 4400% were r e a d i l y achieved. T h i s corresponded to complete g r a f t i n g o f the monomers present i n i t i a l l y without any homopolymer being formed. In a d d i t i o n to reducing homopolymer formation i n the g r a f t i n g of methyl methacrylate and a c r y l o n i t r i l e , the presence of styrene i n the comonomer mixture i n c r e a s e s the magnitude o f the g r a f t at a l l concentrations o f monomer mixtures s t u d i e d . T h i s percentage increase i n g r a f t i s very much higher f o r both methyl methacrylate and a c r y l o n i t r i l e at the high monomer mixture c o n c e n t r a t i o n s , p a r t i c u l a r l y above 50% v/v. I n c l u s i o n o f a second monomer (ethyl a c r y l a t e ) r e t a r d s the r a t e at which the mixture (ethyl a c r y l a t e /

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styrene) g r a f t s r e l a t i v e to styrene alone. Mechanism o f A c i d Catalyzed Styrene Comonomer G r a f t i n g . An important f e a t u r e m e c h a n i s t i c a l l y o f the present data (Table V), p a r t i c u l a r l y when e t h y l a c r y l a t e i s used as the second monomer at concentrations o f 75% t o t a l monomer s o l u t i o n , i s t h a t the percent g r a f t i s v i r t u a l l y independent o f the r a t i o o f e t h y l a c r y l a t e to styrene. The f a c t t h a t the observed r a t i o o f s t y r e n e / e t h y l a c r y l a t e i n Table V i s s i g n i f i c a n t l y l e s s than the value c a l c u l a t e d from the copolymerization equation i s c o n s i s t e n t with the data o f Odian and co-workers f o r r a d i a t i o n copolymerization to polyethylene (20), where higher percentages o f the more p o l a r monomer are i n c o r p o r a t e d than p r e d i c t e d by the copolymerization equation. T h i s competitiv inhibitio f th styren graft suggests that the monome i s more s t r o n g l y adsorbe grafting polymer. The presence o f p o l a r s o l v e n t s , through s w e l l i n g , make these s i t e s more a c c e s s i b l e to g r a f t i n g monomer. In the presence o f mineral a c i d s , conformations may be a l t e r e d more d r a s t i c a l l y by the breaking o f s a l t bridges and other l a b i l e bonds, a l l o w i n g r a p i d s w e l l i n g with the "mechanical" production (18) o f f r e e r a d i c a l s which become the a c t u a l g r a f t i n g s i t e s . Again, i t should be noted t h a t s w e l l i n g alone does not e x p l a i n these r e s u l t s , s i n c e formic a c i d i s not as e f f e c t i v e as n i t r i c a c i d as a polymeri z a t i o n c a t a l y s t (17). R a d i a t i o n G r a f t i n g o f Monomers A d e t a i l e d study has been made o f the e f f e c t o f r a d i a t i o n dose r a t e and t o t a l dose on the g r a f t i n g o f monomers to wool by the mutual i r r a d i a t i o n technique (1,17). No Trommsdorff peak i s evident at lower concentrations o f monomer as there i s with other trunk polymers such as c e l l u l o s e (15,21) and polypropylene (22). The s i g n i f i c a n t f e a t u r e o f t h i s e a r l i e r work i s t h a t , at a l l styrene concentrations, copolymer formation decreases with i n c r e a s i n g dose r a t e , f o r the same t o t a l dose. Table VI shows that g r a f t i n g i s -more e f f e c t i v e from s o l v e n t s which are small p o l a r molecules ( p a r t i c u l a r l y methanol) than from s o l v e n t s which are large and/or non-polar. Thus, even the most e f f e c t i v e non-polar s o l v e n t , hexane, gave 14% g r a f t from 60% styrene s o l u t i o n a f t e r 10 Mrads of r a d i a t i o n , w h i l s t only 0.2 Mrads was r e q u i r e d to g r a f t 28% styrene from 60% styrene s o l u t i o n i n methanol. By c o n t r a s t with styrene the f o l l o w i n g monomers achieve the r e l a t i v e l y low g r a f t shown i n parentheses a f t e r i r r a d i a t i o n at 0.1 Mrad/hr to t o t a l doses o f 5 Mrads: isoprene (66%), a c r o l e i n (23%), e t h y l a c r y l a t e (31%) and g l y c i d y l a c r y l a t e (0.2%). Mechanism o f R a d i a t i o n G r a f t i n g . I f an i n h i b i t o r such as t - b u t y l c a t e c h o l i s added to e i t h e r styrene or e t h y l a c r y l a t e i n methanol, r a d i a t i o n - g r a f t i n g i s reduced (Table V I I ) , confirming

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TABLE VI.

R a d i a t i o n G r a f t i n g o f Styrene to Wool i n Various Solvents a

Graft

(%) i n Solvent

Methanol

Ethanol

Butanol

Dimethyl Formamide

8 27 28 33

7 6 6 4

3 2 4 3

6 4 3 2

20 4

°2> 60^ 80 100

Dimethyl Dioxan Sulfoxide 12 13 8 6

3 4 1 4

CD

Y-Radiation dose 0.2 Mra I r r a d i a t i o n o f 60% styrene i n non-swelling hexane at 0.1 Mrad/hr to 10 Mrads gave 14% g r a f t . TABLE V I I .

R a d i a t i o n G r a f t i n g o f Styrene and E t h y l A c r y l a t e i n Presence o f t - B u t y l Catechol a

t - B u t y l Catechol

Graft

(%) Styrene

0.0 0.01 0.1 0.5

152 109 17 2

(%) Ethyl Acrylate 22 19 14 4

60% (v/v) monomer i n methanol. Styrene i r r a d i a t e d i n a i r to 0.5 Mrads. E t h y l a c r y l a t e i r r a d i a t e d under n i t r o g e n to 0.2 Mrads. Dose r a t e 0.1 Mrad /hour. t h a t the predominant mechanism f o r the g r a f t i n g i s a f r e e - r a d i c a l process. However, wool i s a r e l a t i v e l y p o l a r trunk polymer; i o n i c and energy t r a n s f e r processes are known to occur i n i o n i z i n g r a d i a t i o n systems; thus some c o n t r i b u t i o n from these a l t e r n a t i v e processes would be expected i n the g r a f t i n g r e a c t i o n . R a d i c a l s , i.e. g r a f t i n g s i t e s , form i n wool during exposure to r a d i a t i o n (6,7,23). Monomers can then copolymerize at these s i t e s v i a c h a r g e - t r a n s f e r intermediate formation as proposed e a r l i e r f o r wool (1) and c e l l u l o s e (1,15,24). The presence o f s w e l l i n g solvents i s o b v i o u s l y advantageous f o r the mutual i r r a d i a t i o n technique s i n c e s w e l l i n g o f the trunk polymer i s necessary t o allow the monomers access to the f r e e r a d i c a l s i t e s w i t h i n the wool s t r u c t u r e . Again some mechanism other than s w e l l i n g by the solvent must be o p e r a t i v e - methanol and ethanol s w e l l wool to the same extent (25), w h i l s t dimethyl s u l f o x i d e and dimethyl formamide would be expected to s w e l l wool much more than the a l c o h o l s (26) yet extent o f g r a f t i n g v a r i e s c o n s i d e r a b l y . D i f f e r e n t a c c e s s i b i l i t i e s to the v a r i o u s h i s t o c h e m i c a l regions o f the f i b r e ,

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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together with d i f f e r e n t p r o p e n s i t i e s f o r f r e e r a d i c a l formation i n these r e g i o n s , may w e l l be an i n f l u e n c i n g f a c t o r . Styrene Comonomer Technique i n R a d i a t i o n G r a f t i n g . The e s s e n t i a l problem with r a d i a t i o n g r a f t i n g of monomers other than styrene to wool i s that g e n e r a l l y severe homopolymer formation accompanies g r a f t i n g , and v i r t u a l l y precludes use of the technique. However, i f styrene i s added to the r a d i a t i o n g r a f t i n g system (e.g. e t h y l a c r y l a t e ) , homopolymer formation i s overcome and f i n i t e g r a f t i n g i s achieved (Table V I I I ) . In a d d i t i o n , even at high e t h y l a c r y l a t e / s t y r e n e r a t i o s (5:1), the g r a f t predominantly c o n s i s t s of e t h y l a c r y l a t e (74%). These data were obtained u s i n g a novel procedure i n v o l v i n g t r i t i u m l a b e l l e d styrene (17). TABLE V I I I .

Dose (Mrads) 2.7 9.5 2.1

Radiation Wool Using Styrene Comonomer Technique Styrene

S/EA

b

Graft

(%)

Ethyl Acrylate

(%)

Found

Calc.

37.5 37.5 12.5

37.5 37.5 62.5

2.7 9.5 2.1

0.40 0.87 0.26

1.435 1.435 0.557

Liquor to wool r a t i o 25:1. 0.1 Mrad/hour.

Wool f a b r i c used.

S = styrene, EA = e t h y l a c r y l a t e . copolymer equation (20). A c i d Catalyzed R a d i a t i o n

Calculated

Radiation from c l a s s i c a l

Grafting

In previous p r e l i m i n a r y work (17), the presence of a c i d was shown to enhance r a d i a t i o n g r a f t i n g o f styrene i n methanol to wool i n contrast to the e f f e c t s f o r a c i d alone. These data showed that s u l f u r i c and p e r c h l o r i c acids were b e t t e r c a t a l y s t s than n i t r i c a c i d when combined with the mutual i r r a d i a t i o n technique. Table IX shows that the e f f e c t of solvent on a c i d - c a t a l y z e d r a d i a t i o n g r a f t i n g to wool follows a s i m i l a r trend to that f o r r a d i a t i o n without a c i d (Table V I ) . Again, the longer chain a l c o h o l s are l e s s e f f e c t i v e than methanol; with butanol, there appears to be no enhancement of g r a f t i n g by the presence of a c i d . The most remarkable r e s u l t i n Table IX i s that obtained f o r dimethyl s u l f o x i d e , which now becomes the most a c t i v e solvent o f those studied f o r t h i s combination of g r a f t i n g c o n d i t i o n s . Very large amounts o f g r a f t i n g occur, with a Trommsdorff peak at 352% f o r the 80% styrene s o l u t i o n , at a t o t a l dose of only 0.2 Mrads. Unfortunately, when r a d i a t i o n was combined with a c i d c a t a l y s i s f o r the g r a f t i n g o f a range o f monomers other than styrene, homop o l y m e r i z a t i o n i n v a r i a b l y masked any increases i n r a t e or extent

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of copolymer formation. Again t h i s was with p o l y f u n c t i o n a l a c r y l a t e monomers.

particularly

noticeable

Mechanism o f A c i d Enhanced Radiation G r a f t i n g . The a c i d enhancement, when styrene i n p o l a r solvents i s r a d i a t i o n g r a f t e d to wool, i s broadly analogous to the a c i d enhancement found when r a d i a t i o n copolymerizing to other trunk polymers such as c e l l u l o s e (27) and the p o l y o l e f i n s (22). However, with wool, the e f f e c t i s more complicated because wool i s also capable of an extensive simple a c i d catalyzed g r a f t i n g r e a c t i o n as p r e v i o u s l y discussed. The a c i d catalyzed copolymerization i s very much slower than radiation grafting; however, once the r a d i c a l s i t e s are formed by impinging r a d i a t i o n , a c i d catalyzed g r a f t i n g can occur at a much faster rate. TABLE IX.

Acid-Catalyzed Radiation G r a f t i n g o f Styrene to Wool i n Various Solvents a

Styrene (%) 20 40 60 80 90

Graft

Methanol 38 58 73 90

(%) i n Solvent^ Dimethyl Dimethyl Butanol Formamide Sulfoxide

Ethanol

(8) (27) (28) (33)

H 14 14 17 16

-

(4) (7) (7) (4) (5)

3 3 3 3 3

(3) (2) (4) (3) (5)

20 24 12 7 4

(6) (4) (2) (2) (4)

47 103 176 352 65

(12) (13) (8) (5) (7)

R a d i a t i o n dose 0.2 Mrads at 0.025 Mrad/hour; 0.2N H S0 ^ used f o r a c i d c a t a l y s i s . Figures i n brackets are f o r r a d i a t i o n g r a f t i n g without a c i d . 2

k

A l t e r n a t i v e l y , the a c i d enhancement i n r a d i a t i o n g r a f t i n g to wool may be a r a d i a t i o n chemistry phenomenon as proposed f o r c e l l u l o s e (15,27,28) and the p o l y o l e f i n s (22). With the l a t t e r two trunk polymers, the a v a i l a b l e evidence suggests that r a d i a t i o n g r a f t i n g to these m a t e r i a l s i s associated with, and a s s i s t e d by, H atom formation (i.e. G(H) y i e l d s ) . In terms of t h i s theory, any procedure f o r i n c r e a s i n g G(H) i n the r a d i o l y t i c system should a l s o assist radiation grafting. In the r a d i a t i o n chemistry of solvent methanol (29-31), a d d i t i o n of mineral a c i d increases G(H) y i e l d s through secondary e l e c t r o n capture, as i n Equation 1. Thus, i n a H

+

+

e

H

(1)

r a d i a t i o n g r a f t i n g system containing styrene/methanol/wool, a d d i t i o n o f a c i d should increase G(H) y i e l d s and a l s o enhance g r a f t i n g , as observed. However, at t h i s time i t i s not p o s s i b l e to separate the c o n t r i b u t i o n of simple a c i d c a t a l y s i s and r a d i a t i o n to the o v e r a l l g r a f t i n g mechanism. In current studies i t i s hoped to achieve t h i s aim.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

12.

GARNETT

AND

LEEDER

Radiation

Grafting

of Monomers

to Wool

207

A c i d Enhancement o f Styrene Gomonomer Technique i n R a d i a t i o n Grafting. When the styrene conomomer technique i s a p p l i e d to the preceding system o f a c i d - c a t a l y s i s combined with r a d i a t i o n g r a f t i n g , a l a r g e enhancement i n copolymerization i s achieved f o r the same r a d i a t i o n dose (Table X). Thus with e t h y l a c r y l a t e / styrene mixtures at 0.4 Mrads dose o f gamma r a d i a t i o n , i n c l u s i o n TABLE X.

Styrene (*) 37.5 37.5 37.5 37.5 37.5 50 12.5

A c i d Enhancement o f R a d i a t i o n G r a f t i n g o f E t h y l A c r y l a t e to Wool u s i n g the Styrene Comonomer Technique' Ethyl Acrylate (%)

Dose (Mrad)

37.5 37.5 37.5 37.5 37.5 25 62.5

0.1 0.2 0.4 0.2 0.2

S/EA

h Graft^

3

Found*

(%)

13 28 80 40 18

(2) (3) (10) (2)

0.17 0.74 0.87 1.40 0.13

Calc.

d

1.44 1.44 1.44 2.25 0.56

G r a f t i n g s o l u t i o n s (75% t o t a l monomer) 0.2N methanolic H a S O i * . Liquor to wool r a t i o 25:1. Wool f a b r i c used. R a d i a t i o n dose ^ r a t e 0.1 Mrad/hour. Values i n brackets are f o r r a d i a t i o n and comonomer technique without a c i d . ^ Estimated by t r i t i u m - l a b e l l i n g technique (16). C a l c u l a t e d from the c l a s s i c a l copolymer equation (20). A c i d - c a t a l y z e d comonomer technique (no r a d i a t i o n ) at 43°C f o r 4 hours (i.e. e q u i v a l e n t t o longest r a d i a t i o n time i n the T a b l e ) . of 0.2N H2SO4 leads to an almost t e n f o l d i n c r e a s e i n g r a f t with 75% t o t a l monomer c o n c e n t r a t i o n i n methanol. At a l l e t h y l a c r y l a t e / s t y r e n e r a t i o s the g r a f t s c o n t a i n more e t h y l a c r y l a t e monomer than i s p r e d i c t e d from theory. A l l g r a f t i n g y i e l d s are higher than the simple a c i d c a t a l y z e d blank (7%) which was a r e a c t i o n c a r r i e d out f o r 4 hours at 43°C with a c i d only, i . e . the same time as f o r the h i g h e s t r a d i a t i o n dose sample where the corresponding g r a f t was 80%. Methyl methacrylate i s one monomer which i s d i f f i c u l t to g r a f t e f f i c i e n t l y to wool without the comonomer technique because o f competing homopolymer formation. The data i n Table XI show the g r a f t i n g o f methyl methacrylate u s i n g four d i f f e r e n t r a d i a t i o n systems, i . e . g r a f t i n g with r a d i a t i o n , r a d i a t i o n with a c i d , r a d i a t i o n with styrene comonomer technique, and f i n a l l y a c i d enhancement o f the r a d i a t i o n / s t y r e n e comonomer procedure. The s i g n i f i c a n t advantages o f the l a s t technique are apparent, v i r t u a l l y no homopolymer being detected i n any o f the runs i n the l a s t MMA column o f the t a b l e . Analogous data f o r the a c r y l o n i t r i l e / m e t h a n o l monomer system are a l s o shown i n Table XI.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

208

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

TABLE XI.

A c i d Enhancement i n R a d i a t i o n G r a f t i n g o f Methyl Methacrylate (MMA) t o Wool u s i n g Styrene (S) Comonomer Technique a

Graft

Monomer (%)

MMA

10 30 50 70 90

3 2 3 7 3

+

MMA+H 7 6 51& 78& 20b

+

S/MMA S/MMA+H (1/1) (1/1)* 3 21 31 18

7 60 92 91 69

72

(%) AC 3 0 2 4 3

AC+H 4 4 5 3 b

+

S/AC S/AC + H (1/1) (1/1) 4 12 37& 42b 2Φ

+

10

94C 1822 2142 e

" R a d i a t i o n dose 0.2 ^ f a b r i c used with 0.2N HN0 . Supernatant v i s c o u s , i n d i c a t i n g s i g n i f i c a n t homopolymerization. ^ S l i g h t l y v i s c o u s supernatant. No v i s c o s i t y i n c r e a s e i n supernatant f o r any o f these samples Heavy g r a f t , supernatant h i g h v i s c o s i t y . 3

S i m i l a r conclusions can be drawn from these r e s u l t s , although even using the styrene comonomer technique with a c r y l o n i t r i l e p l u s a c i d enhancement, some homopolymer was present i n the supernatant liquid. The a c i d enhanced styrene comonomer r a d i a t i o n g r a f t i n g technique has a l s o been a p p l i e d t o the copolymerization o f other monomers (17). In a l l cases use o f the combined techniques was advantageous f o r e i t h e r i n c r e a s i n g g r a f t i n g e f f i c i e n c y and/or reducing homopolymerization. T h i s i s o f p o t e n t i a l value, e.g. with p o l y f u n c t i o n a l monomers such as g l y c i d y l a c r y l a t e , which are u s u a l l y d i f f i c u l t t o g r a f t without accompanying homopolymer formation. Mechanism o f A c i d Enhancement o f Styrene Comonomer R a d i a t i o n Grafting. The a c i d enhancement e f f e c t o f the styrene comonomer r a d i a t i o n process i s c o n s i s t e n t with the a c c e l e r a t i n g e f f e c t o f mineral a c i d i n r a d i a t i o n g r a f t i n g o f styrene t o wool d i s c u s s e d e a r l i e r i n t h i s paper. Monomers other than styrene could only be g r a f t e d t o wool i n the presence o f a c i d i f the styrene comonomer technique were used, s i n c e attempts t o g r a f t monomers alone, without styrene, r e s u l t e d i n predominant homopolymerization o r very l i t t l e copolymerization. A number o f mechanistic aspects o f the r a d i a t i o n comonomer procedure are s i m i l a r t o the simple a c i d c a t a l y z e d comonomer technique p r e v i o u s l y d i s c u s s e d . The data i n d i c a t e that the monomer other than styrene {e.g. e t h y l a c r y l a t e ) i s s t r o n g l y adsorbed t o the p r o t e i n chain a t the a c t i v e g r a f t i n g s i t e . In the f i r s t technique these s i t e s o r i g i n a t e from bond rupture by i o n i z i n g r a d i a t i o n , whereas i n the simple a c i d c a t a l y z e d process i t appears that mineral a c i d s a l t e r conformations, probably by breaking s a l t b r i d g e s and hydrogen bonds and a l l o w i n g s w e l l i n g

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

12.

GARNETT

AND

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Radiation

Grafting

of Monomers

to Wool

209

with the mechanical p r o d u c t i o n o f f r e e r a d i c a l s (18). The added presence o f p o l a r solvents then make these s i t e s (whether formed by r a d i a t i o n or simple acid) more a c c e s s i b l e by a l t e r i n g the conformation o f the p r o t e i n chain. However, the degree o f s w e l l i n g i s not the primary mechanism - some o f the a c i d / s o l v e n t systems i n t h i s study were not as e f f e c t i v e as other systems o f lower s w e l l i n g p o t e n t i a l . Presumably d i f f e r e n t i a l a c c e s s i b i l i t i e s and/or p o l y p e p t i d e chain p r o t o n a t i o n or s i d e group d i s s o c i a t i o n a l s o i n f l u e n c e the r e l a t i v e r a t e s and extent o f copolymerization and homopolymerization. The explanation o f the a c i d enhancement e f f e c t o f the r a d i a t i o n comonomer g r a f t i n g i s complicated by the f a c t that both a c i d and r a d i a t i o n can i n i t i a t e copolymerization independently. Although the simple a c i p e r i o d at room temperature r a d i a t i o n reduces t h i s i n d u c t i o n time, presumably because a d d i t i o n a l r a d i c a l s are formed by r a d i a t i o n . The presence o f a c i d would then expose these a d d i t i o n a l "radiâtion-formed" r a d i c a l s t o r e a c t i o n with monomer due to the mechanical s w e l l i n g e f f e c t o f the a c i d / s o l v e n t system. There i s a l s o the p u r e l y r a d i a t i o n chemistry explanation f o r the enhancement o f the r a d i a t i o n comonomer g r a f t i n g with wool. T h i s has p r e v i o u s l y been d i s c u s s e d i n t h i s paper to e x p l a i n the a c i d enhancement o f the simple r a d i a t i o n g r a f t i n g r e a c t i o n to wool. In g r a f t i n g to wool, i t i s probable t h a t the r a d i a t i o n chemistry mechanism and the mechanical s w e l l i n g mechanism both c o n t r i b u t e a p p r e c i a b l y to the a c i d enhancement o f the r a d i a t i o n copolymeriza t i o n ; with c e l l u l o s e and the p o l y o l e f i n s , simple a c i d - c a t a l y z e d g r a f t i n g i s i n s i g n i f i c a n t , and the r a d i a t i o n mechanism predominates. G r a f t i n g from Emulsions Using A c i d Plus R a d i a t i o n and Comonomer Techniques Stannett and co-workers (18) have p r e v i o u s l y shown that, i n an aqueous emulsion system, e t h y l a c r y l a t e g r a f t s t o wool, although a long i n d u c t i o n p e r i o d i s i n v o l v e d . In the present work, attempts are made to use d i s c o v e r i e s from the preceding s e c t i o n s to e l i m i n a t e the i n d u c t i o n p e r i o d by i n c l u d i n g a c i d and a styrene comonomer procedure. The data (Table XII) show that some g r a f t i n g of e t h y l a c r y l a t e occurs from emulsions a f t e r simply standing on contact at room temperature, i n agreement with Stannett et al.(18). In general, higher g r a f t s from emulsions are observed at 50°C than at 18°C.. The presence o f a c i d i n the emulsion i n c r e a s e s the graft, c o n s i s t e n t with the a c i d enhancement e f f e c t s already d i s c u s s e d i n g r a f t i n g styrene from methanolic s o l u t i o n . The presence o f styrene as a comonomer i n the emulsions enhances e t h y l a c r y l a t e g r a f t i n g when a c i d i s a l s o present, but not otherwise. Only a small advantage i s gained by u s i n g mutual i r r a d i a t i o n with emulsions, 10% conversion o f monomer to g r a f t copolymer being observed.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

210

TABLE XII.

G r a f t i n g o f E t h y l A c r y l a t e to Wool from Aqueous Emulsions with and without A c i d , R a d i a t i o n and Styrene Comonomer Techniques Graft

Emulsion*

2

(°) 50% 50% 25% 25%

EA + 4% X200 EA + 4% X200 EA/25% S+ 4% X200 EA/25% S + 4% X200

(%)

Τηττνη

18 50 18 50

No A c i d b

0.1N 2

1 3 1 2

1

h

H S0iT

8 9 6 9

O- ^ b

m

Q

9 11 7 29

0.1N Λ Ά No A c i d H S 0 ^

AT

2

3

5

3

5

a

EA = e t h y l a c r y l a t e ; e m u l s i f y i n g agent (Roh , with water. Contact time 18 hours; l i q u o r to wool r a t i o 20:1; no r a d i a t i o n . ° With r a d i a t i o n o f t o t a l dose 0.1 Mrad, dose-rate 0.1 Mrad/hour in air. Padded to give liquor/wool r a t i o o f 1:1.

P r e - I r r a d i a t i o n Studies o f G r a f t i n g . In t h i s p r o c e s s , gamma r a d i a t i o n creates f r e e r a d i c a l s at v a r i o u s s i t e s i n the wool. These s i t e s can then r e a c t with monomer from the emulsion or s o l v e n t , i f the wool has swollen s u f f i c i e n t l y to enable d i f f u s i o n of monomer to the r a d i c a l s i t e . Figure 1 shows the e f f e c t o f t o t a l p r e - i r r a d i a t i o n dose on the wool g r a f t when i r r a d i a t i o n o f the wool i s followed by padding, under n i t r o g e n , o f an equal weight o f emulsion c o n t a i n i n g e t h y l a c r y l a t e . Copolymerization i n c r e a s e s markedly w i t h t o t a l dose. Above 2 Megarads the wool begins to yellow s l i g h t l y due to the onset o f degradation. Doser a t e s o f up to 4.5 Mrads/hour had l i t t l e e f f e c t on percentage graft. E x t r a c t i o n was used to terminate f u r t h e r g r a f t i n g by removing unreacted monomer, when the r e q u i r e d r e a c t i o n time had expired. The time r e q u i r e d f o r complete r e a c t i o n i s about 40 minutes (Figure 2). In the f i r s t f i v e minutes g r a f t i n g occurs very r a p i d l y , but then becomes slower. The temperature o f the sample d u r i n g the time l a g a l s o a f f e c t s the g r a f t (Figure 3). Figure 4 shows the e f f e c t on the g r a f t o f exposing the p r e i r r a d i a t e d wool to a i r f o r v a r i o u s times before padding on o f emulsion, a probable n e c e s s i t y i n commercial a p p l i c a t i o n o f t h i s process. The reduced g r a f t i n g w i t h i n c r e a s i n g time o f exposure to a i r r e f l e c t s the decay o f f r e e r a d i c a l i n i t i a t i n g s i t e s i n a i r . F i g u r e 5 demonstrates the r o l e o f long l i q u o r r a t i o s on the grafting. Increasing the l i q u o r to wool r a t i o i n i t i a l l y i n c r e a s e s the amount o f a c r y l a t e g r a f t e d to p r e - i r r a d i a t e d wool u n t i l the l i q u o r to wool r a t i o i s about 4:1. However, the i n c r e a s e i n g r a f t i s l e s s than the p r o p o r t i o n a t e i n c r e a s e i n monomer present, so that there i s a f a l l i n the percentage conversion o f monomer to g r a f t copolymer. The e f f e c t o f monomer c o n c e n t r a t i o n on the g r a f t of e t h y l a c r y l a t e emulsions i s described i n F i g u r e 6. The

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

12.

GARNETT

A N D LEEDER

Radiation Grafting of Monomers to Wool

211

Total Dose (M rad) 1:1 1iquor:woo1; contact time 1 n r . ; monomer c o n c e n t r a t i o n 50% Figure 1. Effect of pre-irradiation dose on grafting of ethyl acryhte emulsion to wool

1:1 l i q u o r .-wool; 1 Mrad t o t a l dose; monomer c o n c e n t r a t i o n 50% Figure 2. Effect of contact grafting of ethyl acrylate irradiated wool

time on to pre-

ko

Dose rate 0.27 Mrad/hr. Dose rate O.J* Mrad/hr. 10

50

100

1:1 l i q u o r : w o o l ; 1 Mrad t o t a l dose; monomer c o n c e n t r a t i o n 50% Figure 3. Effect of temperature grafting of ethyl acrylate to irradiated wool

0

1

2

3

Exposure Time (hr.)

Temperature (°C)

on pre-

1:1 l i q u o r : w o o l ; 1 Mrad t o t a l dose; monomer concn. k0%\ contact time 1 h r . Figure 4. Effect of exposure to air of pre-irradiated wool on emulsion grafting of ethyl acrylate

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

212

0

5

10

15 20

25

Liquor:Woo1 R a t i o 1 M rad t o t a l dose at 0Λ Mrad/hr.; Honomer concn. 20%; contact time 1 h r . Figure 5. Effect of liquor ratio on emulsion grafting of ethyl acrylate to pre-irradiated wool

0

15

30

kS

60

Monomer Concentration

{%)

1 Mrad t o t a l dose at 0.*4 Mrad/hr.; 3:1 l i q u o r : w o o l ; contact time 1 h r . Figure 6. Effect of monomer con­ centration on emulsion grafting of ethyl acrylate to pre-irradiated wool

concentration o f monomer i n the emulsion i s l i m i t e d by emulsion s t a b i l i t y and v a r i e s with type o f e m u l s i f y i n g agent. The concen­ t r a t i o n l i m i t f o r which s t a b l e emulsions could be prepared was about 55% monomer, u s i n g 4% T r i t o n X200 as e m u l s i f y i n g agent. The r e s u l t s i n F i g u r e 6 show that the weight o f a c r y l a t e g r a f t e d to wool increases r a p i d l y up to 50% monomer; however, t h i s s t i l l represents a r e d u c t i o n i n the a c t u a l percentage conversion with i n c r e a s i n g monomer c o n c e n t r a t i o n . Mechanism o f P r e - I r r a d i a t i o n Emulsion G r a f t i n g . The e f f e c t s o f dose and dose-rate are c o n s i s t e n t w i t h the model system used, s i n c e an increase i n dose produces more r a d i c a l s i t e s on the trunk polymer, whereas a reduced dose-rate ( f o r a f i x e d t o t a l dose) achieves the same r e s u l t . A l i m i t i s reached where the concen­ t r a t i o n o f r a d i c a l s i s h i g h enough f o r s u b s t a n t i a l damage t o the molecular groups i n the wool t o occur, as evidenced by y e l l o w i n g at t o t a l doses i n excess o f 2 Mrad at 0.4 Mrad/hour. Although 70% o f the f i n a l g r a f t occurs i n the f i r s t f i v e minutes, about 40 minutes i s r e q u i r e d t o reach a maximum value. I t i s probable that f i v e minutes i s s u f f i c i e n t f o r the monomer i n the emulsion t o penetrate to a l l a c t i v e s i t e s and that the a d d i t i o n a l g r a f t i n g observed over long r e a c t i o n times represents the lengthening o f the chains formed at these a c t i v e s i t e s . Exposure t o a i r reduces the g r a f t , presumably by d e a c t i v a t i o n o f r a d i c a l s i t e s i n the presence o f oxygen (52). The copolymerizations i n Figures 1-6 were performed under n i t r o g e n , and pre-irradiâtion was c a r r i e d out i n vacuum.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

12.

GARNETT

AND

Radiation

LEEDER

Grafting

of Monomers

to Wool

213

An i n c r e a s e i n the l i q u o r t o wool r a t i o i n c r e a s e s the g r a f t from an emulsion c o n t a i n i n g 20% monomer, but the i n c r e a s e i s l e s s than the r e l a t i v e i n c r e a s e i n monomer weight present. This i s r e f l e c t e d by the drop i n the percentage conversion which i s s l i g h t l y under 50% at 1:1 l i q u o r to wool r a t i o . Photosensitized Grafting Replacement o f i o n i z i n g r a d i a t i o n with UV (Table XIII) leads to a p p r e c i a b l e g r a f t i n g o f styrene from methanol s o l u t i o n i n the presence o f a range o f s e n s i t i z e r s , both organic and i n o r g a n i c . Without s e n s i t i z e r , some g r a f t i n g to wool s t i l l occurs, and the presence o f a s w e l l i n g s o l v e n t such as methanol a s s i s t s the process. The photochemica s e n s i t i z e r , are c o n s i s t e n r e p o r t e d by other workers f o r the e f f e c t o f s w e l l i n g solvent i n photochemical g r a f t i n g t o wool (14). However, the data i n Table TABLE X I I I .

P h o t o s e n s i t i z e d G r a f t i n g o f Styrene to Wool F a b r i c Graft

(%)

None

20 40 60 80 90 100

2 29 55 53 73 5

(%) with S e n s i t i z e r (1%

Uranyl Nitrate 23 22 168 140 111

Benzophenone 2 2 4 22 31

w/v)

Benzoin E t h y l Ether 54 114 169 407

a

Biacetyl 22 25 23 30 52

Methanol s o l v e n t used at liquor:wool r a t i o o f 50:1; samples i r r a d i a t e d with P h i l i p s 90W high-pressure UV lamp f o r 24 hours at 24 cm from source. XIII show t h a t the e f f i c i e n c y o f the UV copolymerization i s s i g n i f i c a n t l y i n c r e a s e d i n the presence o f s e n s i t i z e r and such a process i s to be p r e f e r r e d f o r f a c i l e copolymer p r e p a r a t i o n . Of the organic s e n s i t i z e r s , benzoin e t h y l ether (BEE) was the most e f f e c t i v e i n Table X I I I , reaching a maximum i n g r a f t i n g at 90% monomer c o n c e n t r a t i o n . B i a c e t y l (BAC) i s the next most e f f e c t i v e organic s e n s i t i z e r , with benzophenone the l e a s t e f f i c i e n t , i n the same Table. Mechanism o f P h o t o s e n s i t i z e d G r a f t i n g . I t has been shown that wool k e r a t i n molecules can absorb u l t r a v i o l e t l i g h t , l e a d i n g to e x c i t e d molecules and/or r a d i c a l s which are capable o f i n i t i a t i n g copolymerization r e a c t i o n s with monomers (14,33). The f o l l o w i n g r e a c t i o n schemes have been proposed to e x p l a i n s i t e s i n wool generated by UV (Equations 2 through 5):

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND

214

-CH2-S-S-CH2

hv

-CH2-S-S-CH2

hv

PAPER CHEMISTRY AND

-CH -S

+

TECHNOLOGY

S-CH -

(2)

-CH2-S-S* + *CH -

(3)

-CO*

(4)

2

2

2

hv

-CO-NH-CH-

+ *NH-CH-

I

I

R

R n

-CO-NH-CH-

v

-CONH

+

R

CH-

(5)

R

A d d i t i o n a l g r a f t i n g s i t e s due to "secondary r e a c t i o n s " o f wool with UV have a l s o been proposed (14). With the a d d i t i o n o f s e n s i t i z e r , new g r a f t i n formed i n the wool trun energy t r a n s f e r processes or by hydrogen atom a b s t r a c t i o n r e a c t i o n s s i m i l a r to those proposed i n analogous UV g r a f t i n g to c e l l u l o s e (15). The s p e c i f i c mechanisms by which i n o r g a n i c s e n s i t i z e r s such as u r a n y l n i t r a t e and organic s e n s i t i z e r s l i k e BEE and BAC promote copolymerization have again been discussed i n d e t a i l f o r c e l l u l o s e (15) and analogous r e a c t i o n paths e x i s t i n the s e n s i t i z e d UV g r a f t i n g to wool. However, UV s e n s i t i z e d g r a f t i n g to wool i s probably more e f f i c i e n t than with c e l l u l o s e , s i n c e the s e l f - s e n s i t i z a t i o n r e a c t i o n with wool appears to be g r e a t e r than with c e l l u l o s e . A c i d Enhanced P h o t o s e n s i t i z e d G r a f t i n g . Because o f the unique p o s i t i o n o f wool, i n that simple a c i d c a t a l y s i s promotes copolymerization o f monomers to t h i s trunk polymer, the p o t e n t i a l e f f e c t o f p o s s i b l e UV enhancement o f t h i s a c i d - c a t a l y z e d process was i n v e s t i g a t e d . The data i n Table XIV show that l a r g e i n c r e a s e s i n s e n s i t i z e d g r a f t are achieved when mineral a c i d i s TABLE XIV.

Acid-Catalyzed Photosensitized Grafting to Wool F a b r i c

o f Styrene

a

Graft

Styrene (%)

20 40 60 80

None

8 170 246 285

(2) (29) (55) (53)

Uranyl Nitrate 160 1506 2487

(23) (-) (168) (40)

(%)

with S e n s i t i z e r

Benzophenone

32 98 70 138

(2) (2) (4) (22)

(1%

Benzoin Ether Ether 80 364 957 1463

(-) (54) (114) (169)

w/v) Biacetyl

103 876 2418 3087

(22) (25) (23) (30)

Methanol solvent c o n t a i n i n g 0.1N H2SO4 used at liquor:wool r a t i o o f 50:1; samples i r r a d i a t e d with P h i l i p s 90W h i g h pressure UV lamp f o r 24 hours at 24 cm from source. Figures i n brackets are g r a f t without a c i d .

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added to a l l s e n s i t i z e d systems. With BAC, u r a n y l n i t r a t e and BEE ( i n that o r d e r ) , the a c i d enhancement of the s e n s i t i z e d g r a f t i s p a r t i c u l a r l y l a r g e , i n the case of BAC the i n c r e a s e was over one hundred-fold. Mechanism o f A c i d Enhanced P h o t o s e n s i t i z e d G r a f t i n g . The f a c t that the simple a c i d - c a t a l y z e d g r a f t i n g process to wool ( i . e . without a d d i t i o n of s e n s i t i z e r ) i s enhanced by UV shows that i n many respects the UV/wool system i s analogous to g r a f t i n g with ionizing radiation. Since a c i d alone catalyzes g r a f t i n g to wool, the r o l e of UV i n enhancing t h i s a c i d g r a f t i n g without s e n s i t i z e r a d d i t i o n could be simply a r a d i a t i o n e f f e c t , i n v o l v i n g the photochemical generation o f r a d i c a l s i t e s where a c i d copolymerization may occur. Alternatively p r i m a r i l y a UV system enhance a d d i t i o n of a c i d generates more g r a f t i n g s i t e s i n the trunk polymer by mechanochemical means (discussed e a r l i e r ) ; these s i t e s then lead to increased g r a f t i n g . Both mechanisms o b v i o u s l y c o n t r i b u t e to the o v e r a l l process and i t i s d i f f i c u l t at t h i s time to u n e q u i v o c a l l y separate the c o n t r i b u t i o n o f each process to the overall grafting yield. Once r a d i c a l formation has occurred i n the trunk polymer, and monomer has d i f f u s e d to the s i t e , copolymerization i n t h i s UV system can proceed v i a a c h a r g e - t r a n s f e r mechanism s i m i l a r to that already proposed f o r g r a f t i n g i n i o n i z i n g r a d i a t i o n systems (23, 34). Such a proposal would be c o n s i s t e n t with a c i d c a t a l y s i s already observed i n general photochemical r e a c t i o n s (35), e s p e c i a l l y photo-addition processes i n v o l v i n g donor-acceptor p a i r s which are intermediates i n general charge-transfer theory. G r a f t i n g r e a c t i o n s thus c o n s t i t u t e another f i e l d i n photochemistry where a c i d c a t a l y s i s has been observed. With the a d d i t i o n o f s e n s i t i z e r to the acid-enhanced UV g r a f t i n g system, the mechanism of the o v e r a l l r e a c t i o n becomes even more complicated. The two complementary processes discussed above f o r the u n s e n s i t i z e d UV acid-enhanced g r a f t i n g are o p e r a t i v e . In a d d i t i o n , s e n s i t i z e r can generate f u r t h e r g r a f t i n g s i t e s i n the trunk polymer by hydrogen a b s t r a c t i o n r e a c t i o n s and a l s o energy t r a n s f e r processes. A c i d enhancement i n UV s e n s i t i z e d g r a f t i n g may thus be m e c h a n i s t i c a l l y c l o s e r to a c i d c a t a l y s i s i n organic photochemical r e a c t i o n s , e s p e c i a l l y those processes i n v o l v i n g proton t r a n s f e r (35) s i n c e i n s e n s i t i z e d g r a f t i n g , a donor-acceptor i n t e r a c t i o n between s e n s i t i z e r and trunk polymer p r i o r to H a b s t r a c t i o n i s involved as an intermediate i n g r a f t i n g s i t e formation. P h o t o - s e n s i t i z e d G r a f t i n g from Aqueous S o l u t i o n . For a number of reasons, e s p e c i a l l y p r e p a r a t i v e and p r a c t i c a l considera t i o n s , the u l t i m a t e technique f o r g r a f t i n g would be a pad-batch, r a p i d cure UV system, a p p l i e d from solvent or (preferably) aqueous media. In Table XV, aqueous s o l u t i o n s o f the l i s t e d monomers were padded on i n the presence o f s e n s i t i z e r and exposed f o r two

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three-minute c y c l e s t o a s i x - i n c h Hanovia lamp (200 W/inch). Soxhlet e x t r a c t i o n o f the copolymer revealed that with a c r y l i c a c i d , diethylaminoethyl methacrylate and hydroxyethyl a c r y l a t e , v i r t u a l l y 100% conversions were achieved, w h i l s t with methacrylic a c i d and hydroxyethyl methacrylate conversions o f up t o 75% were observed. One s i g n i f i c a n t feature o f the r e s u l t s i s that from c a l i b r a t i o n experiments (36), i f the present runs were c a r r i e d out on a commercial 200 W/inch lamp s p e c i a l l y focussed f o r t h i s work, cure times o f a f r a c t i o n o f a second would be expected. TABLE XV.

Photosensitized G r a f t i n g o f Some Water-Soluble Monomers to Wool F a b r i c a

Monomer S o l u t i o n Before E x t r a c t i o n 30% a c r y l i c a c i d 20% d i ethy1aminoethy1 methacrylate 30% hydroxyethyl acrylate 50% methacrylic a c i d 40% hydroxyethyl methacrylate

After Extraction

34

34

22

20

41 60

40 46

45

27

Aqueous s o l u t i o n s o f monomer c o n t a i n i n g BEE (1% f o r f i r s t 2 runs, 2% f o r remainder) padded on t o 1:1 liquor:wool r a t i o and exposed f o r 2 x 3 min t o 6 inch (200 W/inch) Hanovia high pressure UV lamp. Soxhlet e x t r a c t i o n with water f o r 8 hours. A p p l i c a t i o n o f Grafted Wools I o n i z i n g and UV i r r a d i a t i o n o f f e r p o s s i b l e a l t e r n a t i v e s t o the use o f chemicals and/or heat f o r polymerization o f monomers or c u r i n g o f prepolymers on wool, with the p o t e n t i a l bonus o f reduced energy costs and fewer e f f l u e n t problems. The d i v e r s i t y o f monomer types, plus p o s s i b i l i t i e s f o r use o f comonomer techniques and s p e c i f i c a p p l i c a t i o n o f monomer or polymer e i t h e r i n t e r n a l l y or e x t e r n a l l y t o the f i b r e , should allow m o d i f i c a t i o n o f many o f the end-use p r o p e r t i e s o f wool. Thus Needles et al. (3) and Watt (4) l i s t the f o l l o w i n g p r o p e r t i e s as being amenable t o m o d i f i c a t i o n by i n t e r n a l d e p o s i t i o n ( g r a f t i n g ) o f polymers abrasion r e s i s t a n c e , thermal s t a b i l i t y , t e n s i l e p r o p e r t i e s , t o r s i o n a l modulus, e l a s t i c i t y , s t i f f n e s s , d e n s i t y , s w e l l i n g p r o p e r t i e s , moisture regain and water s o r p t i o n c h a r a c t e r i s t i c s , p i l l i n g r e s i s t a n c e , shrinkage r e s i s t a n c e , o i l - , water- and s o i l r e p e l lancy, chemical s e t t a b i l i t y , dyeing p r o p e r t i e s , r e s i s t a n c e to l i g h t and m i c r o b i a l attack, and wear p r o p e r t i e s i n garment and carpet form.

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Thus, Batty and Guthrie (11) are using r a d i a t i o n - i n d u c e d g r a f t copolymerization o f a c r y l o n i t r i l e and v i n y l - c o n t a i n i n g r e a c t i v e d y e s t u f f s to i n c r e a s e c o l o u r f a s t n e s s on wool; simple i r r a d i a t i o n o f wool c o n t a i n i n g r e a c t i v e dyes (37) should increase the r e a c t i v i t y . Radiation g r a f t i n g has been s t u d i e d (6,10) as a means f o r s t a b i l i z i n g the improved wrinkle recovery o f wool f a b r i c s conferred by annealing (38). Stannett et al. have found that w o o l / p o l y e t h y l a c r y l a t e copolymers have increased e l a s t i c i t y and show increases i n r a t e o f d r y i n g (39,40). The presence o f p o l y e t h y l a c r y l a t e i s a l s o reported t o i n c r e a s e abrasion r e s i s tance (41,42). Internal deposition o f 4-vinyl pyridine using r a d i a t i o n procedures (6) has been shown t o improve the shrink r e s i s t a n c e o f wool f a b r i c s and at th metal-binding c a p a c i t y (6,17) copolymer formation t o i n c r e a s e the bulk o f carpet yarns (43) and improve the s e t t a b i l i t y o f wool f i b r e s (41). These authors suggest that the l a t t e r process may have a p p l i c a t i o n s i n wig making. A combined r a d i a t i o n / c h e m i c a l c u r i n g using N-methylolacrylamide has been shown t o be a v i a b l e means f o r i n c r e a s i n g c r e a s e - r e t e n t i o n and improving both the wet and dry-wrinkle recovery o f cotton f a b r i c s (44). Surface a p p l i c a t i o n o f polymer f i n i s h e s can r e s u l t i n p r a c t i c a l improvements i n shrink r e s i s t a n c e , permanent-press p r o p e r t i e s , wrinkle recovery and pigment dyeing o f wool (45), and i n t h i s area r a d i a t i o n has p o t e n t i a l f o r c u r i n g and adhesionpromotion o f prepolymers t o the f i b r e s u r f a c e , o r i n formation o f surface g r a f t s o f monomer from the vapour s t a t e o r from nons w e l l i n g s o l v e n t s . Needles et al. (12,45) have g r a f t e d a range o f a c r y l i c monomers onto wool using photo-initiâtion, while water-, o i l - and s o i l - r e p e l l a n c y has been conferred on cotton t e x t i l e s by UV-grafting o f f l u o r o a l k y l a c r y l a t e s from the vapour s t a t e (46). Current i n t e r e s t i n v o l v e s UV-curing as a replacement f o r heat-curing o f p a i n t s , coatings and i n k s , u s i n g a U V - s e n s i t i z e r and p o l y f u n c t i o n a l a c r y l a t e monomer, a p p l i e d with conventional prepolymer types such as p o l y e s t e r s , a c r y l i c s , a l k y l s and p o l y urethanes (47-49). This type o f system has been shown t o be a p p l i c a b l e t o wool f a b r i c (36), as have s i l i c o n e polymer systems c o n t a i n i n g v i n y l s i l i c o n e s (36,50). UV and i o n i z i n g r a d i a t i o n have a l s o been used to g r a f t phosphorus c o n t a i n i n g monomers t o impart flame p r o o f i n g t o wool (6,17), the process p a r t i c u l a r l y with UV, appearing t o be amenable t o r a p i d cure procedures. F i n a l l y , there i s the p o s s i b i l i t y that copolymers o f wool prepared by both UV and i o n i z i n g r a d i a t i o n could be u t i l i z e d advantageously f o r the immobilization o f enzymes (51) and the h e t e r o g e n i z a t i o n o f homogeneous metal complexes (52), two f i e l d s which at present have been predominantly confined t o the p o l y o l e f i n s (51,52) and polyv i n y l c h l o r i d e (53). The r e s u l t s o f present work (36,54) suggest that wool could be o f value i n t h i s a p p l i c a t i o n , p a r t i c u l a r l y i n processes approaching UV r a p i d cure. These are the types o f

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systems that are currently being explored for wool uses in the grafting field. Acknowledgements. We thank the Australian Institute of Nuc­ lear Science and Engineering, the Australian Atomic Energy Commission and the Australian Wool Corporation for continued support. We are also grateful to the following co-workers who at some time were responsible for part of this work: Drs. Davids, Davis, Dilli, Fletcher, Kenyon and Phuoc. Literature Cited 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22.

Dilli, S., Garnett, J.L., Kenyon, R.S., Martin, E.C., Phuoc, D.H., Yen, Y. Leeder J.D. J Macromol Sci Chem (1972), A6, 719. Delmenico, J., Fleischfresser, , y (1972), 10, 78. Needles, H.L., Sarsfield, L.J., Dowhaniuk, D.M., Textile Res.J. (1972), 42, 558. Watt, I.C., J. Macromol. Sci. (1970), C5, 175. Gupta, K., Wool and Woollens of India (1968), 5, 43. Garnett, J.L., Guise, B., Leeder, J.D., in preparation. Burke, Μ., Kenny, P., Nicholls, C H . , J. Textile Inst. (1962), 53, T370. Armstrong, A.A. Jr., Rutherford, H.A., Textile Res. J. (1963), 33, 264. Stannett, V.T., Araki, K., Gervasi, J.Α., McLeskey, S.W., J. Polymer Sci. (1961), 3, 3763. D'Arcy, R.L., Watt, I.C., McLaren, K.G., J. Macromol. Sci. Chem. (1972), A6, 689. Batty, N.S., Guthrie, J.T., Abstracts, 5th Int. Wool Text. Res. Conf. Aachen (1975), p.341. Needles, H.L., Alger, K.W., Abstracts, 5th Int. Wool Text. Res. Conf. Aachen (1975), p.316. Needles, H.L., J. Appl. Polymer Sci., (1971), 15, 2559; (1972), 16, 337. Ishibashi, Η., Oku, Μ., 3rd Int. Wool Text. Res. Conf. Paris (1965), Vol. 3, p.385. Garnett, J.L., This Conference, in press. Kenyon, R.S., Garnett, J.L., Polymer Letters (1973), 11, 651. Garnett, J.L., Kenyon, R.S., in press. Williams, J . L . , Stannett, V.T., Polymer Letters (1970), 8, 711. Lipson, M., Speakman, J.B., J. Soc. Dyers and Colourists (1949), 65, 390. Odian, G., Rossi, Α., Ratchek, E . , Acker, T., J. Polymer Sci. (1961), 54, 511. Dilli, S., Garnett, J.L., J. Appl. Polymer Sci. (1967), 11, 839. Garnett, J.L., Yen, N.T., Polymer Letters (1974), 2, 2259.

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Barker, Η., Garnett, J.L., Kenyon, R.S., Levot, R., Liddy, M.S., Long, M.A., Proc. VIth Inter. Cong. Catalysis, London (1976), in press. Barker, Η., Garnett, J . L . , Levot, R., Proc. 2nd Inter. Symp. Polyvinylchloride, Lyon-Villeurbanne (1976), in press. Garnett, J . L . , Levot, R., in preparation.

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In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

13 Technical Needs and Developments in the Paper Industry of the United States JOHN C. WOLLWAGE and ROY P. WHITNEY The Institute of Paper Chemistry, Appleton, WI

In recent years, staf Chemistry have engaged periodicall future needs of the pulp and paper industry of the United States, in order that our research programs might be better planned and implemented. This exercise has undoubtedly gone forward at essentially every research institution, both i n this country and throughout the world, and there has been ample evidence of this in the various papers presented at this meeting. There is no reason to suppose that our approach has been essentially different from those used elsewhere, and certainly many of our conclusions are in good agreement with those which have already been presented. Our general approach has been to try to identify some of the important external forces and trends which are evident in this country and which must have their effect on the pulp and paper industry. Next, we have tried to assess the impact of these externalities on the industry and particularly on its future development. From these considerations, we have then tried to develop priority areas for research and development to meet the future needs of the industry, as i t continues its process of evolution. Figure 1 l i s t s some of the external forces which we believe w i l l have an important impact upon the future pulp and paper i n dustry of the United States. It seems inevitable that the first entry must be political forces, since they exert such an influence not only on industry but on the daily lives of a l l of us. Industry must look forward to increased governmental involvement in its affairs, and to greater government regulation. Social forces can hardly be divorced from those p o l i t i c a l . Generally, we believe that industry can anticipate higher labor costs, and a decreased rate of rise in the standard of living of the general population of this country. We can also anticipate increasingly stringent requirements with respect to both air and water environmental considerations, and increased pressure for the conservation of natural resources and the reuse of waste materials. 223

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W i t h r e s p e c t t o p o p u l a t i o n t r e n d s , t h e e x p e r t s t e l l us t h a t the t o t a l population of the United States w i l l continue to i n c r e a s e , b u t a t a d e c r e a s i n g r a t e , and t h a t t h e b i r t h r a t e w i l l continue i t s present d e c l i n e . I n f l a t i o n w i l l c o n t i n u e t o be w i t h u s , a l t h o u g h h o p e f u l l y a t a more m o d e s t r a t e t h a n t h a t e x p e r i e n c e d d u r i n g t h e p a s t y e a r o r two. The p r e s e n t d e c r e a s e i n i n f l a t i o n a r y t r e n d s i s c e r t a i n ly encouraging. The a v a i l a b i l i t y o f c a p i t a l f o r e x p a n s i o n and g r o w t h i s a f o r c e of r e a l concern. Many k n o w l e d g e a b l e p e o p l e h a v e s p o k e n on t h i s p o i n t r e c e n t l y , and h a v e p r o j e c t e d v a r i o u s s h o r t f a l l s o f capital availability. I t appears p o s s i b l e t h a t c a p i t a l c o n s i d e r a t i o n s may r e s t r i c t f u t u r e i n d u s t r i a l g r o w t h i n t h i s c o u n t r y , u n l e s s governmental r e g u l a t i o n investment. The p i c t u r e w i t h r e s p e c t t o t h e a v a i l a b i l i t y o f raw m a t e r i a l s i s c o n s i d e r a b l y b r i g h t e r . F o r t u n a t e l y , c e l l u l o s e i s a renewa b l e raw m a t e r i a l i n q u a n t i t i e s w h i c h , t o some c o n s i d e r a b l e e x t e n t , may be c o n t r o l l e d . S o c i a l f o r c e s h o w e v e r , s e e k t o r e s t r i c t i t s h a r v e s t i n g and u s e . The a v a i l a b i l i t y o f e n e r g y i s a much d i s c u s s e d and h i g h l y c o n t r o v e r s i a l s u b j e c t . I n o u r d e l i b e r a t i o n s , we h a v e assumed t h a t a d e q u a t e e n e r g y w i l l be a v a i l a b l e i n t h e f u t u r e , a l t h o u g h c o s t w i l l o b v i o u s l y be an i m p o r t a n t c o n s i d e r a t i o n . We h a v e f u r t h e r assumed t h a t t h e m a j o r i n c r e a s e s i n e n e r g y c o s t s h a v e a l r e a d y b e e n e x p e r i e n c e d , and t h a t f u r t h e r c o s t i n c r e a s e s w i l l be more m o d e s t . T h e s e , t h e n , a r e some o f t h e m a j o r e x t e r n a l f o r c e s w h i c h we h a v e i d e n t i f i e d as e x e r t i n g a n i m p o r t a n t i n f l u e n c e upon t h e d e v e l o p m e n t o f t h e p u l p and p a p e r i n d u s t r y . As n o t e d e a r l i e r , , t h e n e x t s t e p i n o u r p l a n n i n g p r o c e s s has b e e n t o t r y t o a s s e s s t h e i m p a c t o f t h e s e e x t e r n a l f o r c e s on t h e f u t u r e d e v e l o p m e n t o f t h e U n i t e d S t a t e s p u l p and p a p e r industry. F i g u r e 2 shows some o f t h e c a t e g o r i e s w h i c h h a v e b e e n considered. T h e r e i s no d o u b t t h a t c a p i t a l c o s t s w i l l be a m a j o r f a c t o r i n t h e f u t u r e d e v e l o p m e n t o f t h i s i n d u s t r y . The p u l p and p a p e r i n d u s t r y i s h i g h l y c a p i t a l i n t e n s i v e , a n d t h e c a p i t a l c o s t o f new f a c i l i t i e s has b e e n i n c r e a s i n g a t a s t a g g e r i n g r a t e d u r i n g t h e p a s t few y e a r s . A l t h o u g h c o s t s v a r y c o n s i d e r a b l y , depending upon t h e t y p e o f f a c i l i t y , t h e c a p i t a l c o s t o f c o n s t r u c t i n g a new i n t e g r a t e d k r a f t p u l p and p a p e r m i l l i s now i n t h e v i c i n i t y o f $350,000/daily t o n o f p r o d u c t i o n . I t seems e v i d e n t t h a t i n any r e s e a r c h a i m e d a t new p r o c e s s e s and new f a c i l i t i e s , c a p i t a l c o s t s must be a m a j o r c o n s i d e r a t i o n , and c o m p l e x and i n t r i c a t e p r o c e s s e s , h o w e v e r d e s i r a b l e o t h e r w i s e , may w e l l be r u l e d o u t on t h e basis of cost. 9

O p e r a t i n g c o s t s must a l s o be a p r i m e c o n s i d e r a t i o n i n r e s e a r c h a i m e d a t new p r o c e s s e s a n d p r o d u c t s . In a d d i t i o n to the f i x e d charges a s s o c i a t e d w i t h c a p i t a l , the i n c r e a s i n g cost of

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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raw m a t e r i a l s , l a b o r , and e n e r g y w i l l p l a y an i m p o r t a n t r o l e i n d e c i s i o n m a k i n g . C l e a r l y , t h e r e s e a r c h e r must become much more c o s t c o n s c i o u s t h a n he has b e e n i n t h e p a s t . I t seems e v i d e n t t h a t t h e i m p a c t o f t h e s e e x t e r n a l f o r c e s make i t i n e v i t a b l e t h a t i n c r e a s e d e m p h a s i s must be p l a c e d on new p r o c e s s d e v e l o p m e n t . I t i s now t r i t e t o s a y t h a t t h e p u l p and p a p e r i n d u s t r y i s s a d d l e d w i t h an o l d and t i r e d t e c h n o l o g y , b u t i t i s n e v e r t h e l e s s s t i l l t r u e . Our p r o c e s s e s w e r e d e v e l o p e d a t a t i m e when e x t e r n a l i t i e s w e r e a m i n o r c o n s i d e r a t i o n . They a r e n o t g o o d enough f o r t h e f u t u r e . P r o c e s s c o n t r o l , and p a r t i c u l a r l y p r o c e s s a u t o m a t i o n , must p l a y an i n c r e a s i n g l y i m p o r t a n t r o l e i n o u r r e s e a r c h o f t o d a y and o u r p r o c e s s e s o f t o m o r r o w . D e c r e a s e s i n o p e r a t i n g c o s t s , and i m p r o v e m e n t s i n p r o d u c t q u a l i t y , a r e o n l y two o f t h e r e a s o n s why t h i s i s s o . Environmental c o n t r o o f t h e p u l p and p a p e r i n d u s t r y , and c e r t a i n l y i t s i m p a c t w i l l n o t diminish. I t has b e e n e s t i m a t e d t h a t a b o u t 30% o f t h e p r e s e n t c a p i t a l i n v e s t m e n t o f t h e i n d u s t r y i s consumed i n e n v i r o n m e n t a l c o n t r o l f a c i l i t i e s (JL). T h i s must be an i n t e g r a l p a r t o f o u r t h i n k i n g and o f o u r r e s e a r c h . We a c c e p t as a x i o m a t i c t h e v i e w p o i n t t h a t no r e s e a r c h on new p r o c e s s e s o r new f a c i l i t i e s i s v i a b l e u n l e s s adequate s o l u t i o n s are found t o a l l of the e n v i r o n m e n t a l p r o b l e m s w h i c h may r e s u l t . E n e r g y c o n s e r v a t i o n m u s t a l s o be an i n t e g r a l c o n s i d e r a t i o n i n a l l of our r e s e a r c h a c t i v i t i e s . The p u l p and p a p e r i n d u s t r y i s fortunate i n that i t generates a considerable f r a c t i o n of i t s t o t a l energy r e q u i r e m e n t s . M o n t h l y f i g u r e s c o m p i l e d by t h e A m e r i c a n P a p e r I n s t i t u t e (2) show t h a t t h e i n d u s t r y g e n e r a t e d a l m o s t kk% o f i t s t o t a l 1975 energy consumption from b a r k , hogged f u e l , s p e n t p u l p i n g l i q u o r s , and h y d r o e l e c t r i c p o w e r . T h i s i s an i n c r e a s e f r o m k2% i n 1972, and p r o j e c t i o n s a r e t h a t t h e i n d u s t r y can g e n e r a t e a c o n s i d e r a b l y h i g h e r f r a c t i o n o f i t s e n e r g y r e q u i r e m e n t s , p a r t i c u l a r l y t h r o u g h t h e u s e o f a d d i t i o n a l wood w a s t e . N e v e r t h e l e s s , i n a l l o f o u r r e s e a r c h , we must s t r i v e t o k e e p e n e r g y r e q u i r e m e n t s a t a minimum. The l a s t i t e m i n F i g u r e 2 i s p r o d u c t s h i f t s . The p u l p and p a p e r i n d u s t r y has h a d a c o n t i n u e d h i s t o r y o f s h i f t s i n i t s p r o d u c t m i x , a c c o r d i n g t o m a r k e t demands. D u r i n g t h e p a s t c e n t u r y , i t has gone f r o m an i n d u s t r y h e a v i l y c o m m i t t e d t o w r i t i n g and p r i n t i n g p a p e r s t o one i n w h i c h n e a r l y h a l f o f i t s o u t p u t g o e s i n t o p a c k a g i n g and p a p e r b o a r d c o n t a i n e r s . I t has c o n t i n u a l l y l o s t m a r k e t s t o o t h e r m a t e r i a l s b u t i t has a l w a y s g a i n e d more new m a r k e t s t h a n i t has l o s t o l d o n e s . I t i s i n e v i t a b l e t h a t i t w i l l c o n t i n u e t o l o s e o l d m a r k e t s i n t h e f u t u r e , and t h e r e f o r e t h a t i t must c o n t i n u e t o g a i n new o u t l e t s f o r i t s p r o d u c t s . No c h a l l e n g e i s more v i t a l t o t h e r e s e a r c h e r t h a n t h e d e v e l o p m e n t o f new products. Having attempted t o assess the impact of c e r t a i n e x t e r n a l f o r c e s on t h e p u l p and p a p e r i n d u s t r y o f t h e f u t u r e , we t u r n now

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t o p r i o r i t y a r e a s f o r r e s e a r c h a n d d e v e l o p m e n t . The p r o b l e m s "which n e e d t o b e s o l v e d a r e many, a n d i t i s d i f f i c u l t t o d e t e r m i n e t h e r e l a t i v e i m p o r t a n c e o f e a c h . We s h a l l c h o o s e a f e w f o r comments, f o l l o w i n g t h e o u t l i n e o f F i g u r e 3 * w i t h t h e s t i p u l a t i o n t h a t t h e e a r l i e r d i s c u s s i o n regarding t h e impact o f e x t e r n a l f o r c e s must b e a p p l i e d i n e a c h i n s t a n c e . Wood i s t h e m a j o r r a w m a t e r i a l o f t h e p u l p a n d p a p e r i n d u s try. I n t h e y e a r s t o come, t h e i n d u s t r y must p r o c u r e a n e v e r i n c r e a s i n g q u a n t i t y o f wood f r o m a n e v e r - d e c r e a s i n g l a n d b a s e . T h u s , t h e m a j o r n e e d i s t o r e a l i z e h i g h e r y i e l d s o f wood f i b e r p e r a c r e o f l a n d . The f o r e s t b i o l o g i s t s a n d f o r e s t e r s h a v e a l r e a d y made c o n s i d e r a b l e p r o g r e s s i n a c h i e v i n g t h i s g o a l . The d e v e l o p m e n t a n d u s e o f g e n e t i c a l l y - i m p r o v e d t r e e s shows great promise. Severa show t w i c e t h e g r o w t h r a t n a t i v e s p e c i e s o f P o p u l u s (3.). G e n e t i c s t u d i e s on o t h e r s p e c i e s are c o n t i n u i n g . I n c r e a s e s i n volume growth o f 2 0 t o 3 0 $ appear p o s s i b l e u s i n g s e l e c t i o n and seed orchard approaches. Improved f o r e s t management i s p a y i n g d i v i d e n d s . Great i n t e r e s t i s prese n t l y b e i n g shown i n more c o m p l e t e u t i l i z a t i o n o f t h e t r e e s w h i c h are harvested. Whole t r e e c h i p p i n g i s u n d e r i n t e n s e s t u d y , a n d e v e n t h o u g h s e r i o u s p r o b l e m s r e m a i n , f u r t h e r g a i n s w i l l b e made. The u s e o f wood r e s i d u e s , a s f r o m p l y w o o d a n d s a w m i l l o p e r a t i o n s , has been i n c r e a s i n g s t e a d i l y and w i l l continue t o do s o . Wood r e s i d u e s now c o n s t i t u t e t h e m a j o r s u p p l y o f wood t o p u l p m i l l s i n t h e w e s t e r n U n i t e d S t a t e s a n d a r e b e c o m i n g more s i g n i f i c a n t i n other parts o f the country. Research leading t o more c o m p l e t e u t i l i z a t i o n o f t h e h a r v e s t e d t r e e i s c e r t a i n l y a p r i o r i t y area f o r the f u t u r e . A f t e r t r e e s , t h e n e x t most i m p o r t a n t s o u r c e o f f i b r o u s r a w m a t e r i a l s comes f r o m w a s t e p a p e r o r s e c o n d a r y f i b e r . Currently, s e c o n d a r y f i b e r makes u p a b o u t 22% o f t h e t o t a l f i b r o u s m a t e r i a l s used by t h e i n d u s t r y . I t slong-term u t i l i z a t i o n r a t e i s i n c r e a s ing, i n s p i t e o f the aberration o f the past year o r so. I t i s p r e d i c t e d t h a t s e c o n d a r y f i b e r w i l l make u p a b o u t 30% o f t h e r a w m a t e r i a l base w i t h i n t h e n e x t decade. Problems i n t h e use o f i n c r e a s e d q u a n t i t i e s o f waste paper are both l o g i s t i c a l and t e c h n i c a l . C o l l e c t i o n and s o r t i n g a r e d i f f i c u l t , and t o a c o n s i d e r a b l e e x t e n t w i l l p r o b a b l y r e s t r i c t the major use o f secondary f i b e r t o l a r g e m e t r o p o l i t a n areas. The t e c h n i c a l p r o b l e m s a r e v a r i e d , b u t h a v e t o d o p a r t i c u l a r l y w i t h t h e e l i m i n a t i o n o f c o n t a m i n a n t s w h i c h f i n d t h e i r way i n t o t h e w a s t e p a p e r s t r e a m s . A l t h o u g h t h e c o n t a m i n a n t s a r e many a n d v a r i e d , t h e ones p r o b a b l y c a u s i n g t h e g r e a t e s t p r e s e n t c o n c e r n are p o l y c h l o r i n a t e d biphenyls. T u r n i n g now t o p r o c e s s e s , t h e p u l p i n g o f wood i s a m a j o r p r i o r i t y area f o r research. Today*s c o m m e r c i a l l y - i m p o r t a n t pulpi n g p r o c e s s e s w e r e c o n c e i v e d i n t h e 19th c e n t u r y , a l t h o u g h t h e y have been r e f i n e d and d e v e l o p e d c o n s i d e r a b l y i n r e c e n t decades.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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Materials Roundwood Wood R e s i d u e s

Processes Pulping Bleaching Papermaking Converting Products Quality Specification Performance Figure 3. Priority areas for research and development

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I t i s probable t h a t the o p p o r t u n i t i e s f o r f u r t h e r refinement and improvement a r e l i m i t e d . T h e groundwood p u l p i n g p r o c e s s r e m a i n s v i a b l e , s i n c e i t produces a r e l a t i v e l y inexpensive pulp i d e a l l y s u i t e d f o r newsprint and other low-grade p r i n t i n g papers. Signif i c a n t i m p r o v e m e n t s a r e now b e i n g made i n m e c h a n i c a l p u l p s , howe v e r , p r o b a b l y t h e most i m p o r t a n t b e i n g i n t h e development o f t h e t h e r m o m e c h a n i c a l p r o c e s s . H e r e , wood c h i p s a r e m e c h a n i c a l l y r e duced t o p u l p i n a r e f i n e r , operated a t e l e v a t e d temperature and pressure* By v a r y i n g p r o c e s s c o n d i t i o n s , t h e major zones o f f r a c t u r e c a n b e made t o o c c u r i n t h e c e l l u l o s e f i b e r s , t h u s p r o ducing a pulp w i t h r e l a t i v e l y l a r g e c e l l u l o s e areas exposed, o r c a n b e s h i f t e d t o t h e m i d d l e l a m e l l a a r e a made u p l a r g e l y o f lignin. S u c h f i b e r b u n d l e s , w i t h much o f t h e l i g n i n e x p o s e d , show p r o m i s e o f p r o v i d i n superio material fo furthe chemi cal treatment. Althoug new m e c h a n i c a l a n d c h e m i m e c h a n i c a pulp y i m p r o v e m e n t s o v e r t h e t r a d i t i o n a l groundwood p u l p s , and w i l l i n e v i t a b l y p l a y an important r o l e i n the f u t u r e . I n t h e c h e m i c a l p u l p i n g a r e a , t h e k r a f t p r o c e s s p l a y s an i n c r e a s i n g l y dominant r o l e . T h e number o f e x i s t i n g k r a f t m i l l s , and t h e c a p i t a l i n v e s t m e n t w h i c h t h e y r e p r e s e n t , i n s u r e t h a t t h i s w i l l continue f o r a t l e a s t the next s e v e r a l decades. I n s p i t e o f t h i s , t h e k r a f t p r o c e s s shows s e r i o u s s h o r t c o m i n g s , p e r h a p s c h i e f among t h e m b e i n g a r e l a t i v e l y l o w y i e l d , s a f e t y c o n s i d e r a t i o n s , and a h i g h c a p i t a l i n t e n s i t y . R e s e a r c h i s underway i n many l a b o r a t o r i e s a i m e d a t t h e d e v e l o p m e n t o f i m p r o v e d c h e m i c a l p u l p i n g p r o c e s s e s . The g o a l s t o be a c h i e v e d a r e a s i g n i f i c a n t l y i n c r e a s e d y i e l d o f p u l p f r o m wood, freedom from e n v i r o n m e n t a l p r o b l e m s , and a marked decrease i n c a p i t a l cost per u n i t o f production. The r e s e a r c h i n c h e m i c a l p u l p i n g w h i c h a p p e a r s t o show t h e most p r o m i s e i s t h e s o - c a l l e d o x y g e n / a l k a l i p r o c e s s , i n v o l v i n g o x y g e n a s t h e m a j o r p u l p i n g r e a g e n t i n a n a l k a l i n e medium. A l t h o u g h s i g n i f i c a n t p r o g r e s s h a s b e e n made, s e r i o u s p r o b l e m s r e main. These i n c l u d e e x c e s s i v e c a r b o h y d r a t e d e g r a d a t i o n a n d an inadequate i n c r e a s e i n y i e l d . Some r e d u c t i o n i n c a p i t a l i n t e n s i t y seems t o b e p o s s i b l e , and t h e a p p r o a c h shows c o n s i d e r a b l e promise from the environmental s t a n d p o i n t . E i t h e r through the u s e o f o x y g e n / a l k a l i o r o t h e r r e a g e n t s , m a r k e d l y i m p r o v e d chemi c a l p u l p i n g p r o c e s s e s are u r g e n t l y needed f o r the f u t u r e . M o s t p u l p b l e a c h i n g p r o c e s s e s e m p l o y c h l o r i n e compounds, w i t h c h l o r i n e d i o x i d e assuming an i n c r e a s i n g l y dominant r o l e . Probably the p r i n c i p a l deficiency i n bleaching i s i n the enviro n m e n t a l a r e a , where l a r g e v o l u m e s o f b l e a c h e f f l u e n t s h a v e b e e n d i s c h a r g e d t o streams and r i v e r s . I t i s imperative that the b l e a c h e f f l u e n t p r o b l e m b e s o l v e d , a n d p r o g r e s s i s b e i n g made. The u s e o f c o m p l e t e c o u n t e r c u r r e n t w a s h i n g i n t h e v a r i o u s s t a g e s o f a b l e a c h p l a n t , p r e v i o u s l y f e l t t o b e i m p r a c t i c a l , i s now coming i n t o commercial u s e . T h e o x y g e n / a l k a l i a p p r o a c h has b e e n shown t o b e e f f e c t i v e i n b l e a c h i n g a s w e l l a s i n p u l p i n g , a n d i s

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i n c o m m e r c i a l o p e r a t i o n . I t seems t o "be p a r t i c u l a r l y w e l l a d a p t ed t o t h e f i r s t s t a g e i n b l e a c h i n g , where t h e major o b j e c t i v e i s removal o f l i g n i n . Used as a f i r s t b l e a c h i n g s t a g e , t h e e f f l u e n t i s e s s e n t i a l l y c h l o r i n e - f r e e a n d c a n be c o m b i n e d w i t h t h e s p e n t l i q u o r s from the p u l p i n g o p e r a t i o n f o r chemical recovery. A m a j o r r e s e a r c h o b j e c t i v e i n t h e b l e a c h i n g a r e a must be t o c l o s e up t h e b l e a c h i n g s y s t e m a n d t o e l i m i n a t e a n y aqueous e f f l u e n t d i s c h a r g e . One i n t e r e s t i n g a p p r o a c h t o t h i s p r o b l e m h a s b e e n p r o p o s e d , i n w h i c h t h e b l e a c h i n g e f f l u e n t i s combined w i t h t h e e f f l u e n t f r o m t h e p u l p i n g o p e r a t i o n s , and t h e n s e n t t h r o u g h t h e c o n v e n t i o n a l k r a f t r e c o v e r y system. C h l o r i d e s a r e removed f r o m the system by c r y s t a l l i z a t i o n - e v a p o r a t i o n o f t h e w h i t e l i q u o r . A c o m m e r c i a l i n s t a l l a t i o n i s now u n d e r c o n s t r u c t i o n (k). I t would appear t h a i s t o remove s u l f u r f r o b l e a c h i n g s y s t e m . "While t h i s c a n now b e a c c o m p l i s h e d i n t h e l a b o r a t o r y , u s i n g s u c h r e a g e n t s a s p e r a c e t i c a c i d , any s u c h s y s t e m i s f a r r e m o v e d f r o m an e c o n o m i c a l l y f e a s i b l e c o m m e r c i a l o p e r a t i o n . Much r e s e a r c h r e m a i n s t o b e done. I n the papermaking a r e a , major r e s e a r c h o b j e c t i v e s center around p r o d u c t q u a l i t y , e n v i r o n m e n t a l c o n t r o l , and energy r e duction. The f o u r d r i n i e r p a p e r m a c h i n e , d o m i n a n t i n t h e manuf a c t u r e o f most p a p e r g r a d e s s i n c e i t s i n v e n t i o n i n 1800, i s now b e i n g s e r i o u s l y c h a l l e n g e d b y t h e t w i n - w i r e f o r m e r s . Some i m provement i n s h e e t q u a l i t y i s p o s s i b l e , b u t so f a r t h e t w i n - w i r e f o r m e r s h a v e f a i l e d t o show t h e g r e a t v e r s a t i l i t y o f t h e f o u r d r i nier. N e v e r t h e l e s s , f u r t h e r i m p r o v e m e n t s w i l l be made, and t h e twin-wire formers w i l l undoubtedly f i n d increased a p p l i c a t i o n i n the future. Papermaking i n t h e p a s t has s u f f e r e d from t h e e n v i r o n m e n t a l p r o b l e m o f d i s c h a r g i n g huge v o l u m e s o f w h i t e w a t e r c o n t a i n i n g f i b r o u s m a t e r i a l s , f i l l e r s , and o t h e r papermaking a d d i t i v e s . A l t h o u g h p r o g r e s s has b e e n made i n c l o s i n g up w h i t e w a t e r s y s t e m s a n d i n u s i n g t h e w a t e r i n t e r n a l l y , much s t i l l r e m a i n s t o be d o n e . P r o g r e s s h a s a l s o b e e n made o n t h e t r e a t m e n t o f p a p e r m i l l e f f l u ents b e f o r e t h e y a r e d i s c h a r g e d i n t o the waterways. Aeration, s e t t l i n g , b i o l o g i c a l t r e a t m e n t s , and o t h e r approaches have p r o v e d t o be h i g h l y b e n e f i c i a l , b u t f u r t h e r w o r k i s n e c e s s a r y . F o r example, s u c h t r e a t m e n t s u s u a l l y g i v e r i s e t o s l u d g e s w h i c h dew a t e r w i t h g r e a t d i f f i c u l t y , and t h e adequate t r e a t m e n t , r e u s e , o r d i s p o s a l o f s u c h s l u d g e s r e m a i n s a p r o b l e m w h i c h m u s t be s o l v ed. D r y i n g i s one o f t h e m a j o r consumers o f e n e r g y i n t h e p a p e r m a k i n g p r o c e s s . A l t h o u g h 98-99$ o f t h e w a t e r u s e d i n m a k i n g p a p e r i s removed m e c h a n i c a l l y , t h e e n e r g y c o n s u m p t i o n i n r e m o v i n g t h e l a s t 1-2% b y e v a p o r a t i o n i s c o n s i d e r a b l e . T h e r e h a s b e e n r e l a t i v e l y l i t t l e p r o g r e s s i n p a p e r d r y i n g i n r e c e n t y e a r s , and t h e p r o b l e m o f e n e r g y r e d u c t i o n i s one w h i c h must b e s t u d i e d more i n t e n s i v e l y . P e r h a p s one o f t h e more p r o m i s i n g a p p r o a c h e s l i e s not i n t h e d r i e r s e c t i o n i t s e l f , b u t i n t h e p r e s s s e c t i o n which

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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A N D WHITNEY

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precedes i t and which governs the water content o f the sheet ent e r i n g the d r i e r s . I n a t l e a s t one r e s e a r c h i n s t i t u t i o n , a m a j o r study o f p r e s s i n g i s underway, w i t h t h e o b j e c t i v e o f r e d u c i n g t h e m o i s t u r e c o n t e n t o f t h e s h e e t w i t h o u t damaging i t s q u a l i t y . The o p e r a t i o n s o f c o n v e r t i n g a r e h i g h l y d i v e r s i f i e d , a n d l a r g e l y mechanical. They h a v e t y p i c a l l y r e p r e s e n t e d h i g h l a b o r costs, and r e l a t i v e l y low c a p i t a l c o s t s . E f f o r t s w i l l continue t o s i m p l i f y c o n v e r t i n g o p e r a t i o n s , and t o develop automation t o an e x t e n t c o m p a t i b l e w i t h t h e i n c r e a s e d c a p i t a l r e q u i r e m e n t s . To enter i n t o a d e t a i l e d d i s c u s s i o n o f the h i g h l y v a r i e d and d i v e r s i f i e d o p e r a t i o n s o f c o n v e r t i n g i s b e y o n d t h e s c o p e o f t h i s paper. P r o d u c t q u a l i t y i s a n d must r e m a i n a p r i m e c o n c e r n t o t h e pulp and paper i n d u s t r y . Research s t u d i e s o f the p h y s i c a l and chemical properties o b e e n u n d e r w a y f o r many h i g h p r i o r i t y r e s e a r c h l i e s i n t h e d e v e l o p m e n t o f means f o r t h e o n - m a c h i n e n o n d e s t r u c t i v e measurement o f p a p e r p r o p e r t i e s . W h i l e some p r o g r e s s h a s b e e n made i n t h i s r e g a r d , p a r t i c u l a r l y a s r e g a r d s m o i s t u r e c o n t e n t , much r e m a i n s t o b e done b e f o r e t h e p r o p e r t i e s r e l a t e d t o paper s t r e n g t h and other use c h a r a c t e r i s t i c s can be measured s a t i s f a c t o r i l y a n d c o n t i n u o u s l y o n t h e moving web. Research i n t h i s area i s s t i l l i n i t s e a r l y stages, and must b e g i v e n more a t t e n t i o n i n t h e f u t u r e . F i n a l l y , more m u s t b e done t o m a t c h p a p e r s p e c i f i c a t i o n s t o end u s e r e q u i r e m e n t s . F o r example, i n t h i s e r a o f g r e a t e n v i r o n m e n t a l c o n c e r n , a r e t h e u l t r a - h i g h - b r i g h t n e s s s h e e t s now demanded by many consumers r e a l l y n e c e s s a r y ? Are d i r t s p e c i f i c a t i o n s unrealistic? C a n g r e a t e r amounts o f s e c o n d a r y f i b e r , w i t h t h e a t t e n d a n t d e t e r i o r a t i o n i n sheet q u a l i t y , b e t o l e r a t e d ? Can s p e c i f i c a t i o n s be d e v e l o p e d f o r c o r r u g a t e d c o n t a i n e r s w h i c h b e a r a more r e a l i s t i c r e l a t i o n s h i p t o e n d u s e r e q u i r e m e n t s ? I t seems i n e v i t a b l e t h a t environmental concerns, energy c o s t s , c a p i t a l and l a b o r c o s t s , and o t h e r s o c i a l concerns w i l l e x e r t a marked e f f e c t on many o f t h e f u t u r e p r o d u c t s o f t h e p u l p a n d p a p e r i n d u s t r y . LITERATURE CITED 1. A m b e r g , Herman R. " F u t u r e T e c h n i c a l T r e n d s a n d Needs o f t h e Paper I n d u s t r y ; Environmental and S o c i a l F a c t o r s . " Paper p r e s e n t e d a t t h e 1976 A n n u a l M e e t i n g , T e c h n i c a l A s s o c i a t i o n o f t h e P u l p a n d P a p e r I n d u s t r y , New Y o r k , M a r c h 17» 1976. 2. S l i n n , R o n a l d J . " E n e r g y C o n s e r v a t i o n i n t h e U.S. P u l p , Paper, and Paperboard I n d u s t r y . " Paper presented a t t h e A n n u a l M e e t i n g o f t h e A P I P u l p , F i b e r a n d Raw M a t e r i a l s G r o u p , New Y o r k , M a r c h 15, 1976. 3. E i n s p a h r , D. W. P r i v a t e C o m m u n i c a t i o n , M a r c h , 1976. k. R a p s o n , W. H. "The C l o s e d C y c l e B l e a c h e d K r a f t P u l p M i l l . " Paper presented a t the N a t i o n a l Meeting o f the American I n s t i t u t e o f C h e m i c a l E n g i n e e r s , B o s t o n , S e p t . , 1975·

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

14 Interrelation between the Paper and Plastics Industries VLADIMIR M. WOLPERT Wolpert & Jones (Studies) Ltd., London, England

The growing symbiosis between the forest-based industry and the chemical industr this trend is bound to , are still many not utilized possibilities of extending the cooperation between these two industries. Next to co-operation there is also a growing competition between these two industries, as synthetic polymer products have been penetrating some markets of the pulp/paper industry, and I will try to evaluate whether this trend is to continue or whether it will be reversed. At present, the chemical industry (of which the plastics industry is an integral part) is a major supplier of many products to various sectors of the forest-based industry in the manufacture of products, the functional properties of which could not be achieved without these chemicals, including synthetic polymers. In fact, the pulp/paper industry has gradually developed from a purely mechanical to a mechanical cum chemical industry. Increasing tonnages of synthetic polymers are being used before, during, and after the actual papermaking process. The forest-based industry (of which the paper industry is an important integral part) in addition to supplying packaging materials to the chemical industry, has been supplying the chemical industry with crude tall oil, turpentine, extractive products isolated during the kraft pulp process, plus products from pine trees and stumps, amounting to about 500,000 tpa. in the United States. In addition, lignosulphonates have been finding a growing number of applications, like dispersants, oilwell drilling additives, emulsifiers, etc. Even i f the sulphite pulping process accounts for a comparatively small share of the total chemical pulp production (in the U.S.A. about 10%), the potential of making yeast, proteins and other high-valued products from effluents is not to be underestimated. Reference is made to the production of about 100,000 tpa. of Masonex, a hemicellulose extract, derived from wood and f

f

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and c o n t a i n i n g pentose and hexose sugars, which i s used f o r c a t t l e f e e d i n g i n the United S t a t e s . There i s room f o r much l a r g e r q u a n t i t i e s of crude chemicals to be s u p p l i e d by the forest-based i n d u s t r y to the chemical i n d u s t r y f o r f u r t h e r processing. The question, however, i s who w i l l c a r r y out the necessary R & D work to achieve t h i s aim. I t i s s i g n i f i c a n t that the pulp/paper i n d u s t r y spends l e s s than 0.5$ of i t s turnover on R & D, whereas the s y n t h e t i c polymer i n d u s t r y spends about *f-5% of i t s o v e r a l l s a l e s on R & D. I t i s noteworthy t h a t chemical companies and j o i n t ventures o f chemical companies and forest-based companies occupy a prominent p o s i t i o n among l e a d i n g t a l l o i l f r a c t i o n a t o r s . In 1975* at the E i g h t h C e l l u l o s e Conference i n Syracuse, Mr. Benjamin Ward o f V/estvaco of crude t a l l o i l whic to about 900,000 tons i n 1973 (the r a t e o f the r e f i n e d t a l l o i l had increased t o 3θ}ί) said i n conclusion that: "In 10 to 20 years, i t may not be unreasonable to imagine t r e e s being grown s t r i c t l y as a source o f renewable chemicals which p l a y a major r o l e i n meeting the needs o f the chemical, as w e l l as the consumer, products industries. These remarks may sound as being of f u t u r o l o g i c a l nature to some North Americans, but, i n f a c t , i n some r e g i o n s , s p e c i a l i z e d t r e e s have been planted f o r t h i s purpose. In the case of rubber tree p l a n t a t i o n s i n Malaysia and i n other c o u n t r i e s , the tapped rubber i s the main product, and the t r e e when cut i s a by-product used mainly as f u e l (the attempts to u t i l i z e t h i s wood f o r pulp production have, on the whole, not met with success). Immediately when one c o n s i d e r s the rubber i n d u s t r y , the question o f s y n t h e t i c rubber comes i n t o one's mind. The development of the s y n t h e t i c rubber i n d u s t r y , p a r t l y f o s t e r e d by the s t r a t e g i c c o n s i d e r a t i o n s , e.g, during and s h o r t l y a f t e r the World War I I , has no doubt been a strong competitor against the n a t u r a l rubber i n d u s t r y . However, i t has r e s u l t e d i n a more e f f i c i e n t n a t u r a l rubber production, s t a n d a r d i z a t i o n o f i t s products b e n e f i c i a l to the n a t u r a l rubber i n d u s t r y , and due to the s y n t h e t i c rubber i n d u s t r y , the t o t a l consumption of rubber has increased c o n s i d e r a b l y (whereby tailor-made s y n t h e t i c rubbers have augmented t h i s market). I t i s d i f f i c u l t today to imagine the t o t a l requirements of the rubber c o n v e r t i n g i n d u s t r y , i n c l u d i n g the t y r e i n d u s t r y , being s u p p l i e d by the n a t u r a l rubber i n d u s t r y . Without the competition and s u p p l i e s by the s y n t h e t i c rubber i n d u s t r y , rubber as such would have never achieved the high tonnage consumption, and i n many cases would have p r i c e d i t s e l f out i n many a p p l i c a t i o n s . ,f

Co-operation and Competition, The r e c e n t l y published book "The Outlook f o r Timber i n the United S t a t e s " (U.S. Department of A g r i c u l t u r e , Forest S e r v i c e , J u l y , 197*0 r e f e r r e d to new

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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products of the paper and board i n d u s t r y with a l a r g e market, i n c l u d i n g milk c a r t o n s , and one has to say that milk cartons are p l a s t i c s coated cartons - an example o f co-operation between the pulp/paper and p l a s t i c s i n d u s t r i e s . M u l t i w a l l bags with p l a s t i c s l i n i n g s and many other examples of t h i s co-operation could be l i s t e d . Nearly 50?o o f the t o t a l paper and paperboard production f i n d a p p l i c a t i o n i n packaging. The major shortcomings of paper and paperboard i n packaging are that these products are not w a t e r - r e s i s t a n t , they absorb moisture, and t h e i r a i r , gas and vapour p e r m e a b i l i t y are very h i g h . Therefore, i n many packaging a p p l i c a t i o n s , a p r o t e c t i v e c o a t i n g by p l a s t i c s i s used to improve the f u n c t i o n a l p r o p e r t i e s o f paper and board. These shortcoming reasons f o r p l a s t i c s f i l m r e p l a c i n g paper and paperboard. Among recent developments, reference i s made to • p l a s t i c s paper (high and medium molecular weight h i g h - d e n s i t y p o l y ethylene f i l m ) which has been r e p l a c i n g , at an i n c r e a s i n g s c a l e , g l a s s i n e , greaseproof paper, vegetable parchment, and even MG k r a f t paper i n Europe and i n Japan. Shrink f i l m , and l a t e l y s t r e t c h f i l m , have been r e g i s t e r i n g a growing p e n e t r a t i o n of the market* In t e c h n i c a l a p p l i c a t i o n s , the replacement o f t i s s u e paper by polypropylene and p o l y e s t e r f i l m s i n the production of c a p a c i t o r s i s to be mentioned. In the f i e l d of w r i t i n g and p r i n t i n g papers and o f w a l l paper, spunbonded m a t e r i a l s (e.g. Tyvek), and p l a s t i c s f i l m based s y n t h e t i c papers (e.g. P o l y a r t and Yupo FP), have been competing against conventional papers. On the other hand, the development o f s y n t h e t i c pulp to be used as an a d d i t i v e to conventional woodpulp f o r making paper and board with improved f u n c t i o n a l p r o p e r t i e s (on conventional paper making machines) i s a new chapter o f co-operation between the t r a d i t i o n a l paper and the s y n t h e t i c polymer i n d u s t r i e s . According to conservative estimates ( l ) , the consumption of s y n t h e t i c pulp - on a worldwide b a s i s - d u r i n g the f i r s t h a l f o f the '80-ies w i l l amount to l80,000-250,000 tpa., with a h i g h growth r a t e i n the second h a l f o f that decade. The a d d i t i o n o f s y n t h e t i c pulp to the f u r n i s h a l s o r e s u l t s i n a b e t t e r drainage r a t e . Synthetic pulp has a l s o a good p o t e n t i a l market as a binder i n nonwovens production, and i n some a p p l i c a t i o n s outside the paper i n d u s t r y . At the present ACS Meeting, r e f e r e n c e s to co-operation and competition between the pulp/paper and s y n t h e t i c polymer indust r i e s have been made i n v a r i o u s p r e s e n t a t i o n s . Prof. Goldstein (2) s t r e s s e d the point that combinations o f s y n t h e t i c polymers and c e l l u l o s e i n the form o f blends, composites and c o a t i n g s , w i l l become i n r e a s i n g l y important i n meeting packaging (j>) and communication needs at low c o s t / e f f e c t i v e n e s s r a t i o . Composites, such as c e l l u l o s e or wood f i b r e r e i n f o r c e d p l a s t i c s , w i l l a l s o 1

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become more important. (A few years ago, Dr. A.A. Robertson (k), spoke o f encouraging p o s s i b i l i t i e s of the continued development of products based on combination o f s y n t h e t i c polymers and paper, and o f the growing importance o f polymer-paper composites.) Contrary to the growth o f woodpulp consumption f o r papermaking, the expensive h i g h - p u r i t y d i s s o l v i n g pulp i s produced to the extent o f only approximately 2 m i l l i o n tons per annum, and has been f a c i n g d e c l i n i n g markets. T h i s chemical c e l l u l o s e i s the s t a r t i n g m a t e r i a l f o r rayon and acetate f i b r e s , cellophane, c e l l u l o s e e s t e r p l a s t i c s and c e l l u l o s e ether gum, and P r o f e s s o r G o l d s t e i n f e l t that s i n c e much o f the present c e l l u l o s e t e c h nology i s h i g h l y energy i n t e n s i v e , the mere a v a i l a b i l i t y of c e l l u l o s e as a renewable resource w i l l not assure i n c r e a s e d u t i l i z a t i o n of c e l l u l o s i becomes favourable. The s i g n i f i c a n t point i s that cellophane f i l m which has been g r a d u a l l y r e p l a c e d by p l a s t i c s f i l m s , e.g. o r i e n t e d polypropylene f i l m , could somewhat r e t a r d i t s replacement by i n t r o d u c t i o n o f p l a s t i c s coated cellophane f i l m . According to a recent ICI study (5)» the U.K. energy requirements (expressed as tonnes o f o i l equivalent.,required as feedstock p l u s energy f o r the manufacturing) i n the case o f one m i l l i o n square metres o f packaging f i l m compare as f o l l o w s : Polypropylene f i l m Cellulose film

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P r o f e s s o r Simionescu (6) r e f e r r e d to i n v e s t i g a t i o n s aimed at o b t a i n i n g a favourable symbiosis between c e l l u l o s e and s y n t h e t i c polymers, the i n t r o d u c t i o n o f c e r t a i n polymers as mass a d d i t i v e s i n the paper production, and a l s o r e f e r r e d to the use o f c e r t a i n chemical f i b r e s i n t h i s f i e l d . At the same time, Simionescu r e f e r r e d to competition, i . e . s u b s t i t u t i o n o f t r a d i t i o n a l papers by s y n t h e t i c polymer products. Whole-tree u t i l i z a t i o n f o r pulp making has been arousing great i n t e r e s t , and i t i s to be expected that f u r t h e r developments i n t h i s f i e l d w i l l result i n - at least p a r t i a l - u t i l i z a t i o n of the high tonnages o f stumps, r o o t s , branches and f o l i a g e f o r making pulp (and, i n t h i s way, a l l e v i a t i n g the t h r e a t of f i b r e shortage) and/or f o r producing crude chemicals, and i n t h i s way improving the f i n a n c i a l r e t u r n s o f the forest-based concerns, p a r t i c u l a r l y as the cost o f woodlands has been r i s i n g at a very high r a t e , i n f l u e n c i n g the cost o f forest-based products (the index o f cost per acre o f prime Southern woodland, t a k i n g i t s cost i n 1955 as 100, has increased from 182 i n 1965 to 1,367 in 1975). However, s t u d i e s on the u t i l i z a t i o n o f stump wood i n pulp production by the I n s t i t u t e o f Paper Chemistry, Appleton (7)i have shown that stump wood pulp can be expected to be i n f e r i o r i n most p h y s i c a l p r o p e r t i e s , other than f o l d i n g endurance, when compared with a s i m i l a r pulp made from conventional pine c h i p s . The question a r i s e s whether i t would be economically v i a b l e to

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improve the p r o p e r t i e s o f k r a f t paper from stump wood pulp ( t e n s i l e breaking l e n g t h , t e a r s t r e n g t h , e t c . ) by i n c o r p o r a t i n g i n t o the f u r n i s h a s m a l l amount o f s y n t h e t i c f i b r e s . Reference i s made t o the t r i a l s being c a r r i e d out a t present i n West Germany o f making k r a f t paper (with improved p r o p e r t i e s f o r cement sacks) from c o n v e n t i o n a l pulp p l u s a s m a l l p r o p o r t i o n o f nylon s h o r t - c u t f i b r e s . General Comments (Feedstock, Energy Consumption, Markets, I n f l a t i o n ) . The crude o i l s i t u a t i o n i s o f great importance t o both i n d u s t r i e s . The pulp/paper i n d u s t r y i s a l a r g e user o f energy, r e q u i r i n g i n the u n i t e d S t a t e s about three b a r r e l s o f o i l f o r the p r o d u c t i o n o f one ton o f paper, and the p l a s t i c s i n d u s t r y has been u s i n g crude o i o i l into p l a s t i c s finishe Compared w i t h the world p r o d u c t i o n o f about IkO m i l l i o n tons o f paper and paperboard per annum, the annual production o f p l a s t i c s i s about h$ m i l l i o n tons, o f which roughly 15 m i l l i o n tons f i n d a p p l i c a t i o n i n packaging, i n c l u d i n g b o t t l e s , c o n t a i n e r s and a l s o ! f i l m s . However, one ton o f p l a s t i c s f i l m - depending on the j polymer i n v o l v e d and the a p p l i c a t i o n - r e p l a c e s between 2 and 3 tons o f paper. The American Petroleum I n s t i t u t e assessed r e c e n t l y that "proved reserves o f crude o i l c o u l d be o f the order o f 98,000 m i l l i o n tonnes, and the annual world o i l consumption was r e c e n t l y e s t i ­ mated a t l e s s than 2,800 m i l l i o n tonnes i n 1973 and 197^ (BP S t a t i s t i c a l Review). The t o t a l consumption o f the world petrochemical i n d u s t r y accounts f o r about 5Λ> o f the g l o b a l o i l consumption, and the bigger share o f the petrochemical i n d u s t r y ' s requirements i s used f o r the p r o d u c t i o n o f f e r t i l i z e r s . Only 2% o f the world o i l consumption are used f o r making p l a s t i c s m a t e r i a l s . As | p l a s t i c s m a t e r i a l s belong t o the h i g h e s t upvalued products d e r i v e d from crude o i l , i t i s t o be expected that the tonnages j r e q u i r e d by t h i s i n d u s t r y w i l l be always a v a i l a b l e , whereas t e c h n o l o g i c a l developments w i l l l e a d t o savings o f o i l consump­ t i o n i n many other f i e l d s due t o the growing r e a l i s a t i o n that j j u s t burning o i l i s an obsolete p r a c t i c e . The growing i n t e r e s t o f i n t e r n a t i o n a l o i l companies i n downstream o p e r a t i o n s (production o f monomers, polymers and even p l a s t i c s products) and, a t the same time, t h e i r involvement i n the develop­ ment o f other energy sources, i s a n o t i c e a b l e p o i n t e r f o r the future. With f i n d i n g o f new o i l r e s e r v e s , i n c l u d i n g those outside the Middle E a s t , and t h e i r b e t t e r u t i l i z a t i o n , together with the development o f other energy sources, which were uneconomic a t the o i l p r i c e o f ^ 2 per b a r r e l , but may be v i a b l e a t present crude o i l p r i c e s , the danger o f o i l p r i c e s i n c r e a s i n g i n future at a r a t e above the o v e r a l l i n f l a t i o n r a t e i s not t o be envisaged, provided that the s i t u a t i o n i s faced squarely by governments and i n d u s t r y i n an e f f e c t i v e manner. 1

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The energy consumption i n production o f p l a s t i c s together with the o i l used as feedstock, i s lower than the energy consumption i n the production o f paper and of many other products. According to the NATO Report (8), the t y p i c a l energy content o f p l a s t i c s products i s 10 megajoules/kg. as against 25 megajoules/kg. i n the case of paper products. According to the a l r e a d y mentioned ICI study, the U.K. energy requirements (expressed i n tons o f o i l e q u i v a l e n t i n c l u d i n g feedstock and energy) f o r the manufacture of 1 m i l l i o n f e r t i l i s e r sacks made from low-density polyethylene f i l m amount to V70, as a g a i n s t 700 when these sacks are made from k r a f t paper. The d i f f i c u l t y o f comparing the energy requirements of v a r i o u s products i s p a r t l y due to the f a c t that i n some cases only s p e c i f i c s e c t o r s of the to. The high energy consumption of the pulp and paper i n d u s t r y i s w e l l known. The recent "Fuel Survey" by the American Pulpwood A s s o c i a t i o n , Washington, (published 1975) says that i n 197^ pulpwood h a r v e s t i n g r e q u i r e d an average o f 5*16 gallons of fuel - either gasoline or d i e s e l - to harvest a cord o f pulpwood and move i t from the stump to a c o n c e n t r a t i o n point or m i l l by truck. This survey, r e f e r r i n g to the continuous trend towards greater mechani s a t i o n , says that " i t appears d o u b t f u l that the average r a t e o f f u e l consumption f o r h a r v e s t i n g pulpwood can be reduced". It would be an i n t e r e s t i n g e x e r c i s e to c a l c u l a t e the a d d i t i o n a l f u e l requirements, i n c l u d i n g a d m i n i s t r a t i o n of f o r e s t s p r i o r to the h a r v e s t i n g o f pulpwood. A l l these energy requirements i n the pulp/paper i n d u s t r y (together with those i n the a c t u a l pulp and papermaking) c l e a r l y show that the a c t u a l production c o s t s of c e l l u l o s i c paper r e f l e c t d i r e c t l y the changes o f the crude o i l p r i c e s . A number o f s t u d i e s have been made on the i n f l u e n c e of changes of crude o i l p r i c e s on the production c o s t s of p l a s t i c s m a t e r i a l s and p l a s t i c s products. The above mentioned ICI study r e f e r s to the e f f e c t of crude o i l increased p r i c e s on downstream operations, and i l l u s t r a t e s the d i l u t i o n of the crude o i l cost component i n the production c o s t s of monomers, polymers, and f i n i s h e d , goods. The increase o f crude o i l p r i c e by 300% r e s u l t s i n an increase o f the p r i c e of ethylene by 200%, polyethylene by 100%, and o f polyethylene bags by 30%. In the case o f propylene, the increase was even lower, namely l80%, and of polypropylene by only 70%. The f a c t i s that d e s p i t e the high i n c r e a s e s o f crude o i l p r i c e s since the end o f 1973» p l a s t i c s have not l o s t (apart from a few e x c e p t i o n a l cases) t h e i r competitive strength and have continued to penetrate the paper markets. The present r e c e s s i o n has r e s u l t e d i n the lowering of paper p r i c e s i n v a r i o u s European markets. In West Germany, the biggest papermaking country of Europe, the wholesale p r i c e s o f some packaging papers i n September, 19751 were about 14% lower than i n September, 197*+. Some types of paperboard r e g i s t e r e d an even greater drop t

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in prices. All indications are that as soon as the market con­ ditions improve, the prices of paper will increase above the September, 1974, level, reflecting the increased production costs. It is anticipated that in boom conditions, paper prices will have to increase at a higher rate than the overall inflation rate, in order to make papermaking a viable proposition. Polymer and plastics prices are expected to increase at a rate lower than the overall inflation rate. Among the reasons for this are the technological developments taking place in this industry. A number of examples in the production of polymers and in the plastics processing industry, which have resulted in lowering the production costs during the last few years, could be cited. Whereas a few years ago, a 60 mm. extruder had a production rate of about 30-35 kg./h f plastic extruder of the same size produc of the same thickness. The further penetration by plastics of the conventional paper and board markets is to be expected, and, at the same time, new products made from cellulosic pulp plus synthetic polymers will secure considerable markets, representing a growing co­ operation between these two industries. Literature Cited (1) Wolpert, Vladimir Μ., "Plastics and the Paper Industry", p. 25, Wolpert & Jones (Studies) Ltd., London, 1975. (2) Goldstein, Irving S., "The Place of Cellulose under Energy Scarcity", presentation at the ACS Centennial Meeting, New York, 1976. (3) Jones, Allen, and Wolpert, Vladimir Μ., "Composite Materials for Packaging", 235 pp., Wolpert & Jones (Studies) Ltd., London, 1976. (4) Robertson, Α.Α., "Modification of the Mechanical Proper­ ties of Paper by the Addition of Synthetic Polymers", presentation at the International Symposium "The Fundamental Properties of Paper Related to its Uses", organized by the British Paper and Board Makers' Association, Cambridge (England), 1973. (5) ICI Ltd., "The Competitiveness of of LD ΡΕ, PP and PVC After the 1973 Oil Crisis: The ICI View", ICI, London, 1974. (6) Simionescu, Cristofor I., "The Relation 'CellulosePaper', Options and Developments", pre-print of the ACS Centennial Meeting, New York, 1976. (7) Peckham, John R., and McKee, Robert C., "Pulp & Paper", (1975), Volume 49, (Number 14), pp. 53-55. (8) NATO Report, "Technology of Efficient Energy Utilization'! NATO, Brussels, 1973.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

15 The Pulp Mill of the Future—Environmental and Raw Material Considerations BENGT LEOPOLD SUNY College of Environmental Science and Forestry, Syracuse, NY

The founding of the American Chemical Society in 1876 coincides almost exactly per industry. Before th tively small scale from an expensive and increasingly scarce raw material, cotton rags. Then, during a very short time span, the picture changed drastically with the advent of a number of processes for the production of a new raw material, wood pulp. The f i r s t of these was the so-called groundwood process, a mechanical process which was invented in 1844 but introduced to the U.S. in 1867. This development rapidly increased the production of newsprint, as indicated by the fact that the price dropped from 14¢ to 2¢/lb in less than 25 years. Nevertheless, it can be argued that the so-called chemical pulping processes had the greatest impetus in making the pulp and paper industry the giant it is today. One of these, the sulfite process, was invented by the American chemist, Tilghman, in 1867 although the f i r s t sulfite pulp mill was built in Sweden in 1874. The other important chemical process, the kraft process, is of a slightly later date, invented in 1884 with the f i r s t mill dating from 1891. However, it had its roots in the so-called soda process, which was developed before 1860. So we see that within only a few years, a revolutionary change had taken place in the industry (1) The driving force behind these developments was unquestionably the rapidly increasing demand for paper in a society that was fast becoming industrialized. This can be clearly seen in Figure 1, which shows the increase in per capita consumption of paper for the past 100 years or so. Needless to say, the basic assumption behind this vigorous development was that there would always be an unlimited supply of wood, as well as chemicals, water and energy. Here we are, 100 years later, and we know now that there is no such thing as an unlimited supply of anything, except possibly dire predictions of impending disaster. Because of this, we are again facing drastic changes in the pulp and paper industry, just as we were 100 years ago, but for almost exactly the opposite 239 In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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reasons. We can no longer expect t o o b t a i n any o f our raw mat e r i a l s as e f f o r t l e s s l y as i n the p a s t , and t h i s i s p a r t i c u l a r l y t r u e f o r water and energy. A r e l a t i v e l y new f a c t o r has a l s o entered the p i c t u r e - concern f o r the environment. Because of the tremendous e f f o r t s i n t h i s a r e a , the pulp and paper i n d u s t r y has been saddled with a number of new c o n s t r a i n t s , imposed and otherwise, which has made i t even more d i f f i c u l t f o r the i n d u s t r y to o b t a i n i t s raw m a t e r i a l e c o n o m i c a l l y . A l l o f these events have i n c r e a s e d the consumption o f t h a t most important raw m a t e r i a l of a l l - c a p i t a l . C a p i t a l f o r new c o n s t r u c t i o n , c a p i t a l f o r p o l l u t i o n abatement, c a p i t a l f o r mode r n i z a t i o n of out-dated equipment - requirements f o r a l l o f these have skyrocketed. For example, i t now c o s t s $240,000/ d a i l y ton t o b u i l d a new bleached k r a f t m i l l {2); t h i s amounts to the enormous sum o t y p i c a l s i z e . And t h i capita g c r e a s i n g l y hard t o r a i s e . It i s c l e a r , then, t h a t the changes t h a t w i l l be needed i n the next s e v e r a l decades l i e i n the d i r e c t i o n o f b e t t e r u t i l i z a t i o n o f wood, w i t h l e s s use o f chemicals and energy and l i t t l e or no d i s c h a r g e o f waste products, a l l a t a lower c a p i t a l c o s t than a t present. T h i s i s a very t a l l order indeed! Today, I am not going t o indulge i n p r e d i c t i o n s concerning our r e l a t i v e success i n these v a r i o u s endeavors but r a t h e r d i s cuss a number o f r e s e a r c h developments t h a t may o f f e r s o l u t i o n s to some of these problems i n the n o t - t o o - d i s t a n t f u t u r e . Here, I s h a l l c o n f i n e my remarks t o a d i s c u s s i o n o f the pulp m i l l . Many i n n o v a t i o n s t h a t l e a d to raw m a t e r i a l c o n s e r v a t i o n o r p o l l u t i o n abatement are a l r e a d y upon us and do not belong t o the f u t u r e . One i n t e r e s t i n g such development i s whole-tree p u l p i n g , i . e . , p u l p i n g a l l o f the t r e e , i n c l u d i n g branches, twigs, bark, and f o l i a g e . T h i s i s being p r a c t i c e d today t o an i n c r e a s i n g degree (3-5). Another i n n o v a t i o n i s the concept o f the completely c l o s e d pulp m i l l , where e v e r y t h i n g , i n c l u d i n g b l e a c h e f f l u e n t s , i s r e c y c l e d and reused. Such a pulp m i l l , based on the k r a f t process, i s now being c o n s t r u c t e d a t Thunder Bay, O n t a r i o and i s based on the p i o n e e r i n g work of Rapson and h i s co-workers ( 6 , 7 ) . T h i s process w i l l , of course, completely e l i m i n a t e water p o l l u t i o n problems, and i t w i l l undoubtedly t u r n out t o be one of the most important developments o f t h i s p e r i o d . However, r a t h e r than dwell on processes a l r e a d y on the drawing board o r i n o p e r a t i o n , I t h i n k i t would be more f i t t i n g on an o c c a s i o n such as t h i s to t a l k about the f u t u r e . For the next 30 minutes or so, I i n t e n d t o l e t my imagination loose and conj u r e up a p i c t u r e of the pulp m i l l o f the f u t u r e , as seen from the r e s e a r c h e r ' s p o i n t o f view. T h i s p i c t u r e w i l l be o f the imp r e s s i o n i s t i c v a r i e t y , with few d e t a i l s , somewhere between dream and r e a l i t y . I s h a l l sketch a number of p o s s i b l e schemes, not only i n the l i g h t o f what we know today but a l s o i n terms of what we have t o l e a r n tomorrow i f we want to move from dream to

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reality. My d i s c u s s i o n w i l l concentrate on two s p e c i f i c areas t h a t I t h i n k show the g r e a t e s t promise f o r the f u t u r e : 1) o x y g e n - a l k a l i p u l p i n g , which appears to have the potent i a l of being one of the major commercial p u l p i n g methods i n the r e l a t i v e l y s h o r t term, and 2) expansion of the use o f mechanical pulps t o a l l grades o f paper and board now r e q u i r i n g chemical pulps, a development of enormous p o t e n t i a l but probably o n l y i n the r e l a t i v e l y long term. OXYGEN PULPING Early

Research

In the o x y g e n - a l k a l i p u l p i n g method, wood i s d e l i g n i f i e d with oxygen i n the presence o f a l k a l i . One of the advantages of t h i s process i s t h a t i t leads to p r a c t i c a l l y o d o r - f r e e p u l p i n g . A l s o , r e c y c l i n g and recovery of e f f l u e n t s i s g r e a t l y s i m p l i f i e d . In a d d i t i o n , o x y g e n - a l k a l i pulps are much l i g h t e r i n c o l o r than conventional k r a f t pulps and a l s o much e a s i e r to b l e a c h , thus having a p o t e n t i a l f o r s i m p l i f i e d bleach p l a n t s and l e s s use o f chemicals. Not s u r p r i s i n g l y , t h i s process i s now the s u b j e c t of i n t e n s i v e research e f f o r t s i n many p a r t s of the world (8-15). U n f o r t u n a t e l y , the o x y g e n - a l k a l i pulping process has a number of very s e r i o u s drawbacks. Perhaps the most fundamental o f these i s i t s heterogeneity. Since the r e a c t i o n i n v o l v e s a gas phase, oxygen, and the l a t t e r has a f a i r l y low s o l u b i l i t y i n the l i q u i d phase, aqueous a l k a l i , p e n e t r a t i o n of the wood c h i p i s a c r i t i c a l problem. In most oxygen p u l p i n g schemes to date, t h i s has been s o l v e d by p u l p i n g i n two or more stages. In the f i r s t stage, the wood i s p a r t i a l l y d e l i g n i f i e d i n aqueous a l k a l i , with or without the presence o f oxygen. The p a r t i a l l y pulped c h i p s are then f i b e r i z e d and the p u l p i n g completed with oxygen and a l k a l i , t y p i c a l l y a t 140-150°C and 100-150 p s i 02- A t y p i c a l l a b o r a t o r y scheme i s shown i n Figure 2. Using a process of t h i s type, i t i s p o s s i b l e to produce pulps with s t r e n g t h p r o p e r t i e s comparable to those o f k r a f t pulps, a t l e a s t from hardwood (Table I ) . Softwood presents more of a c h a l l e n g e , and u s u a l l y there i s a problem with t e a r s t r e n g t h and f o l d i n g endurance (Table I I ) . On the other hand, i t must be s a i d t h a t oxygen pulps are s u p e r i o r to k r a f t pulps i n some other r e s p e c t s . For i n s t a n c e , they are always b r i g h t e r i n c o l o r than k r a f t pulps (Table I I I ) and they beat more e a s i l y ( F i g u r e 3). I w i l l say more about t h i s l a t e r . The pulps are a l s o much e a s i e r to b l e a c h , as we w i l l see i n a moment.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

242

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

( 0 , lOpsi)

DISC

2

WOOD CHIPS

16%

NaOH

ON WOOD I70°C

SEMICOOKED, CHIPS

Figure 2. Two-stage

REFINER

( 0 , 140 psi) 2

DEFIBERIZED CHIPS

oxygen-alkali

pulping

6%

NaOH

ON WOOD 150° C

scheme

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

PULP.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

Freeness, CS, ml Bulk, c c / g Burst F a c t o r Tear F a c t o r MIT F o l d i n g Endurance Breaking Length, m Zero Span Breaking Length, m Energy t o Break, cm-Kg Bonding Index, % Stretch, % S c a t t e r i n g C o e f f i c i e n t , sq cm/g

295 1.18 100.0 80 2160 10,130 16,090 1.81 62.9 2.2 113

305 1.21 105.5 81 1640 11,210 16,460 1.96 68.1 2.3 138

--

+ 5.5 + 1.2 -24.1 +10.6 + 2.3 + 8.3 + 8.3

—

Table I. Comparison o f Strength C h a r a c t e r i s t i c s o f Unbleached White B i r c h Oxygen and K r a f t Pulps Unbleached K r a f t Pulp Unbleached Oxygen Pulp Cook No. DJ-17 1 s t Stage Cook No. DJ-16 Elrepho B r i g h t n e s s , 26.5% 2nd Stage Cook No. DJ-16C CED V i s c o s i t y , 34.4% cp CED V i s c o s i t y , 19.9% cp % Difference Kappa No. 18.0 Kappa No. 8.5 K r a f t Pulp Y i e l d , % - 49 Y i e l d , % - 49 Values = 100% 510 495 Freeness, CS, ml 1.26 1.24 Bulk, c c / g 108.0 +17.9 91.6 Burst F a c t o r 94 + 3.3 91 Tear F a c t o r 1350 +19.5 1130 MIT F o l d i n g Endurance 10,890 + 9.7 9930 Breaking Length, m 16,570 - 0.3 16,620 Zero Span Breaking Length, 2.16 +18.7 1.82 Energy t o Break, cm-Kg 65.7 +10.0 59.7 Bonding Index, % 2.6 2.3 Stretch, % 164 150 S c a t t e r i n g C o e f f i c i e n t , sq cm/g

244

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

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In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

47.3 11.7

45.0

6.0

Yield, %

Kappa Number

74.5

83.0

Bleached*

9

*3% C10 , one-stage

46.2

56.6

Unbleached

Brightness, %

Oxygen

Oxygen

40.5

29.2

20.7

47.5

Kraft

37.4

14.0

48.2

Oxygen

20.2

26.0

48.1

Kraft

38.1

19.8

51.0

Oxygen

Kappa Number, B r i g h t n e s s , and B l e a c h a b i l i t y o f Spruce Pulps

Table I I I

246

TEXTILE

AND PAPER

CHEMISTRY

AND

TECHNOLOGY

But f i r s t I would l i k e to p o i n t out t h a t we may be making a mistake by c o n t i n u i n g to use k r a f t pulp p r o p e r t i e s as our s t a n dard. Even though k r a f t pulps have served us w e l l and w i l l cont i n u e to do so f o r a long time, we do not need t h e i r high s t r e n g t h f o r a l a r g e number o f our paper grades, w h i l e i n many cases, i t would be a great advantage to get away from hard-tobeat and hard-to-bleach pulps. Maybe we ought t o stop c o n s i d e r ing oxygen pulps as s u b s t i t u t e s f o r k r a f t and e v a l u a t e them f o r what they are - a new type of product. Simplification The c a p i t a l c o s t o f a pulp m i l l based on the m u l t i s t a g e oxygen p u l p i n g process ca very complex and c a p i t a chemical stages o f w i d e l y d i f f e r e n t temperature and other r e a c t i o n c o n d i t i o n s , with a d e f i b e r i z i n g step i n between, o b v i o u s l y a very c o s t l y p r o p o s i t i o n . What we have to look f o r now i s s i m p l i f i c a t i o n . A f t e r a l l , r e l a t i v e s i m p l i c i t y i s one of the main advantages of the c u r r e n t k r a f t process. I f we c o u l d e l i m i n a t e one o f the chemical s t a g e s , we would move i n the r i g h t d i r e c t i o n . One way t o do t h i s would be t o s t a r t w i t h d e f i b e r i z e d wood (J3). T h i s would e l i m i n a t e most of the p e n e t r a t i o n problems and would o f f e r the p o s s i b i l i t y of a uniform r e a c t i o n . One i n t r i g u i n g such raw m a t e r i a l i s s o - c a l l e d thermomechanical pulp (TMP). T h i s i s pulp obtained from wood using p u r e l y mec h a n i c a l means. The f i b e r i z a t i o n occurs a t e l e v a t e d temperatures and pressures so as to s o f t e n the i n t e r c e l l u l a r l i g n i n and hemic e l l u l o s e and make i t p o s s i b l e to separate the f i b e r s with a m i n i mum o f damage to the c e l l w a l l . C u r r e n t l y , TMP i s being used to an i n c r e a s i n g degree i n the manufacture o f newsprint and other low-cost grades of paper (16). More about t h a t l a t e r . Table IV shows l a b o r a t o r y r e s u l t s of oxygen p u l p i n g of TMP from white oak, a hardwood. The s t r e n g t h p r o p e r t i e s o f the pulp are comparable to those obtained f o r c h i p s , except f o r t e a r s t r e n g t h . We b e l i e v e t h i s i s mostly a q u e s t i o n of damage i n the f i b e r i z a t i o n s t e p . S i m i l a r c o n c l u s i o n s can be drawn from r e s u l t s with Norway spruce, a softwood ( F i g u r e s 4 and 5 ) . We can conc l u d e , then, t h a t a t l e a s t f o r some grades, oxygen p u l p i n g can be performed i n one chemical stage, which w i l l g r e a t l y reduce the complexity and c a p i t a l c o s t o f the p l a n t . A schematic o f such a m i l l i s shown i n Figure 6. Obviously, a f u r t h e r step i n the r i g h t d i r e c t i o n would be t o e l i m i n a t e the f i b e r i z i n g step and do the p u l p i n g i n one chemical o p e r a t i o n (14), much as today's k r a f t p u l p i n g i s c a r r i e d out. One way of accomplishing t h i s would be by p u l p i n g with s i m u l t a neous, very vigorous a g i t a t i o n . P r e l i m i n a r y s t u d i e s i n our labor a t o r y have shown t h a t such an approach i s f e a s i b l e . We have, f o r i n s t a n c e , produced a one-stage hardwood o x y g e n - a l k a l i pulp

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

15.

Pulp

LEOPOLD

Mill of the

O

Future

500

IpOO 1,500 REVOLUTIONS

PFI

Figure

3. Comparison pulp; CS.

247

of oxygen-alkali

2,000

and

Kraft

Table IV Comparison of White Oak Oxygen Pulp: Oxygen, TMP

TMP vs. Chips Oxygen, Chips 2nd Stage 1st Stage

Pulping C o n d i t i o n s 20

20

4

Oxygen Pressure, p s i

140

10

140

Temperature, °C

165

165

150

Time, h r

1

2

1

Pulps Yield, %

45.7

48.7

Brightness, %

70.6

54.6

Refining

PFI

PFI

CSF, ml

580

550

.592

.680

59

55

7140

6900

NaOH, %

3 Density, g/cm Burst F a c t o r Breaking Length, m Tear Factor

117

'

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

248

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

2001

(a) |,50| LL

< i— I00|

50'

0.6

0.7 DENSITY,

0.8 g/cm 3

(b)

Il0|

Ε CD

Ο

S Figure pulping spruce; (b)

5. Comparison of oxygen-alkali of chips and TMP from Norway (a) tear factor vs. sheet density; breaking length vs. tear factor

or 0 0

, 6 50

100

150 200 TEAR FACTOR

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

250

15.

LEOPOLD

Pulp Mill of

the

Future

249

o f acceptable q u a l i t y (Table V). However a number o f very d i f f i c u l t e n g i n e e r i n g problems would have to be s o l v e d . Table V Comparison o f One-Stage Oxygen-Alkali Pulp with K r a f t Pulp, both from Sugar Maple Oxygen-Alkali Kraft Yield, % CS Freeness, ml Density, g/cm Burst F a c t o r Breaking Length, m Tear F a c t o r Brightness, % 3

48.3 365 0.680

49.7 390 0.642

8,250 75 46.1

8,700 71 31.5

B l e a c h i n g with Ozone I mentioned the ease o f b l e a c h i n g oxygen pulps. T h i s i s t r u e f o r conventional b l e a c h i n g systems, such as the 5-stage chlorine-alkali extraction-chlorine dioxide-alkali extractionc h l o r i n e d i o x i d e (CEDED) sequence commonly used. But even more i n t e r e s t i n g might be the d i s c o v e r y t h a t oxygen pulps are p a r t i c u l a r l y s u i t e d f o r ozone b l e a c h i n g . Ozone has not been used comm e r c i a l l y as a b l e a c h i n g agent y e t (17), but i t i s o f g r e a t i n t e r e s t because i t leaves no chemical r e s i d u e and as such presents no water p o l l u t i o n problem. The main d i f f i c u l t y i s the c o s t o f ozone, which i s l a r g e l y t i e d i n w i t h the c o s t o f e l e c t r i c i t y . E f f o r t s must now be made to i n c r e a s e the e f f i c i e n c y o f ozone gene r a t i o n so as to b r i n g down the power c o s t . In a d d i t i o n , ozone i s not as s e l e c t i v e as one would l i k e , and e x c e s s i v e degradation and s t r e n g t h l o s s can r e s u l t . In the case o f oxygen pulps, t h i s problem appears t o be minimized. The r e s u l t s i n Table VI show t h a t a bleached pulp e q u i v a l e n t or s u p e r i o r to k r a f t bleached pulp can be obtained from hardwood, such as b i r c h , using the oxygen-ozone combination. With softwood (Table V I I ) , the r e s u l t s are not q u i t e as s a t i s f a c t o r y . A p p l i c a t i o n i n the M i l l We have now the makings o f a very i n t r i g u i n g pulp m i l l of the f u t u r e ( F i g u r e 7). T h i s would be a m i l l where the o n l y chemi c a l s used would be a l k a l i and oxygen. I t would be a m i l l where excess oxygen from the bleach p l a n t (ozone i s c a r r i e d as 3-4% mixture with oxygen) i s piped back to the pulp m i l l . I t would be a m i l l where b l e a c h i n g would be done a t room temperature and

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

2

Freeness, CS, ml Bulk, cc/g Burst F a c t o r Tear F a c t o r MIT F o l d i n g Endurance Breaking Length, m Zero Span Breaking Length, m Energy t o Break, cm-Kg Bonding Index, % Stretch, % S c a t t e r i n g C o e f f i c i e n t , cm /g

Freeness, CS, ml Bulk, c c / g Burst F a c t o r Tear F a c t o r MIT F o l d i n g Endurance Breaking Length, m Zero Span Breaking Length, m Energy t o Break, cm-Kg Bonding Index, % Stretch, % 2 S c a t t e r i n g C o e f f i c i e n t , cm /g 320 1.21 90.1 98 1280 9285 15,960 1.77 58.2 2.5 166

280 1.18 99.8 79 1780 10,060 14,520 1.90 69.3 2.4 152

3

Bleached K r a f t Pulp (CEDED) Bleached Oxygen Pulp ( 0 ) Elrepho B r i g h t n e s s , 85.4% Elrepho B r i g h t n e s s , 81.5% CEP V i s c o s i t y , 10.5% cp CEP V i s c o s i t y , 29.8% cp 500 520 1.27 1.27 96.5 85.0 98 111 860 1040 9890 8800 15,600 15,040 1.93 1.65 63.4 58.5 2.5 2.5 196 192

-

+10.8 -19.4 +39.1 + 8.4 - 9.0 + 7.3 +19.1 -

-

-

—

-

+13.5 -11.7 -17.3 +12.4 + 3.7 +17.0 + 8.4

-

% Oifference K r a f t Pulp Values = 100%

Table VI Comparison o f C o n v e n t i o n a l l y Bleached K r a f t w i t h Ozone Bleached Oxygen Pulp, Both from White B i r c h

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

Freeness, CS, ml Bulk, c c / g Burst F a c t o r Tear F a c t o r MIT F o l d i n g Endurance Breaking Length, m Zero Span Breaking Length, m Bonding Index, % Stretch, % 2 S c a t t e r i n g C o e f f i c i e n t , cm /g

2

300 1.33 114 114 1,470 11,380 18,020 63.1 2.7 197

310 1.42 81.6 119 930 10,100 18,330 55.1 3.0 285

-

-

+ 4.4 -36.7 -11.2 + 1.7 -12.7

-28.4

Table V I I . Comparison o f C o n v e n t i o n a l l y Bleached K r a f t with Ozone Bleached Oxygen Pulp, Both from Spruce 3-Stage Bleached K r a f t Pulp Bleached Oxygen (CEDED) Pulp (O3EO3) % Difference Elrepho B r i g h t n e s s , 81.6% Elrepho B r i g h t n e s s , 80.0% K r a f t Pulp CEP V i s c o s i t y , 16.0 cp CEP V i s c o s i t y , 6.2 cp Values = 100% 480 500 Freeness, CS, ml 1.49 1.40 Bulk, c c / g 86.0 -27.7 119 Burst F a c t o r 131 +13.9 115 Tear F a c t o r 950 -28.0 1,320 MIT F o l d i n g Endurance 9,720 -12.7 11,130 Breaking Length, m 17,980 - 9.3 19,830 Zero Span Breaking Length, m 54.1 - 3.6 56.1 Bonding Index, % 2.9 2.9 Stretch, % 178 292 S c a t t e r i n g C o e f f i c i e n t , cm /g -

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

252

UNBLEACHED PULP CHIPS

Figure 6.

Flowsheet

for oxygen-alkali

pulping

of TMP

o

2

ψ OZONE GENERATOR

ALKALI

CHIPS

THERMOMECHANICAL REFINER

TO DEFIBERIZATION

Figure

7.

Flowsheet

OXYGEN

for manufacture

RECOVERY

PULPING

of ozone bleached

OZONE BLEACHING

oxygen-alkali

pulp from

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TMP

15.

LEOPOLD

Pulp Mill of the

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atmospheric pressure i n a few minutes. I t would be a m i l l where the v a r i o u s streams from the p u l p i n g and b l e a c h i n g p l a n t would c o n t a i n nothing but o r g a n i c matter and a l k a l i , and thus they could a l l go t o a recovery furnace to recover the only i n o r g a n i c chemical needed - a l k a l i . I t would be a m i l l where consumption of b e a t i n g energy would be reduced c o n s i d e r a b l y s i n c e oxygen pulps beat very r a p i d l y . I n c i d e n t a l l y , an o x i d a t i v e treatment o f conventional k r a f t pulps can have much the same e f f e c t , as shown i n Table V I I I . As you can see, a l i g h t treatment of k r a f t pulp with o x y g e n - a l k a l i leads to a t o t a l r e d u c t i o n i n b e a t i n g energy o f 50-70%. Some a d d i t i o n a l energy, o f course, i s consumed in the o x i d a t i o n treatment, but a rough estimate i n d i c a t e s t h a t t h i s amounts t o no more than 1/3 o f the t o t a l , so we have a net savings of 35-50%. It i s clear that thi f e a t u r e s . Yet, i t i s f a r from p r a c t i c a l r e a l i z a t i o n , given t o day's s t a t e o f the a r t . Much r e s e a r c h i s needed i n the next few y e a r s , e s p e c i a l l y i n the e n g i n e e r i n g aspects o f the process. MECHANICAL PULPING I f the f u t u r e p o t e n t i a l o f oxygen p u l p i n g i s i n t r i g u i n g , the f u t u r e p o t e n t i a l o f mechanical p u l p i n g i s o u t r i g h t mind-boggling. Or, as i t was b i l l e d a t l a s t year's TAPPI I n t e r n a t i o n a l Mechanical Pulping Conference i n San F r a n c i s c o : i t i s a g o l d mine, and a neglected one a t t h a t . A t t h a t conference, Underhay (18) made an eloquent p l e a f o r g r e a t l y i n c r e a s e d e f f o r t s to u t i l i z e mechanical pulp i n a l l or most paper grades. I f t h i s c o u l d indeed be accomp l i s h e d , we would almost double the p r o d u c t i o n from a given amount of wood, and chemical consumption and water and a i r p o l l u t i o n would be kept to a minimum. Is t h i s kind of papermaking r e v o l u t i o n r e a l l y f e a s i b l e ? Bef o r e attempting t o answer t h i s q u e s t i o n , l e t us f i r s t examine some o f the reasons why today's mechanical pulps tend t o be uns a t i s f a c t o r y as raw m a t e r i a l f o r many, i f not most, paper products. The d e f i c i e n c i e s l i e e s s e n t i a l l y i n two a r e a s : appearance ( c o l o r ) and mechanical performance. Color The appearance of the product i s marred by i t s c o l o r which i s g e n e r a l l y considered to be too dark and too u n s t a b l e f o r use i n anything but newsprint and other products designed f o r a very s h o r t p e r i o d of use. I n c i d e n t a l l y , t h i s might be a good o p p o r t u n i t y t o p o i n t out t h a t the determination o f what c o n s t i t u t e s good q u a l i t y i n terms o f c o l o r i s a t best a r b i t r a r y , and there i s a growing f e e l i n g i n the i n d u s t r y t h a t the e s c a l a t i o n i n paper b r i g h t n e s s t h a t we have witnessed through the y e a r s i s not j u s t i f i e d i n terms o f end-use q u a l i t y , and i s an unnecessary and maybe even harmful development.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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Table VIII E f f e c t o f Oxygen-Alkali Treatment o f K r a f t Pulp on Degree of Beating Required to Reach a Given Strength Value n

„i .

,

n a l Dlllr 0 n g i n a 1 P u 1 p

Kappa No.

No. R e v o l u t i o n s PFI M i l l

Oxygen-Alkali Treated Pulp No. R e v o l u t i o n s PFI M i l l

Reduction No. R e v o l u t i o n s %

39.7

500

150

70

71.3

1200

350

71

95.2

1700

725

57

Figure

8.

Sequence

for the reaction of creosol wtih alkaline peroxide

hydrogen

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

15.

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I n t e r e s t i n g l y , one of the major manufacturers o f equipment f o r mechanical p u l p i n g has developed a new s l o g a n : THINK YELLOW! I t i s g e n e r a l l y agreed t h a t most o f the dark c o l o r i n the mechanical pulp o r i g i n a t e s from the l i g n i n (19,20) - the aromatic polymer a c t i n g as a s t i f f matrix around and i n the c e l l u l o s e f i bers i n the wood. I t has been known f o r a long time t h a t the dark c o l o r can be p a r t i a l l y removed without removal o f the l i g n i n by b l e a c h i n g with a v a r i e t y o f chemicals (21). The most common of these i s hydrogen peroxide. Through wo"rR w i t h l i g n i n model compounds, i t has been shown t h a t hydrogen peroxide i s capable o f breaking down l i g n i n monomer u n i t s c o n t a i n i n g f r e e p h e n o l i c groups ( F i g u r e s 8, 9 ) . That such groups are a l s o r e s p o n s i b l e f o r most o f the dark c o l o r has been shown by spectrograph!c s t u d i e s on l i g n i n model compounds ( F i g u r e 10) and l i g n i n i t s e l f ( F i g u r e 11). E s p e c i a l l y i n t e r e s t i n p r a c t i c a l l y c o l o r l e s s , an , y c a t i o n ( F i g u r e 12). These r e s u l t s show t h a t i t i s today p o s s i b l e to b l e a c h l i g n i n to any b r i g h t n e s s without removing i t , but the expense would be t o t a l l y unacceptable. The c h a l l e n g e now i s t o develop a commercially f e a s i b l e process t h a t can accomplish a l l or almost a l l o f t h i s c o l o r r e d u c t i o n . Strength Another, e q u a l l y s e r i o u s d e f i c i e n c y o f mechanical pulp i s i t s mechanical weakness. Since such pulps are made by mechanical f i b e r s e p a r a t i o n , one o f the major d i f f i c u l t i e s i s to achieve such s e p a r a t i o n without unacceptable damage to the f i b e r w a l l , which would l e a d t o low s t r e n g t h . Modern technology has come a long way i n t h i s r e s p e c t , from the o r i g i n a l stone groundwood made on a g r i n d s t o n e as f a r back as 1844, t o today's d i s c r e f i n e r s which produce f i b e r s by rubbing c h i p s between metal d i s c s . One e s p e c i a l l y i n t r i g u i n g development i s the high-temperature, h i g h pressure process I mentioned b e f o r e , namely, the thermomechanical process. As I s a i d , TMP f i b e r s are separated r e l a t i v e l y i n t a c t . T h i s shows up i n the s u p e r i o r s t r e n g t h of TMP (16) compared to conventional groundwood (Table IX). Table IX Strength Values f o r Stone Groundwood, TMP, and K r a f t Pulp (Norway Spruce) Stone Groundwood TMP Kraft CS Freeness, ml 100 90 300 Burst F a c t o r 14 21 122 Breaking Length, m 3200 2500 11,380 Tear F a c t o r 35 63 107

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

256

CH

CH

3

r^Ol

H 0 , OH

[ U l

(-CH3OH)

2

CH 0'^ ^0CH 3

r

:

2

.

CHp^^O

3

ÔH

+

Ο v

3

H 0 , OH' 2

CH 0^ ^0CH OH 3

CH CHO-^CH COOH

2

3

Figure 9. Sequence for the reaction of hardwood lig­ nin models with alkaline hydrogen peroxide

COOCH, •"COOH

WAVELENGTH, nm

Figure

10.

Visible absorption spectra of solutions treated with varying amounts of hydrogen

of 4-methylsyringol peroxide

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

3

15.

LEOPOLD

257

Pulp Mill of the Future

Figure varying

11. peroxide-to-methoxyl ratios for wood lignin (4-hr reaction time)

milled-

4.0L-

3.0H

Ό

60

120 180 REACTION TIME, MIN.

240

Figure 12. Color (absorptivity) change on treat­ ment of original and modified lignins with H0 (H 0 /OCH = l) 2

2

2

2

3

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

258

N e v e r t h e l e s s , the s t r e n g t h o f TMP i s s t i l l f a r i n f e r i o r to that o f k r a f t . The reason i s t h a t the TMP f i b e r s do not bond to one another n e a r l y as w e l l as chemical f i b e r s ( F i g u r e s 13 and 14), and t h i s , i n t u r n , i s a s c r i b e d t o the presence i n the f i b e r of p r a c t i c a l l y a l l o f the l i g n i n i n the wood. So, again l i g n i n i s the c u l p r i t . I t tends to make the f i b e r s t i f f and unable to make f i r m c o n t a c t with other f i b e r s and thus prevent the format i o n o f hydrogen bonds, the primary f o r c e h o l d i n g f i b e r s t o g e t h e r (22,23). Bonding Agents W e l l , can anything be done about t h i s problem? There are two p o s s i b l e b a s i c approaches the papermaking p r o c e s s f i b e r s t o g e t h e r and thus i n c r e a s e the s t r e n g t h . S i n c e t h i s type of f i b e r tends t o be s t i f f , t h i s approach would be o f s p e c i a l i n t e r e s t i n r i g i d p r o d u c t s , such as paperboard. There a r e , o f course, a wide v a r i e t y o f polymeric products t h a t c o u l d be used as r e i n f o r c i n g agents or "adhesives." Unfort u n a t e l y very few, i f any, products t e s t e d t o date have shown s u f f i c i e n t promise t o be used commercially. The main reason f o r t h i s i s undoubtedly t h a t e x i s t i n g products do not provide s u f f i c i e n t bonding a t an economical add-on l e v e l . T h i s i s a t l e a s t p a r t i a l l y a r e s u l t o f our i n a b i l i t y t o s e l e c t i v e l y i n t r o d u c e the a d d i t i v e s i n t o those l o c a t i o n s where they would be e f f e c t i v e , v i z . , on the s u r f a c e o f the f i b e r and e s p e c i a l l y where the f i bers c r o s s one another. The q u e s t i o n of how polymers adsorb onto f i b e r s u r f a c e s and how they i n t e r a c t with one another i s of g r e a t importance t o t o day's papermaker because s y n t h e t i c polymers, e s p e c i a l l y p o l y e l e c t r o l y t e s , are f i n d i n g i n c r e a s i n g use as s o - c a l l e d r e t e n t i o n a d d i t i v e s . These are a d d i t i v e s which enhance r e t e n t i o n , i n the f i b e r mat, of f i n e p a r t i c l e s , such as pigments and f i b e r f r a g ments. Retention improvement i s o f obvious importance, both f o r decreasing c o s t s and reducing e f f l u e n t problems (24-26). In the course of r e t e n t i o n s t u d i e s , i t has been found t h a t p a r t i c u l a r l y outstanding r e s u l t s can be obtained by u s i n g a two-step, twocomponent system o f a d d i t i v e s o f o p p o s i t e e l e c t r i c charge. Some t y p i c a l r e s u l t s are shown i n F i g u r e 15. The most l i k e l y explanat i o n f o r t h i s phenomenon can be d e r i v e d from the s o - c a l l e d "patch" theory (27). I t i s assumed t h a t when the c a t i o n i c polymer i s added t o the n e g a t i v e l y charged c e l l u l o s e , the former i s adsorbed in p o s i t i v e l y charged patches. These l a t t e r w i l l then a t t a c h t o n e g a t i v e l y charged patches on other f i b e r s ( F i g u r e 16). J u s t how the a d d i t i o n o f n e g a t i v e l y charged polymer r e i n f o r c e s or promotes t h i s mechanism i s not q u i t e c l e a r . One p o s s i b i l i t y i s t h a t these polymers, u s u a l l y of g r e a t m o l e c u l a r weight, a c t as a c t u a l p h y s i cal " b r i d g e s " between f i b e r s or p a r t i c l e s .

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

LEOPOLD

Pulp

Figure

Mill

14.

of the

Future

TMP fibers after bond rupture tron micrograph)

(scanning

elec-

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

N a S 0 - 3 0 0 p p m , pH 6.0 2

4

A L U M - 5 0 p p m , N a S 0 - 3 0 0 ppm, pH 6.0 2

4

CATIONIC P O L Y M E R - 8 ppm

CATI01MIC P O L Y M E R - 4 p p m ,

J

L

10

20

Figure 15.

J

3

ANIONIC P O L Y M E R - 8 ppm

L

Retention of Ti0

Figure 16.

J

2

in a dynamic papermaking

Schematic

of charge patch

I

system

model

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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Now, r e t u r n i n g to the problem of adding polymeric r e i n f o r c ing agents to the f i b e r , i t appears t h a t the above mechanism might be of i n t e r e s t . I f a s u i t a b l e c a t i o n i c polymer were added and adsorbed, i n very low c o n c e n t r a t i o n , i t would tend to remain on the f i b e r s u r f a c e . Then, i f a long-chain a n i o n i c polymer were added, which would form an i n s o l u b l e s a l t with the c a t i o n i c ( a p o l y s a l t ) , t h i s would, o f course, be l o c a t e d on the s u r f a c e and would tend to concentrate a t the f i b e r c r o s s i n g s by v i r t u e o f the s u r f a c e t e n s i o n of the s o l u t i o n . C l e a r l y , research along these l i n e s could turn out to be well worth the e f f o r t . Chemical M o d i f i c a t i o n The other approach t bond strengthenin i based chemi c a l m o d i f i c a t i o n of th pens t h a t c e r t a i n chemica treatments modify the l i g n i suc a way t h a t the s t r e n g t h of the mechanical pulp i n c r e a s e s manyf o l d (Table X), presumably because of improved bonding ( F i g u r e 17). U n f o r t u n a t e l y , these e m p i r i c a l r e s u l t s have been obtained at e n t i r e l y uneconomical chemical consumption l e v e l s . In my o p i n i o n , our only hope to f i n d a p r a c t i c a l m o d i f i c a t i o n process r e s t s on developing a thorough understanding of the mechanism involved. The reason f o r the poor bonding o f l i g n i n - r i c h f i b e r s may be two-fold: 1) lack o f f i b e r - t o - f i b e r contact as a r e s u l t o f f i b e r s t i f f n e s s and poor c o n f o r m a b i l i t y , and 2) l i g n i n c o n t a i n s fewer hydrogen bonding s i t e s than c e l l u l o s e , and thus i t s presence reduces the o p p o r t u n i t y f o r bonding. I do not b e l i e v e t h a t the second f a c t o r i s important because the system, even with the presence of 25-30% l i g n i n , i s exceedingly r i c h i n hydroxyl groups, the p r i n c i p a l hydrogen bonding s i t e . One s e t of e x p e r i ments t h a t we have performed tends t o support t h i s view: We i n troduced a number of carboxyl groups i n t o the l i g n i n and found an increase i n s t r e n g t h . A t f i r s t glance, t h i s seems to show t h a t t h i s i s the r e s u l t o f i n t r o d u c i n g a new and more powerful bonding s i t e . However, when a hydroxyethyl group was introduced i n t o the l i g n i n , the same strength i n c r e a s e was observed. I t i s u n l i k e l y t h a t i n t r o d u c t i o n of a few a d d i t i o n a l primary hydroxyl groups i n t o the system should have such a profound e f f e c t . I t i s much more l i k e l y t h a t a l l these s u b s t i t u t i o n s and chemical m o d i f i c a t i o n s help break up the r i g i d l i g n i n s t r u c t u r e , thus making i t more f l e x i b l e , e s p e c i a l l y i n the presence of water. T h i s i s f u r t h e r supported by the f a c t t h a t pure s u b s t i t u t i o n tended to have a l i m i t e d e f f e c t , whereas o x i d a t i v e treatment showed a more d r a s t i c s t r e n g t h i n c r e a s e . T h i s i n d i c a t e s t h a t the most important e f f e c t of the o x i d a t i o n i s a p a r t i a l depolymerization o f the l i g n i n , a l l o w i n g g r e a t e r f l e x i b i l i t y of the polymer network. I t appears, then, t h a t we now know what to look f o r . The i d e a l chemical treatment o f the f i b e r would be one t h a t would p a r t i a l l y depolymerize the l i g n i n while a t the same time breaking down a l l aromatic u n i t s c o n t a i n i n g f r e e p h e n o l i c hydroxyl groups. In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY S-

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15.

LEOPOLD

Pulp

Mill

of the

Future

Figure 17. Scanning electron TMP handsheet: (a) untreated;

263

micrograph (255 X) (b) treated with 3%

of O

s

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

264

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

T h i s would l e a d t o a well-bonded pulp with a s t a b l e and reasonably high b r i g h t n e s s . Since many o x i d a t i v e treatments can a l s o be used f o r b l e a c h i n g , t h i s i s not pure s p e c u l a t i o n , as shown by the r e s u l t s i n T a b l e XI. A p p l i c a t i o n i n the M i l l Assuming t h a t such a treatment were found, how would i t be a p p l i e d ? In the i n t e r e s t o f s i m p l i c i t y and low c a p i t a l c o s t , the i d e a l p l a c e to do i t would be r i g h t i n the r e f i n e r . The thermomechanical r e f i n e r i s e s p e c i a l l y s u i t e d f o r t h i s s i n c e i t operates a t e l e v a t e d temperature and p r e s s u r e . We might climax t h i s l i t t l e t o u r i n t o the l a n d o f U t o p i a by v i s u a l i z i n g the u l t i m a t pul m i l l I t would c o n s i s t f ber of r e f i n e r s , groupe them p r e s s u r i z e d , each equipped f o r a s p e c i f i c chemical t r e a t ment or polymer a d d i t i o n . The r e f i n e r system would be immedia t e l y f o l l o w e d by the paper machine, v i a a simple c e n t r i f u g a l c l e a n i n g system and the a p p r o p r i a t e storage c a p a c i t y to provide s u f f i c i e n t f l e x i b i l i t y . Such a pulp m i l l appears t o be reduced to i t s u l t i m a t e e s s e n t i a l components, and i t i s d i f f i c u l t to conc e i v e o f a d d i t i o n a l s i m p l i f i c a t i o n , except, o f course, i n the des i g n o f the paper machine. But t h a t i s another s t o r y , as Hans C h r i s t i a n Andersen would have s a i d . L i k e a l l d e s c r i p t i o n s of U t o p i a , t h i s i s an o v e r s i m p l i f i e d s t o r y t h a t g l o s s e s over d i f f i c u l t i e s , downplays problems, and says n o t h i n g about the "nuts and b o l t s " aspects o f a pulp m i l l . N e v e r t h e l e s s , I t h i n k t h a t there i s now s u f f i c i e n t i n f o r m a t i o n a v a i l a b l e t o show t h a t r a d i c a l l y new p u l p i n g schemes are fundam e n t a l l y f e a s i b l e . Furthermore, success i n any or a l l o f the areas I have sketched here would be o f such immense v a l u e , e c o n o m i c a l l y and otherwise, t h a t we would be unwise and even n e g l i g e n t i f we d i d not make a major e f f o r t to provide the needed new knowledge and new technology. I t may not be an exaggeration to say t h a t the f u t u r e growth and p r o s p e r i t y o f the i n d u s t r y depends on i t ! SUMMARY 1. The pulp and paper i n d u s t r y w i l l undergo very important changes d u r i n g the next few decades, prompted by shortages o f water, energy, c h e m i c a l s , f i b e r , and c a p i t a l , as w e l l as by environmental c o n s t r a i n t s . 2. Some p o s s i b l e f u t u r e developments are d i s c u s s e d i n the l i g h t of recent research, especially i n oxygen-alkali pulping and the expanded use o f mechanical wood p u l p , two areas cons i d e r e d as e s p e c i a l l y promising. The former approach would a l l e v i a t e many environmental problems, w h i l e the l a t t e r would g r e a t l y expand the a v a i l a b l e raw m a t e r i a l supply.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

67

56

Brightness, % Elrepho

50

55 52 46

41

32

Tear F a c t o r

64

4700 4500

1940

1695

890

Breaking Length, m

51

24.6 22.7

c

6.6

Density, g/cm 6.1

2

3.4

2

Burst Factor

2

0.43

2

0.34

2

0.29

2

0.28

2

Peracetic a c i d 5.1 H 0 2.1

Peracetic a c i d 16.7 H 0 2.3

Peracetic a c i d 3.9 H 0 0.6

Peracetic a c i d 8.8 H 0 1.8 2

Stage I I pH 7.5

Stage II pH 7.5

0.23

% Residual Chemical

Control

Stage I 40% Peracetic Acid pH 3.5

Stage I 20% Peracetic Acid pH 3.5

Table X I . Two-Stage Treatment o f Spruce Groundwood (35 Mesh) with P e r a c e t i c A c i d

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3. Starting out from the current concept of a multistage oxygen pulping process, a number of possible simplifications are described. One would involve pulping pre-fiberized wood, the other pulping of chips in one stage under very vigorous agitati on. 4. A scheme of pulping wood with oxygen-alkali followed by bleaching with ozone has shown great promise. 5. Schemes for improving the strength of mechanical pulps are discussed. One approach involves the use of polymeric additives, the other an oxidative chemical modification of the fiber. The latter might also be combined with an improvement in pulp color (bleaching). 6. The ultimate pulp mill is sketched. It consists solely of sets of mechanical refiners all equipped fo variou chemical treatments. LITERATURE CITED 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

11.

Libby, C . E . , "Pulp and Paper Science and Technology," Vol. I, pp. 10-13, McGraw-Hill Book Co., New York, 1962. Hannigan, J., Tappi (1976) 59 (1) p. 89. Young, H.E., Pulp and Paper (1974) 48 (15) p. 46. Powell, L . N . , Shoemaker, J.D., Lazar, R., and Barker, R.G., Tappi (1975) 58 (7) p. 150. Auchter, R.J., "Whole-Tree Utilization - Fact or Fantasy," TAPPI Alkaline Pulping Conference, Williamsburg, VA, October 27-29, 1975. Rapson, W.H. and Reeve, D.W., Tappi (1973) 56 (9) p. 112. Anonymous, Tappi (1976) 59 (2) p. 26. Cox, L.A. and Worster, H.E., Tappi (1971) 54 (11) p. 1890. Palenius, T. and Hiisvirta, L., Pulp and Paper Mag. Can. (1970) 72 (21) p. 63. Makkonen, H.P., Sarkanen, K.V., Johanson, L . N . , Gratzl, J.S. and Ernst, C., "Preliminary Studies of Peroxide and Oxygen Pretreatment in Alkaline Pulping," TAPPI Alkaline Pulping Conference, Houston, Texas, October 25-28, 1971. Carles, J.E., Choudens, C. de, and Monzie, P., Rev. A.T.I.P. (1973) 27 (2) p. 139.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

15.

LEOPOLD

Pulp Mill of the Future

12. Marton, R. and Leopold, B., Appita (1973) 27 (2) p. 112. 13. Chang, H.-M., McKean, W.T., Gratzl, J.S., and Lin, C.K., Tappi (1973) 56 (9) p. 116. 14. Minor, J.L. and Sanyer, N., Tappi (1974) 57 (5) p. 120. 15. Lindström, L.-Å. and Samuelson, O., Tappi (1975) 58 (7) p. 146. 16. Mannström, B., Paperi ja Puu (1974) 56 (5) p. 158. 17. Secrist, R.B. and Singh, R.P., Tappi (1971) 54 (4) p. 581. 18. Underhay, G.F., Tapp 19. Van den Akker, J.Α., Lewis, H.F., Jones, G.W., and Buchanan, M.A., Pulp and Paper Mag. Can. (1949) 50, p. 87. 20. Jones, G.W., Tappi (1950) 33 (3) p. 149. 21. Singh, R.P., Tappi (1966) 49 (7) p. 281. 22. Nissan, A.H. and Sternstein, S.S., Tappi (1964) 47 (1) p. 1. 23. Byrd, V.L., Tappi (1974) 57 (6) p. 87. 24. Britt, K.W., Tappi (1973) 56 (10) p. 46. 25. McKague, J., Etter, D.O., Pilgrim, J.O., and Griggs, W.H., Tappi (1974) 57 (12) p. 101. 26. Frankle, W.E. and Sheridan, J.L., Tappi (1976) 59 (2) p. 84. 27. Gregory, J., J. Coll. and Inter. Sci. (1973) 42, p. 448. 28. Soteland, N. and Kringstad, Κ., Norsk Skogind. (1968) 22, p. 46. 29. Bachorik, T . J . , M.S. Dissertation (1969) SUNY College of Environmental Science and Forestry, Syracuse, New York. 30. Liebergott, N., Pulp and Paper Mag. Can. (1972) 73, p. T214. 31. Becher, J.J., Hoffman, G.R., and Swanson, J.W., Tappi (1976) 59 (1) p. 104. Contribution No. 104 from the Empire State Paper Research Insti­ tute, SUNY College of Environmental Science and Forestry, Syra­ cuse, New York 13210. In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

267

16 Responsible Husbandry ROBERT W. SINGLETON Man-Made Fibers Producers Assoc., 1150 17th St., N.W., Washington, D.C. 20036

I wish to express my thanks to the program com mittee for inviting most interesting symposium. This afternoon and tomor row you w i l l hear very specific examples of a general topic which I now have the privilege to introduce. A l l of our speakers collectively w i l l attempt to communicate to you the basic message that the man-made fiber producers of this country as well as all related activities in the conversion of fibers to finished consumer products run a "tight ship" in terms of e f f i ciency, fuel conservation, and minimal adverse impact on our earth's environment -- that our industry in fact practices good husbandry. Many dire predictions have been heard concerning the impact of the energy shortage on the availability and price of man-made fibers. Part of this is due to the fact that o i l and natural gas play a two-fold role in our industry. These energy sources are intrinsic raw materials as well as sources of energy to operate the fiber forming process. However, our industry has been known from its i n ception for i t s efficiency and boasts of its 95% conversion efficiency of chemical intermediates to f i n ished fiber. In order to place the man-made fiber i n dustry's use of petroleum into perspective, i t should be pointed out that raw materials plus the energy to convert these into finished fibers utilizes only 1% of the nation's entire petroleum demand. This fact along with legislation ensuring priority allocation to our industry, makes long term shortages of man-made fibers unlikely. 271

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

In s p i t e o f t h i s our i n d u s t r y has v o l u n t a r i l y s u b s c r i b e d t o a 15% r e d u c t i o n i n energy consumption f o r t h e p e r i o d o f 1972 t o 1 9 8 0 · L e t ' s s e e how we a r e doing* The T e x t i l e Economics Bureau. I n c . has j u s t completed e s t i m a t i n g t h e energy t o convert i n t e r m e d i ­ a t e s t o f i b e r s on a p e r pound o f p r o d u c t i o n b a s i s f o r t h e y e a r s 1 9 7 1 , 1 9 7 3 , a n d 1974 f o r a l l o f t h e f i b e r s made b y o u r i n d u s t r y . Table I l i s t s these f i g u r e s . U s i n g t h e s e numbers i t i s e v i d e n t t h a t t h e g o a l o f energy c o n s e r v a t i o n has a l r e a d y been reached w e l l ahead o f schedule. TABLE I Energy Consumptio (BTU p e r p o u n ) Year BTU/lb. F i b e r % Conservation' 1971 35.2 1973 25.9 26 1974 28.0 20 ( ) u s i n g 1971 a s a b a s e . The l o w e r l e v e l o f c o n s e r v a t i o n i n 1974 c o m p a r e d w i t h 1973 r e f l e c t s a r e d u c t i o n i n p r o d u c t i o n w i t h o u r mem­ ber companies o p e r a t i n g s i g n i f i c a n t l y b e l o w optimum production capacity, whenever t h i s o c c u r s , i t i s e x ­ pected that energy consumption w i l l be l e s s than o p t i ­ mum i n e f f i c i e n c y . The n e x t s u b j e c t t o be c o n s i d e r e d i n t h e attempt to further increase process e f f i c i e n c y i s that o f bet­ ter u t i l i z a t i o n o f by-products. Let me g i v e y o u s e v e r ­ a l e x a m p l e s o f how member c o m p a n i e s a r e e x t r a c t i n g u s e f u l products from t h e i r waste streams. One l a r g e f i b e r producer has been s h i p p i n g by-products o f i t s a d i p i c a c i d p l a n t t o a c h e m i c a l company i n H o u s t o n . T h i s company r e p r o c e s s e s t h e s e b y - p r o d u c t s into f i v e t y p e s o f d i b a s i c e s t e r s (DBE) t o b e s o l d a s raw mate­ r i a l s f o r other processes. C a r b o n d i o x i d e , a l e f t o v e r f r o m ammonia m a n u f a c ­ t u r e , i s b e i n g made i n t o l i q u i d C 0 and used i n t h e manufacture o f methanol o r as an a i d i n o i l r e c o v e r y . C0 i s i n j e c t e d i n t o o l d o i l w e l l s t o h e l p b r i n g more o i l to the surface. These examples o f c o n s e r v a t i o n suggest a s i g n i f i ­ cant l e v e l o f chemical intermediate supply from prod­ u c t s n o r m a l l y d i s c a r d e d when c o n s e r v a t i o n was n o t s u c h a prime c o n s i d e r a t i o n . 1

2

2

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

16.

SINGLETON

Responsible Husbandry

273

Good h u s b a n d r y i s n o t o n l y optimum c o n s e r v a t i o n . I t must i n c l u d e m a i n t a i n i n g a c l e a n h o u s e . Our i n d u s t r y has an o b l i g a t i o n t o maintain c l e a n water and a i r i n d i s t r i c t s o f o u r c o u n t r y w h e r e we p r a c t i c e o u r e f f i c i e n t manufacturing. T h e F e d e r a l W a t e r P o l l u t i o n C o n t r o l A c t Amendmenis o f 1972 r e q u i r e t h e i n s t a l l a t i o n o f " b e s t p r a c t i c a l t r e a t m e n t " b y 1977 a n d " b e s t a v a i l a b l e t r e a t m e n t " b y 1983. A majority o f t h echemical industry, including f i b e r p r o d u c e r s , i s o n s c h e d u l e t o meet t h i s r e q u i r e ment. Industry has i n s t a l l e d waste water treatments u s i n g t h e b e s t p r a c t i c a l t r e a t m e n t a n d i n some c a s e s even h a s gone beyon ulations. In fact e n t w a t e r t o t h e T e n n e s s e e R i v e r much c l e a n e r t h a n t h a t which they take o u t . The c a p i t a l c o s t s f o r w a t e r p u r i f i c a t i o n a r e s t a g g e r i n g a n d , t h e r e f o r e , we a r e r e q u e s t i n g t h a t t h e F e d e r a l G o v e r n m e n t r e c o n s i d e r t h e 1983 g o a l b y f i r s t s t u d y i n g t h e o v e r a l l i m p a c t o f t h e 1977 g o a l i n t e r m s o f w a t e r q u a l i t y b e f o r e i t m a n d a t e s t h e 1983 r e q u i r e ment. T h e i n v e s t m e n t r e q u i r e d t o make t h i s marginal c h a n g e f r o m t h e 1977 r e q u i r e m e n t t o t h e 1 9 8 3 s t a t u t e w i l l be d i s p r o p o r t i o n a l l y high and should not ber e quired unless absolutely necessary. L e t me d i g r e s s h e r e t o s u g g e s t t h a t i t i s n o t w i s h f u l t h i n k i n g t o assume t h e F e d e r a l Government w i l l be r e c e p t i v e t o a l e s s e n i n g o f w a t e r p o l l u t i o n r e s t r i c t i o n s a r e overburdensome i n terms o f c o s t w i t h no added a s s u r a n c e o f p u b l i c p r o t e c t i o n . R e c e n t l y t h e Counc i l o n Wage a n d P r i c e S t a b i l i t y (CWPS) c a u t i o n e d regulatory agencies t o r e s i s t i s s u i n g proposed r u l e s that would p o t e n t i a l l y p r o h i b i t even a m i n i m a l , n o n - i n j u r i o u s presence o f a given substance b e l i e v e d t o be a health hazard a t a high l e v e l o f concentration. CWPS p o i n t s out that t h e a d d i t i o n a l cost t o insure zero conc e n t r a t i o n o f a substance r a t h e r than a non-hazardous l e v e l c a n b e e x t e n s i v e w i t h no b e n e f i t w h a t s o e v e r t o the consumer. In t h i s p a r t i c u l a r case i np o i n t , i n dustry had responded t o t h e problem and t h e i r process changes reduced t h e l e v e l o f contaminant t o a s a f e level. T h i s o p i n i o n o f CWPS t a k e n a s a g e n e r a l precede n t g i v e s man-made f i b e r p r o d u c e r s c o n f i d e n c e t h a t a more r e a l i s t i c y a r d s t i c k c a n a n d w i l l b e a p p l i e d b y t h e

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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Government i n a l l a r e a s o f r e g u l a t i o n . Next l e t us c o n s i d e r a i r borne p o l l u t a n t s . Again i n d u s t r y has been r e s p o n s i v e t o t h e F e d e r a l r e q u i r e ments and e x p e c t s t o meet a l l l o c a l and n a t u r a l g o a l s . Let us c o n s i d e r t h e l e v e l o f e f f o r t r e q u i r e d f o r b o t h a i r and water p o l l u t a n t c o n t r o l . I n 1974, o n e o f o u r member c o m p a n i e s s p e n t $ 1 2 0 m i l l i o n t o o p e r a t e a n d m a i n t a i n p o l l u t i o n abatement f a c i l i t i e s and conduct e n v i r o n m e n t a l r e s e a r c h and development programs. By t h e e n d o f 1975, t h i s company w i l l h a v e c o m m i t t e d t o e x p e n d i n g a t o t a l o f $550 m i l l i o n f o r p o l l u t i o n c o n t r o l e q u i p m e n t i n t h e U. S. f a c i l i t i e s a l o n e . Granted this i s for their entir only a p o r t i o n , bu t h e number o f f i b e r p r o d u c e r s i n t h e U. S., I w o u l d e s t i m a t e a t o t a l e x p e n d i t u r e o f c l o s e t o $1 b i l l i o n s p e n t t o d a t e i n p o l l u t i o n a b a t e m e n t b y t h e man-made f i b e r p r o d u c e r s s i n c e the enactment o f e n v i r o n m e n t a l control legislation. Now, we f e e l t h a t i t i s o n l y f a i r t o i n f o r m t h e c o n s u m e r t h a t t h e y must s h a r e i n t h i s expense i n terms o f h i g h e r r e t a i l c o s t s . These are i n e v i t a b l e to maintain a s a t i s f a c t o r y p r o f i t margin. When we c o n s i d e r a i r p o l l u t a n t s , we m u s t c o n s i d e r the t o x i c o l o g i c a l e f f e c t s of these m a t e r i a l s both to t h e c i t i z e n s i n t h e s u r r o u n d i n g community and, perhaps e v e n m o r e c r i t i c a l l y , t o t h o s e who come i n t o d i r e c t c o n t a c t w i t h c h e m i c a l s i n our p l a n t s . So l i t t l e i s known a b o u t t h e a d v e r s e e f f e c t s o f c h e m i c a l s t h r o u g h long term exposure. The w h o l e s u b j e c t i s r e c e i v i n g i n t e n s e a t t e n t i o n by Government r e g u l a t o r y a g e n c i e s and b y o u r own member c o m p a n i e s . Even b e f o r e t h e i n t e n s e G o v e r n m e n t i n t e r e s t was e x p r e s s e d , o u r member comp a n i e s e s t a b l i s h e d programs t o i n v e s t i g a t e the e f f e c t s o f c o m m o n l y u s e d c h e m i c a l s on o u r e m p l o y e e s ' h e a l t h . M o r e r e c e n t l y , s e v e r a l o f o u r members, w o r k i n g through t h e i r p a r e n t o r g a n i z a t i o n s , have banded t o g e t h e r t o support the Chemical Industry I n s t i t u t e of Toxicology (CUT) . T h i s o r g a n i z a t i o n , funded by t h e c h e m i c a l i n d u s try, grants contracts to laboratories to perform r e search i n t o the s a f e t y o f exposure t o c h e m i c a l s . H o p e f u l l y , as t h e I n s t i t u t e grows i t w i l l d e v e l o p i t s facilities. Among t h e I n s t i t u t e ' s g o a l s a r e :

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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275

1· P r o v i d e a sound, f o r c e f u l , s c i e n t i f i c indust r y p r e s e n c e i n t h e complex a r e a o f c h e m i c a l s a f e t y evaluation* 2. G e n e r a t e and i n t e r p r e t d a t a on c h e m i c a l s from the viewpoints o f t o x i c o l o g y , epidemiology, b i o l o g y , and o t h e r r e l e v a n t f i e l d s . 3. D e v e l o p new t e s t m e t h o d s b e a r i n g r e l a t i o n t o t h e p o t e n t i a l l y d e l e t e r i o u s e f f e c t s o f c h e m i c a l s on human h e a l t h . 4. D i s s e m i n a t e i n f o r m a t i o n on p o t e n t i a l h a z a r d s of c h e m i c a l s and encourage u s e o f such knowledge t o m i n i m i z e human r i s k s . 5. Promote t h training of toxicologists scientists i n related fields. To d a t e , 18 c o m p a n i e s h a v e j o i n e d i n s u p p o r t o f the Chemical Industry I n s t i t u t e o f Toxicology committ i n g a t o t a l b u d g e t o f $14 m i l l i o n t o b e d i s p e r s e d i n research grants. The I n s t i t u t e opened i t s o f f i c e s i n the Research T r i a n g l e Park i n R a l e i g h , North C a r o l i n a , t h i s F e b r u a r y (1976) and h a s begun i t s s t u d y o f t h e p o s s i b l e t o x i c o l o g y e f f e c t s o f s e v e r a l commodity chemicals. I n summary t h e n : T h e man-made f i b e r i n d u s t r y h a s improved upon i t s h i g h l e v e l o f e f f i c i e n c y i n terms o f e n e r g y c o n s e r v a t i o n a n d maximum u t i l i z a t i o n o f b y - p r o d ucts. I n a d d i t i o n , we h a v e b e e n r e s p o n s i v e t o t h e need of p r e s e r v i n g c l e a n a i r , water and the h e a l t h o f our workers. W h i l e we s u p p o r t many o f t h e v o l u n t a r y a n d G o v e r n m e n t m a n d a t e d t a r g e t s , we a s k f o r a c o n t i n u e d assessment o f these t a r g e t s t o i n s u r e a p p r o p r i a t e environmental protection at acceptable cost. While i t i s t e c h n o l o g i c a l l y f e a s i b l e t o meet t h e p r e s e n t targets, the c a p i t a l expenditure w i l l be s u b s t a n t i a l . T h i s c o s t must b e p a s s e d o n t o t h e c o n s u m e r r e s u l t i n g in significant price increases. T h e r e i s some i n d i c a t i o n t h a t t h e F e d e r a l Government i n t h e f o r m o f t h e C o u n c i l o n Wage a n d P r i c e S t a b i l i t y i s r e s p o n s i v e t o t h i s p o i n t a n d we l o o k f o r w a r d t o a c o o p e r a t i v e effort t o a t t a i n a n o p t i m u m l e v e l o f h u s b a n d r y , i . e . , optimum e f f e c t i v e n e s s a t an acceptable cost.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

17 Energy Conservation in Caprolactam Recovery G. KIOPEKLY Central Engineering, American Enka Co., Enka, NC 28728

The increase in the cost of energy in recent years has made it necessary to conside energy at relatively lo plant operations, significant quantities of process heat energy are removed and rejected, in water-cooled heat exchangers, either to once-through river water or to water in circulating cooling tower systems. In the manufacture of nylon-6 fibers, caprolactam is polymerized to form the basic polymer which is eventually spun into fibers. Because of the usual kinetic and equilibrium relationships, the polymer from the polymerization process contains unreacted monomer and some higher molecular weight oligomers which must be essentially removed before the polymer is spun into a fiber. One method of effecting the removal of unreacted monomer and oligomers is by extraction with hot water. The extract is fairly dilute containing 5 - 10 wt. % organics. For obvious economic reasons and for pollution control considerations, the organics are recovered for recycle to the polymerization process. Since caprolactam is relatively non-volatile, with a normal boiling point of 270°C, separation from water is fairly easy. However, the quantity of energy required is substantial when the separation is accomplished by the evaporation of water. In addition, water contaminated with caprolactam at various low concentrations from the plant areas is collected for recovery and for pollution abatement. In 1972, the American Enka Company initiated a program to reduce the cost of caprolactam recovery. At that time, the price of purchased caprolactam was relatively low, ca. $0.20/lb., and although the economics of recovery were not particularly attractive, pollution considerations mandated operation of a recovery system. More recently the price of caprolactam has increased to $0.35 - $0.40/lb., providing an additional economic incentive for more efficient recovery. Since cooling towers were already in use at American Enka Plants, the possibility of using their evaporative capacity in the recovery operation was explored. 276

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

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I n i t i a l t e s t s were made w i t h an e x i s t i n g t h r e e - c e l l c o o l i n g t o w e r . A s c h e m a t i c f l o w d i a g r a m o f t h i s s y s t e m i s shown i n F i g u r e 1. The c o o l i n g t o w e r was o f s t a n d a r d c o n s t r u c t i o n w i t h redwood f i l l , t r a n s i t e s h e a t h i n g , g a l v a n i z e d s t e e l f i t t i n g s and induced d r a f t . The f e e d t o t h e s y s t e m shown c o n s i s t e d o f c o n t a m i n a t e d w a t e r f r o m a number o f s o u r c e s , e.g., pump l e a k s , e q u i p ment o r l i n e c l e a n o u t s and c o n d e n s a t e f r o m t h e s p i n n i n g and o t h e r plant areas. For a y e a r - r o u n d a v e r a g e o f 20°F t e m p e r a t u r e d i f f e r e n t i a l a c r o s s t h e c o o l i n g tower and a t o t a l w a t e r c i r c u l a t i n g r a t e o f 2,700 g a l l o n s p e r m i n u t e t o t h e t h r e e - c e l l t o w e r , a w a t e r e v a p o r a t i o n r a t e o f 26,000 l b s . / h r . was r e a l i z e d . The v a l u e o f t h i s e v a p o r a t i o n , i n t e r m s o f d i r e c t steam r e q u i r e d t o a c c o m p l i s h t h e same e v a p o r a t i o n , i s a b o u $500,000/yr $4.50 $5.00 p e r t o n o f steam The i n i t i a l t e s t s were n o t w i t h o u t p r o b l e m s . As m i g h t be a n t i c i p a t e d , t h e d r i f t ( e n t r a i n m e n t ) from t h e c o o l i n g tower r e s u l t e d i n t h e l o s s o f o r g a n i c m a t e r i a l s w h i c h was e n v i r o n m e n t a l l y unacceptable as a r o u t i n e o p e r a t i o n . The d r i f t was e s s e n t i a l l y e l i m i n a t e d by t h e i n s t a l l a t i o n o f a t w o - i n c h l a y e r o f Enkamat, a nonwoven mesh o f r e l a t i v e l y c o a r s e n y l o n - 6 f i l a m e n t s . A f t e r n i n e months i n o p e r a t i o n , t h e f a n g e a r box and s u p e r s t r u c t u r e above t h e Enkamat were c o m p l e t e l y c l e a n . C e l l s i n which Enkamat had n o t been i n s t a l l e d had c r u s t y d e p o s i t s on t h e f a n g e a r boxes a n d on t h e s u p e r s t r u c t u r e . The c o s t o f t h e Enkamat was 10 p e r c e n t o f a c o m p a r a b l e s t a i n l e s s s t e e l mesh. D u r i n g a p e r i o d o f o p e r a t i o n when t h e c o n c e n t r a t i o n o f c a p r o l a c t a m i n t h e c o o l i n g t o w e r w a t e r was f a i r l y l o w , c a . 2 w t . %, the g r o w t h a n d a c c u m u l a t i o n o f a l g a e p r o c e e d e d t o a s u f f i c i e n t d e g r e e t h a t t h e w o o d - f i l l i n one o f t h e c e l l s c o l l a p s e d f r o m t h e weight o f t h e a l g a e . Caprolactam a t c o n c e n t r a t i o n s o f 6 - 7 wt. % a c t s a s an a l g i c i d e o r a t l e a s t a s a s t r o n g i n h i b i t o r t o t h e growth o f a l g a e ; a t c o n c e n t r a t i o n s o f about 2 wt. % o r l o w e r , caprolactam i s apparently a nutrient f o r algae. The u s e o f c a p r o l a c t a m - c o n t a i n i n g w a t e r a s t h e c o o l i n g medium i n h e a t e x c h a n g e r s has n o t r e s u l t e d i n a n y s e r i o u s f o u l i n g problems. P e r i o d i c c l e a n o u t s o f a p p r o x i m a t e l y once a year a r e sufficient. Based on t h e e x p e r i e n c e w i t h t h e e x i s t i n g c o o l i n g t o w e r , a p r o j e c t f o r t h e i n s t a l l a t i o n o f s u c h a s y s t e m was a p p r o v e d . In the p r o p o s e d i n s t a l l a t i o n , t h e c o o l i n g t o w e r w i l l be c o n s t r u c t e d o f s t a i n l e s s s t e e l Type 304. F o r t h e same p e r f o r m a n c e r e q u i r e ments, t h e i n s t a l l e d c o s t o f a s t a i n l e s s s t e e l c o o l i n g tower i s e s s e n t i a l l y t h e same a s f o r t h e more c o n v e n t i o n a l w o o d - f i l l c o o l i n g tower. The r e a s o n s f o r t h i s c o s t e q u i v a l e n c e a r e : 1.

The s t a i n l e s s s t e e l t o w e r has an i n t e g r a l b a s i n ; woodf i l l c o o l i n g towers u s u a l l y r e q u i r e a s e p a r a t e c o n c r e t e basin.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

278

" (^j)

CQNDENSER

RECYCLE TO PROCESS

EVAPORATOR

COOLING TOWER DILUTE

CONCENTRATED

FEED

SOLUTION EVAPORATOR

FEED

TABLE I SUMMARY OF TEST δ PROPOSED COOLING TOWERS DATA DESIGN PERFORMANCE STAINLESS (1)

WOOD Water

F l o w p e r C e l l , gpm

Initial

Water T e m p e r a t u r e , °F

900

500 (975)

120

132

85

F i n a l Water T e m p e r a t u r e , °F Air

Wet B u l b T e m p e r a t u r e , °F

Air

Flow per C e l l , cfm

75 175,000

85 (56) 78 70,000

PHYSICAL DATA Number o f C e l 1 s ( p e r e e l 1), f t .

Width Length

(per c e l l ) , f t .

H e i g h t o f Fan Deck, f t . Fan M o t o r Horsepower Shipping Weight, l b s . (1)

per Cell

3

2

7 16 14

12

25 67,800

Numbers i n p a r e n t h e s e s a r e a l t e r n a t e speci f i c a t ions.

4.5 Grade

30 16,500

performance

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

17.

KioPEKLY

Energy

Conservation

in Caprolactam

Recovery

279

2.

The stainless steel tower is inherently fireproof; a woodf i l l tower requires a sprinkler system. 3. The stainless steel tower requires less plan area, less height and weighs about half of an equivalent wood-fill tower. Additional advantages of a stainless steel cooling tower are: 1. Resistance to corrosion and weathering. 2. Virtually no maintenance. 3. Stainless steel is claimed to be algae-proof. 4. Periodic replacement of the f i l l is not required. 5. Operation at highe maximum for wood-fil The proposed stainless steel cooling tower is being installed as part of an evaporation system which includes a single-effect evaporator. The single-effect evaporator is rated to evaporate 15,000 lbs./hr. of water; the associated cooling tower has a similar evaporative capacity. Thus, the cooling tower acts as a second evaporator effect. Since the installed cost of the singleeffect evaporator is estimated to cost $650,000 and that of the cooling tower, $100,000, the combined system has a substantial capital cost advantage. A summary of the design performance and physical data for the test and proposed cooling towers is shown in Table I. A similar application of cooling towers has recently been reported Q) ( 2 ) . In both cases, the cooling tower is used as a "finishing" step of an evaporation process, utilizing the sensible heat of the solution from prior high temperature evaporation steps. Acknowledgment to D. M. Rock and F. J . Fisher, of the American Enka Company, who conceived and carried out the program described in this paper. References 1. Horton, Ν. H. and Kunel, K. L . , "System Evaporates 27,000 Lb./Hr. With High Pressure Steam," Chemical Ρrocessing, Vol. 38, No. 11, p. 17, 1975. 2. Farin, W. G., "Low-Cost Evaporation Method Saves Energy By Reusing Heat," Chemical Engineering, Vol. 8 3 , No. 6, p. 101, 1976.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

18 Improved Polyester Radial Tire Yarn for Material, Pollution, and Energy Savings MICHAELJ.COLLINS Celanese Fibers Marketing Co., Charlotte, NC

A new polyester tir which significantl reduce pollution, and dip cost ed for carcass reinforcement of passenger radial tires. This pro duct, designated T-865, i s adhesive activated and dimensionally stabilized. It is designed to give good adhesion to rubber with conventional RFL dipping at temperatures as low as 420°F. Standard, non-adhesive activated polyester typically requires either an isocyanate pre-dip or RFL dip additives to achieve acceptable adhesion. These adhesion promoters are expensive, require high treating temperatures and, in most cases, produce polluting by-products. The combination of adhesive activation and dimensional stability offers the potential for significant energy savings by allowing the use of lower treating temperatures and fewer zones. The dimensional stability of this product allows standard modulus­ -shrinkage properties to be achieved at these lower treating temperatures. One zone treatments at temperatures of 420°F are feasible, resulting in energy savings of well over 50%. This product can also be utilized to obtain improved radial tire uniformity, using standard treating temperatures. Review of Standard Polyester Tire Cord Treating General Description. High tenacity polyester fiber i s sold to the tire industry in yarn form. This yarn i s single and ply twisted into specific cord constructions and woven into fabric. The fabric is adhesive dipped and heat treated under controlled conditions of temperature, time, and tension. The specific treating conditions used are determined by the adhesive system and the final fabric physical properties which are required. Normally, polyester requires treating temperatures in the range of 465 480°F to achieve desired adhesion levels and shrinkage/elongation (heat set) properties. Standard, non-adhesive activated polyester requires special dip systems to obtain satisfactory adhesion. Rayon and nylon f i bers have traditionally used resorcinol - formaldehyde latex dip 280 In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

18.

COLLINS

Improved

Polyester

Radial

Tire

Yarn

281

systems (RFL) f o r adhesion t o rubber. The r e s o r c i n o l formaldehyde (RF) forms a r e s i n network which p r o v i d e s adhesion between the f i b e r s u r f a c e and the l a t e x . The l a t e x rubber adhesion i s then formed d u r i n g the a c t u a l c u r i n g o f the t i r e . Because p o l y e s t e r has a much l e s s r e a c t i v e s u r f a c e and fewer s i t e s a v a i l a b l e f o r hydrogen bonding than rayon or n y l o n , standard RFL d i p s do not g i v e good adhesion w i t h non-adhesive a c t i v a t e d p o l y e s t e r . S p e c i a l d i p systems were developed f o r p o l y e s t e r to overcome t h i s problem. These systems i n v o l v e d e i t h e r an i s o c y a n a t e p r e - d i p o r RFL d i p a d d i t i v e s used to achieve a c c e p t a b l e adhesion. The most commonly used dip systems are d e s c r i b e d i n more d e t a i l . D-417/RFL Dip System. The D-417/RFL ( l ) d i p system i s a two dip system developed s p e c i f i c a l l y f o r p o l y e s t e r by DuPont. The p r e - d i p , designated D-417 c o n t a i n d phenol b l o c k e d i s o c y a n a t e , Hylene MP, ( F i g u r Dip s o l i d s t y p i c a l l y range from 4 to 6% w i t h a t o t a l dip pick-up o f 1 to 2.5%. A f t e r the f a b r i c i s dipped i n the D-417 bath, i t i s cured a t high temperature to unblock and a c t i v a t e the i s o c y a nate. Curing temperatures o f 460°F are normally r e q u i r e d t o achieve a c c e p t a b l e adhesion. During c u r i n g , phenol i s l i b e r a t e d as a by-product. Phenol represents 43% o f the t o t a l weight o f Hylene MP. At a dip pick-up l e v e l o f 2.0%, t h i s means t h a t approximately .8 l b s o f phenol i s l i b e r a t e d per 100 l b s o f t r e a t e d f a b r i c . O b v i o u s l y , t h i s phenol represents a s i g n i f i c a n t p o l l u t a n t which must be managed i n u s i n g t h i s system. The D-417/RFL was one o f the o r i g i n a l systems developed f o r p o l y e s t e r and has been used f o r many y e a r s . I t g i v e s e x c e l l e n t i n i t i a l adhesion; but i t i s expensive, p o l l u t a n t , and very s e n s i t i v e to t r e a t i n g c o n d i t i o n s . RFL Dip + A d d i t i v e s . Two RFL d i p a d d i t i v e s which a r e most commonly used with p o l y e s t e r are chemicals designated N3 (2) and H7 ( 3 ) . These substances, a g a i n , were designed s p e c i f i c a l l y f o r p o l y e s t e r adhesive t r e a t i n g . Both a d d i t i v e s are designed to improve the adhesion between the RF r e s i n and the f i b e r s u r f a c e to achieve good o v e r a l l adhesion. F a i r l y high l e v e l s o f these a d d i t i v e s (20 - 30%) and high t r e a t i n g temperatures (465 - 480°F) are r e q u i r e d to o b t a i n s a t i s f a c t o r y r e s u l t s . Other a d d i t i v e s used w i t h RFL dips f o r p o l y e s t e r i n c l u d e c e r t a i n i s o c y a n a t e s ( 4 ) . In a l l cases, these a d d i t i v e s are very expensive compared to the RFL dip and add s i g n i f i c a n t l y to the overa l l d i p c o s t . A l s o , each o f these a d d i t i v e s generate p o l l u t a n t by-products during f a b r i c heat treatment which, i n some cases, present major p o l l u t i o n c o n t r o l problems. T r e a t i n g C o n d i t i o n s . As i n d i c a t e d e a r l i e r , a f t e r the f a b r i c i s adhesive dipped, i t i s heat t r e a t e d under c o n d i t i o n s o f cont r o l l e d temperature, time, and t e n s i o n . These c o n d i t i o n s are designed t o achieve s p e c i f i c adhesion l e v e l s and f a b r i c p h y s i c a l properties. Typical treating conditions required for polyester are shown as f o l l o w :

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

POLYESTER

TIRE

CORD

YARN I

SINGLE PLY

FIRST

FIRST

CORD WEAVE

J

GREIGE FABRIC I

ADHESIVE DIP

I

HEAT SET

TREATED CALENDER with RUBBER

FABRIC I

J

CALENDERED

FABRIC

TIRES

GENERAL DESCRIPTION 1. 2. 3. 4.

System Developed By DuPont D-417 Predip - Isocyanate (Hylene M P ) & Epoxy Hylene MP Activates ( U n b l o c k s ) at 4 6 5 ° F Hylene MP Liberates 43% Phenol When Activated Figure!.

D-417 RFL dip system.

Hylene

MP.

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

18.

COLLINS

Improved Polyester Radial Tire Yarn

Temperature (°F) Time (Seconds) S t r e t c h (%)

Zone Ί 300 50 +2

283

Zone 2 Zone 3 "365 465" 50 50 0 -2

The f a b r i c goes from the f i r s t d i p tank i n t o Zone 1 where i t must be d r i e d . Zones 2 and 3 a t the h i g h e r temperatures are used t o heat s e t the f a b r i c to reduce shrinkage and o b t a i n the d e s i r e d dimensional s t a b i l i t y . The s t r e t c h - r e l a x c o n d i t i o n s o r t e n ­ sions are a d j u s t e d to achieve s p e c i f i c modulus/shrinkage proper­ t i e s a t given t r e a t i n g temperatures. The r e l a t i o n s h i p between t r e a t i n g temperature and shrinkage f o r standard p o l y e s t e r i s shown i n F i g u r e 2. The modulus/shrinkage r e l a t i o n s h i p at a given t r e a t i n g temperature i show i F i g u r 3 G e n e r a l l y t r e a t e d cord shrinkage must be q u i r i n g minimum t r e a t i n g temperatures o f 460°F f o r standard p o l y ester. Most t r e a t i n g u n i t s p r e s e n t l y use n a t u r a l gas as the primary energy source. R e c e n t l y , some o f these u n i t s have been m o d i f i e d to use e i t h e r f u e l o i l o r n a t u r a l gas due to the concern about a v a i l a b i l i t y o f n a t u r a l gas. A l s o , due t o concerns about energy a v a i l a b i l i t y and c o s t , most o f these companies have i n i t i a t e d major e f f o r t s aimed at energy c o n s e r v a t i o n i n t h e i r f a b r i c t r e a t ­ ing p r o c e s s e s . O b v i o u s l y , t o t a l energy r e q u i r e d f o r f a b r i c t r e a t ing i s a f u n c t i o n o f t r e a t i n g temperatures and dwell times. With standard p o l y e s t e r and e x i s t i n g adhesive systems, t h e r e i s very l i t t l e f l e x i b i l i t y i n terms o f energy c o n s e r v a t i o n . T-865 P o l y e s t e r T i r e Cord General D e s c r i p t i o n . A new p o l y e s t e r t i r e yarn which s i g ­ n i f i c a n t l y reduces energy, p o l l u t i o n , and d i p c o s t s d u r i n g f a b r i c t r e a t i n g has been developed f o r c a r c a s s r e i n f o r c e m e n t o f passen­ ger r a d i a l t i r e s . T h i s product, d e s i g n a t e d T-865, i s adhesive a c t i v a t e d and d i m e n s i o n a l l y s t a b i l i z e d . I t i s a s u r f a c e a c t i v a ­ ted product designed t o g i v e good adhesion t o rubber w i t h con­ v e n t i o n a l RFL d i p p i n g a t temperatures as low as 420 F. The com­ b i n a t i o n o f adhesive a c t i v a t i o n and dimensional s t a b i l i t y o f f e r s the p o t e n t i a l f o r s i g n i f i c a n t energy savings by a l l o w i n g the use o f lower t r e a t i n g temperatures and fewer t r e a t i n g zones. The dimensional s t a b i l i t y o f t h i s product allows standard modulus/ shrinkage p r o p e r t i e s t o be achieved a t these lower t r e a t i n g tem­ peratures ( 5 ) . One (1) zone treatments a t temperatures o f 420°F are f e a s i b l e r e s u l t i n g i n energy savings o f w e l l o v e r 50%. T-865 t r e a t i n g i s d e s c r i b e d i n more d e t a i l below. "RFL Only" Dip System. T-865 p o l y e s t e r i s s u r f a c e a c t i v a t e d t o e l i m i n a t e the need f o r the adhesion promoters which are r e ­ q u i r e d with s t a n d a r d p o l y e s t e r . The recommended RFL d i p formu­ l a t i o n i s shown i n Table I ( 6 ) . As i n d i c a t e d , i t i s b a s i c a l l y a standard RFL d i p s i m i l a r t o those used with rayon and n y l o n . 9

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

284

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY T Y P I C A L P O L Y E S T E R T I R F CORD T R E A T I N G S Y S T E M S

SYSTEM NUMBER

DIP

(1)

TEMP.

(°F)

TIME

(SEC.)

STRETCH

DIP

1

2

D-417

RFL + ADDITIVES

465

300

50

50

+1

+1

(%)

(2)

RFL

ZQNL2 TEMP.

(°F

TIME

(SEC.

STRETCH

CD

0

0

ZONE 3 TEMP.

(°F)

440

470

TIME

(SEC.)

50

50

-1

-1

STRETCH

Figure

2.

Shrinkage

(%)

vs. treating

temperature

for standard

polyester

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

Improved

COLLINS

Polyester

Radial

Tire

Yarn

8

ο ο

"'••ft

7

10 CO

6

LU

5 4

Ζ QC Χ LU LU QC

3 2 1 3.0

E Figure 3.

E

10

1 0

vs. shrinkage

7.0

(%)

far standard

TARLE

RFCOMMFNDED RFI

RESIN

6.0

5.0

4.0

polyester

I

BIP

FORMULATION

SOLUTION 365.0

WATER NAOH (50%)

2.6

RESORCINOL

16.6

FORMALIN (37%) TOTAL

AGE

FOR 1 3 / 4 HR. a

398.9

75°F

LATEX

V I N Y L P Y R I D E N E T Y P E (GENTAC 41%) SBR T Y P E ( P L I O L I T E

2000

215.0 53.8

41%)

AfiF D I P ?A HRS. B E F O R E USING

DESCRIPTION DIP

SOLIDS

- 20%

F/R

RATIO

-

RESIN/LATEX VP L A T E X / S B R DIP

1.2:1

- .20 LATEX -

SHELF L I F E

80/20

- TWO ( 2 ) WEEKS

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

286

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

G e n e r a l l y , t h e RFL f o r m u l a t i o n i s n o t c r i t i c a l although lower F/R r a t i o (1.2:1) and non-ammoniated dips a r e recommended. In some c a s e s , i t may be necessary t o o p t i m i z e the d i p f o r m u l a t i o n f o r the p a r t i c u l a r rubber compound being used t o o b t a i n good r e s u l t s . The r e l a t i o n s h i p between d i p pick-up and adhesion i s shown i n Figure 4. Based on trade e x p e r i e n c e , a d i p pick-up l e v e l o f 5 t o 6% i s recommended t o achieve the optimum combination o f adhesion and f a t i g u e p r o p e r t i e s . O b v i o u s l y , h i g h e r p i c k up l e v e l s can be used i f h i g h e r adhesion i s r e q u i r e d . T r e a t i n g C o n d i t i o n s . The s e n s i t i v i t y o f adhesion t o t r e a t i n g temperature f o r T-865 u s i n g an "RFL o n l y " d i p i s shown i n F i g u r e 5. As i n d i c a t e d , adhesion i s very i n s e n s i t i v e t o t r e a t i n g temperature i n the range 420 t o 480°F. T h i s means t h a t good adhesion can be achieved w i t h T-865 t t r e a t i n temperature lo as 420°F as compared t m a l l y r e q u i r e s much h i g h e temperatures (465 480°F) t o o b t a i good adhesion. F i g u r e 6 shows a comparison o f shrinkage ( a t cons t a n t modulus) versus t r e a t i n g temperature f o r T-865 and standard p o l y e s t e r . T h i s comparison shows t h a t , due t o the improved d i mensional s t a b i l i t y o f T-865, standard shrinkage l e v e l s can be achieved a t much lower t r e a t i n g temperatures (410°F) than a r e norm a l l y r e q u i r e d f o r n o n - s t a b i l i z e d p o l y e s t e r . Thus, the combinat i o n o f adhesion a c t i v a t i o n and improved dimensional s t a b i l i t y a l l o w T-865 t o be t r e a t e d a t temperatures as low as 420°F w h i l e s t i l l a c h i e v i n g adhesion and p h y s i c a l p r o p e r t i e s ( s h r i n k a g e / modulus) which a r e e q u i v a l e n t t o standard p o l y e s t e r t r e a t e d a t h i g h e r temperatures (465 - 480°F). A l s o , s i n c e T-865 r e q u i r e s much l e s s heat t o achieve standard p r o p e r t i e s , the number o f t r e a t i n g zones can be reduced. At t r e a t i n g temperatures as low as 420°F, i t a c t u a l l y becomes f e a s i b l e t o e l i m i n a t e the d r y i n g zone and use a one (1) zone treatment. Comparative t r e a t i n g s y s tems f o r T-865 and standard p o l y e s t e r are shown i n Table I I . Advantages o f T-865 T r e a t i n g . There are three major advantages o f T-865 t r e a t i n g versus standard p o l y e s t e r . These advantages are savings i n energy, p o l l u t i o n , and m a t e r i a l c o s t s , each o f which are d i s c u s s e d i n more d e t a i l below. M a t e r i a l Savings. T-865 t i r e c o r d t r e a t i n g o f f e r s s i g n i f i cant d i p c o s t savings by e l i m i n a t i n g the need f o r the adhesion promoters normally r e q u i r e d with p o l y e s t e r . These adhesion promoters are very expensive r e l a t i v e t o standard RFL d i p and thus s i g n i f i c a n t savings can be r e a l i z e d by e l i m i n a t i n g t h e i r use. A d i p c o s t comparison o f "RFL o n l y " system versus the most commonly used systems with standard p o l y e s t e r i s shown i n Table I I I . As i n d i c a t e d , d i p c o s t savings o f 3
In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

18.

COLLINS

Improved

Polyester

Radial

Tire

Yarn

287

Figure 4. Adhesion vs. % dip pick up for T-865

Figure

5.

Polyester adhesion vs. temperature for T-865

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

treating

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

385

405

425

445

465

485

TREATING TEMPERATURE (°F) CONCLUSION: STANDARD SHRINKAGE LEVELS CAN BE ACHIEVED WITH DIMENSIONALLY STABILIZED POLYESTER AT TREATING TEMPERATURES AS LOW AS 405°F. Figure

6. Shrinkage vs. treating temperature for dimensionally stabilized T-865 and standard polyester

TABLE

II

COMPARATIVE TREATING SYSTEMS FOR

T-865 AND STANDARD POI YFSTFR

SYSTEM NUMBER

DIP

2

3

STANDARD

T-865

T-865

RFL/H7

RFL

RFL

300

300

420

50

50

50

+2

+2

-1

465

465

50

50

0

-2

1

1ML1 TEMP. TIME

(°F) (SEC.)

STRETCH

ω

ML2 TEMP.

(°F)

TIME

(SEC.)

STRETCH

(%)

ZONE 3 TEMP. TIME

(°F) (SEC.)

STRETCH PROPERTIES

ADVANTAGES

(%)

465 50 -2 DIMENSIONALLY STABILIZED RADIAL

ENERGY

UNIFORMITY

SAVINGS

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

18.

Improved

COLLINS

Polyester

DIP

System

D-417/RFL

% Dip Pick

(Double)

N3/RFL

(Single)

H7/RFL

(Single)

CONCLUSION ;

Up

COST

Radial

Tire

Yarn

289

SUMMARY

A d d i t i v e (%) Of D i p P i c k Up

4.5

20

Additive Cost ( $ / L b . Of S o l i d s )

A d d i t i o n a l Cost Over RFL A l o n e ( C / L b . Of F a b r i c ) 2.9

3.25

ADHESIVE ACTIVATED POLYESTER USING CONVENTIONAL R F L DIPPING CAN RESULT IN DIP COST SAVINGS UP TO 3.1<:/Lb. OF TREATED FABRIC.

TEMPERATURE

GRADIENT

NORMAL CORD SPACING

TEMPERATURE

GRADIENT

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

290

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

TABLE

IV

COMPARATIVE T R E A T E D CORD OF

T - 8 6 5 AND STANDARD

STANDARD RUN

E

B

E

1

STRENGTH, L B S .

(%)

0

POLYESTER

1

BREAKING

(%)

SHRINKAGE

TENSION,

TREATING

T-865

2

3

1

2

3

33.1

32.2

31.9

31.5

30.4

30.2

17.2

19.8

21.3

16.0

18.6

20.4

4.4

5.5

6.3

4.4

5.9

6.3

7.4

6.4

5.3

5.3

3.6

3.1

(350°F)

'FREE' "0.05

PRQPFRTIES POLYESTER

%

G/D" % GRS.

3.1 780

2.0 540

1.7 460

2.0 700

1.3 400

1.0 370

CONDITIONS:

455°F 50

SECONDS

TENSION

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

18.

COLLINS

Improved

Polyester

Radial

Tire

Yarn

291

the D-417/RFL system produces phenol as a by-product (.8 l b , phenol/100 l b s . o f t r e a t e d f a b r i c ) which p r e s e n t s a major p o l l u t i o n problem. T-865 t r e a t i n g e l i m i n a t e s the phenol problem by e l i m i n a t i n g the need f o r t h i s p r e - d i p . The H7 and N3 RFL d i p a d d i t i v e s a l s o generate by-products which can cause p o l l u t i o n problems. The high t r e a t i n g temperatures (465 - 480°F) r e q u i r e d by a l l o f these dip systems cause v o l i t i l i z a t i o n o f f i b e r f i n i s h and polymer components and d i p components which r e s u l t i n p o l l u t i o n a s s o c i a t e d with s t a c k e m i s s i o n s . In many c a s e s , p o l l u t i o n c o n t r o l equipment such as s c r u b b e r s , c a t a l y t i c c o n v e r t e r s or e l e c t r o - s t a t i c p r e c i p i t a t o r s w i l l be r e q u i r e d t o meet Federal and S t a t e environmental s t a n d a r d s . Lower temperature t r e a t i n g u s i n g T-865 may e l i m i n a t e the need f o r some o f t h i s equipment. Energy S a v i n g s . Energ saving r e s u l t fro th lowe treat ing temperatures (420° u s i n g fewer t r e a t i n g zones. Using a one (1) zone treatment w i t h T-865 c o u l d r e s u l t i n energy s a v i n g s o f w e l l over 50%. T h i s energy s a v i n g s i s p a r t i c u l a r l y s i g n i f i c a n t because n a t u r a l gas i s p r e s e n t l y the main source o f energy f o r these t r e a t i n g u n i t s . Improved R a d i a l T i r e U n i f o r m i t y As d i s c u s s e d e a r l i e r , T-865 i s a d i m e n s i o n a l l y s t a b i l i z e d p o l y e s t e r which r e s u l t s i n lower s h r i n k a g e / h i g h e r modulus prop e r t i e s a t standard t r e a t i n g temperatures. A comparison o f modulus (E10) and s h r i n k a g e o f T-865 versus standard p o l y e s t e r i s shown i n F i g u r e 7 and Table IV. I t i s g e n e r a l l y b e l i e v e d i n the t i r e i n d u s t r y t h a t improved dimensional s t a b i l i t y o f the p o l y e s t e r w i l l t r a n s l a t e i n t o improved r a d i a l t i r e u n i f o r m i t y . I f t h i s i s t r u e , T-865 t r e a t e d a t standard temperatures s h o u l d r e s u l t i n improved r a d i a l t i r e u n i f o r m i t y . L a r g e - s c a l e t r i a l s are now underway to see i f t h i s advantage does e x i s t . As shown e a r l i e r , F i g u r e 5, dimensional s t a b i l i t y i s d i r e c t l y r e l a t e d t o t r e a t i n g temperature. Thus, T-865 o f f e r s the f l e x i b i l i t y o f o p t i m i z i n g t i r e u n i f o r m i t y versus energy savi n g s . As t r e a t i n g temperature i s i n c r e a s e d , t i r e u n i f o r m i t y should i n c r e a s e a t the expense o f i n c r e a s e d energy usage. The r e l a t i v e economics o f t i r e u n i f o r m i t y versus energy c o s t and a v a i l a b i l i t y w i l l determine the optimum t r e a t i n g temperature. T h i s f l e x i b i l i t y i n t r e a t i n g temperature i s unique t o T-865 p o l y e s t e r because i t i s adhesive a c t i v a t e d and d i m e n s i o n a l l y stabilized. Conclusions A new p o l y e s t e r t i r e y a r n , d e s i g n a t e d T-865, which i s adh e s i v e a c t i v a t e d and d i m e n s i o n a l l y s t a b i l i z e d can be used to achieve s i g n i f i c a n t m a t e r i a l , p o l l u t i o n , and energy savings during f a b r i c t r e a t i n g . T h i s f i b e r can a l s o be t r e a t e d a t h i g h e r temperatures to achieve improved dimensional s t a b i l i t y which s h o u l d t r a n s l a t e i n t o improved r a d i a l t i r e u n i f o r m i t y .

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

292

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

Literature Cited (1) E.I. DuPont de Nemours & Co., U.S. Patent 3,307,966. (2) Canadian I n d u s t r i e s L t d . , U.S. Patent 3,318,750. (3) Imperial Chemical I n d u s t r i e s L i m i t e d , "Pexul: f o r Bonding Polyester F i b e r s to N a t u r a l and S y n t h e t i c Rubbers." R193 (1971). (4) Goodyear T i r e and Rubber Company, U.S. Patent 3,268,467. (5) Collins, M.J., I n t e r n a t i o n a l S o c i e t y o f I n d u s t r i a l Yarn Manufacturers Meeting, "Adhesive A c t i v a t e d Polyester for Material, Pollution, and Energy Savings." (1975) (6) Celanese F i b e r s Marketing Company, T e c h n i c a l Bulletin TBI 22 (1972).

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

INDEX

A Absorption, carboxyl determination b y silver 103,106 A b s o r p t i o n of w a t e r b y w o o d 31 A c c e l e r a t o r w e i g h t loss 71 N-Acetyl-cysteine-methylamide, r e a c t i o n of dyestuff w i t h 168 N-a-Acetyl-lysine-methylamide, reaction of dyestuff w i t h 168 Acid -catalyzed grafting 198,200-202 of e t h y l acrylate t o w o o l 202 m e c h a n i s m of 200 of m e t h y l methacrylate a n d acrylonitrile to w o o l 201 of monomers to w o o l 200 styrene c o m o n o m e r studies utilizing 201,203 of styrene to w o o l 199 photosensitized g r a f t i n g of styrene t o w o o l f a b r i c 214 r a d i a t i o n g r a f t i n g ... 205,206 of styrene to w o o l 206 -enhanced photosensitized g r a f t i n g 214,215 radiation grafting 206-208 styrene c o m o n m e r r a d i a t i o n grafting 207,208 n e u t r a l i z a t i o n of the p a d - b a k e controls 90,91 plus r a d i a t i o n a n d c o m o n o m e r techniques, g r a f t i n g f r o m emulsions u s i n g .... 209 structure i n c a t a l y z e d g r a f t i n g , effect of 199 Acrylonitrile 59,201 A-cubebene 113,120 A d h e s i o n , polyester 287 A d s o r p t i o n of l i q u i d water, differential heat of 25 A d s o r p t i o n of n i t r o g e n , surface area measurement b y 21 A f t e r w a s h finishing route, p a d - c u r e .. 194 A i r , effect of 9,211 <*,/?-Amic a c i d 81,85 Ammonia concentration of f a b r i c 65,70 treatments 67 of cotton fabrics, l i q u i d 63

Ammonia (continued) water, s w e l l i n g of b l e a c h e d cotton poplin fabric i n l i q u i d 64 A m m o n i u m succinamate 88 A m m o n i u m sulfamate catalyst 102 Application 182 i n the m i l l 249,264 A q u e o u s solution, photosensitized grafting f r o m 215

Β B a k e t i m e , free D S as a f u n c t i o n of .... 93 B a k i n g of the p a d - b a k e controls 90,91 Baratte reaction 82,96,98 Beetle, E u r o p e a n e l m b a r k 115,121 B E T equation 21 B i o d e g r a d a b i l i t y of synthetic polymers b y microorganisms 73 B i o d e g r a d a b l e fiber-forming p o l y m e r s 73 Biodégradation methods 74 Birch, white 250 B l e a c h a b i l i t y of spruce p u l p s 245 B l e a c h e d kraft, c o n v e n t i o n a l l y 250 B l e a c h e d o x y g e n p u l p , ozone 249,250 Bleaching, pulp 229 B o a r d , U . S . c o n s u m p t i o n of 242 B o l l w o r m moths, p h e r o m o n e t r a p p i n g of p i n k 122,124 B o n d r u p t u r e , fibers after 259 B o n d i n g agents , 258 Bonding, hydrogen 39,189 B r e a k i n g strength f o r N o r w a y spruce 248 Brightness of spruce p u l p s , k a p p a number 245 B u r s t effect p o r t i o n of the release curve 113 B u r s t factor f o r N o r w a y spruce 248 f - B u t y l catechol, r a d i a t i o n g r a f t i n g i n presence of 204 B u t y l stéarate, f r i c t i o n a l properties of 155 B y - p r o d u c t s , u t i l i z a t i o n of 272

C C a l c i u m acetate methods, c a r b o x y l determinations b y 103,106 C a p i t a l , a v a i l a b i l i t y of 224 C a p i t a l costs 224

295

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

296

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

Caprolactam recovery 276 Carbohydrate-water interface 27 Carbon dioxide 272 Carbon tetrachloride, release rate of .. 117 Carboxyl determinations 103,106 Catalyst, ammonium sulfamate 102 Cellulose 3 concentration of free radicals in irradiated 50 differential heat of water sorption .. 23 DP loss of wood 104 Fe /H 0 -acrylonitrile system, free radical formation in 59 film 235 graft polymerization with irradiated 52 grafting system, free radicals generated in 5 hemisuccinate 88 derivatives, infrared analyses of .. 87 interactions of solutes with 35 internal pore water available in chopped cotton 36 irradiated in nitrogen, dried 48 pores, internal surfaces, and the water interface 20 saturated with aqueous monomer solution and photolyzed, cotton 55 sodium thiosulfate solutions contacted with 31 source 83 types of water in 28 Cellulosic substrates, inaccessible water in 34 Cellulosics, fabrics made from 81 Cellunier-F, Baratte reaction with mercerized 96, 98 Chain extension 140 Charge, electrostatic 39 Charge patch model 260 Chlorination/resin processes 176 Chlorine 230 Chymotrypsin 77 Color 253 remaining of peroxide-to-methyl ratios for milled-wood lignin .. 257 Co γ-radiation initiation 46,49 Comonomer, styrene 201,205,207,208 Comonomer techniques, grafting from emulsions using 209 Conductivity, viscose 4 Conservation 272 Cooling towers 277,278 Copolymerization of vinyl monomers 46 Cord properties, treated 290 T-865 polyester tire 283 treating, standard polyester tire 280 2+

60

2

2

Cost(s) capital 224 operating 224 summary, dip 289 Cotton cellulose, internal pore water available in chopped 36 cellulose I saturated with aqueous monomer solution and photolyzed 55 copolymerization studied by ESR spectroscopy 46 fabrics, liquid ammonia treatment of 63 growth of 135 heat of wetting of 24 impregnated with solutions of inaccessible water in 33 linters 34 poplin in liquid ammonial water, swelling of bleached 64 restretching of 68,70 shrinkage of bleached 66 shrinkage and elongation of 67 prices of 137 sorption of water vapor and organic vapors by 21 Coulter counts, comparison of HIAC 9 Creosol with alkaline hydrogen peroxide, reaction of 254 Cross section versatility 132 Crosslinking reactions with the urea, polvsulfonium bromide 189 Crosslinks, polydisulfide 191 Cure-afterwashfinishingroute, pad- 194 Cure via formation of polydisulfide crosslinks 191 Curing the polymers on the fabrics, conditions for 182 Curing reaction 188 of the sulfonium group 189 D Dacron polyester 129 Dibasic ester (DBE) 272 2,2-Dichlorovinyl-0,0-dimethyl phosphate (DDVP) 112 jV,N-Diethyl succinamic acid with mercerized Cellunier-F, Baratte reaction of 96,98 Differentialflowtest 16 at constantflowrate and constant pressure 17 forfilteredand unfiltered viscose .... 18 Difluorochloropyrimidine dyestuff 162 Diluting viscose, effect of 11

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

297

INDEX

2,4-Dimethyl-5-ethyl-6,8-dioxabicyclo (3.2.1) octane 119 Dip cost summary 289 Dip systems, D-417/RFL 281 Dissociation constant 169 Dissociation, enthalpy of 169 Disubstitution of the dyestuff 165 ( Ζ ) -9-Dodecenyl acetate 123 Dose-response data for pheromone trapping of pink bollworm moths 124 DP (degrees of polymerization) 82 effects of treatment conditions on .92,94 loss of wood cellulose 104 Drying 230 fabric temperature during 70 smooth 190 DS (degree of substitution) 81 effects of treatment condition as a function of bake time and temperature 93 Durability of nylon and polyesters .... 130 Dyeing of wool, reaction rates in reactive 162 Dyes, reaction of proteins with reactive 162 Dyes, sites for acid 131 Dyestuff (I) 165,172 with N-acetyl-cysteine-methylamide and N-a-acetyl-lysinemethylamide 168 with glycine-methylamide, reaction of 168 mono- and disubstitution of the 165 reactions of the secondfluorineof .. 172 Ε Ε. argutanus

123

EfRciencv, process 272 Elastic fibers 139 Electrostatic charge 39 Elm bark beetle, European 115 pheromone components, release rate of 121 Elongation of cotton poplin fabric .... 67 Elution volume of glucose 38 Elution volumes for solutes 38 Emulsion grafting 209, 212 End capping 140 Energy availability of 224 conservation 226,230,276 consumption 236,237, 272 excess 25 savings 280,291 Enthalpy of dissociation 169 Entropy decrease 25 Environmental control 226, 230

ESR spectroscopy, copolymerization studied by 46 Ethyl acrylate, grafting 205 with irradiated celluloses 52 with styrene 204 to wool 202,207,210 F

Fabric(s) application of prepolymers 177 from cellulosics 81 concentration of ammonia on the .... 65 conditions for curing the polymers on the 182 cotton 63 poplin 64,66,67,70 single jersey 190 temperature during drying 70 wool 177,213,214,216 -worsted 193 Fatty acid esters 156,159 Feedstock 236 Felting shrinkage 191,193 Ferric chloride-photosensitized methanol-methylacrylate glass, free radicals in 57 Fiber(s) carbon 145 cellulosic 20 chemical pulp 259 chemically resistant 138 cotton 21,33 elastic 139 -fiber bonds, shrink-resistance 194 finishes 153 -forming polymers, biodegradable .. 73 gelatin 75 graphite 143 high temperature resistant 136 hollow Ill man-made 127,135,147,271 maximum modulus values for 149 maximum tenacity values for 148 -to-metal frictional properties 156 nylon-6 276 polyacrylonitrile (Orion) 129 polynosic 33 polyolefin 129 production, energy consumption in 272 rayon 21 reinforcing 141,144 secondary 227 specialty 134 with tailor-made characteristics, second generation 130 Teflon 138 tire 142

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

298 Fiber(s)

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

(continued)

TMP 259 vapor dispensing to insect pheromones 118 wood 227 Film, cellulose 235 Film, polypropylene 235 Filter, candle 10 Filterability tests 10 Filtered viscose, differential flow test for 18 Filtering, effect of 13,16 Filtration laws 14 Finishes, fiber 153 Finishes, nonfuming spin 153 Finishing of cellulosicfibers,chemical 20 easy-care 6 route, pad-cure-afterwash 194 Flame resistance requirements 136 Flexural rigidity 191,193,194 Flow test, differential 16-18 Fluorine of dyestuff, reactions of the second 172 Flux, vapor 113 Fluxes for materials of different hollowfibersizes 114 Formation, nonwoven mat 84 Free energy 25 Free radical(s) in ferric chloride-photosensitized methanol-methacrylate glass 57 formation 46 in cellulose I-Fe /H 0 acrylonitrile system 59 in methacrylic acid-y-irradiated cellulose grafting system 52 in irradiated cellulose 50 Frictional properties,fiber-to-metal... 156 Frictional properties of vegetable oils vs. butyl stéarate and mineral oil 155 Fuming test 161 2+

G

2

2

Grafting acid-catalyzed (see Acid-catalyzed grafting) acid enhancement in radiation effect of contact time on effect of exposure to air on effect of liquor ratio on emulsion .... effect of monomer concentration on effect of temperature on from emulsions of ethyl acrylate to wool methacrylic acid-y-irradiated cellulose photosensitized ( see Photosensitized grafting) pre-irradiation studies of procedures, experimental of styrene and ethyl acrylate of styrene to wool in acidified methanol solution Grape berry moth orientation disruption tests Graphite fibers

207 211 211 212 212 211 209 210 52 210 197 204 198 124 143

H

Hand of treated fabrics 191 Handsheet, TMP 263 Hardwood lignin models 256 Heat settability ... 130 Heat treatment temperature on carbonfibers,effect of 145 Hemicellulose extract, 'Masonex' 232 Hemisuccinate derivatives, cellulose .. 87 HIAC particle count 5,8,9 Humidity, relative 25 Husbandry, responsible 271 Hydrogen bonding 39,189 Hydrogen peroxide reaction of creosol with 253 reaction of hardwood lignin models with 256 solution of 4-methylsyringol treated with 256 172 35 Hydrolysis of dyestuff (I) 167 74 Hydrolysis, reaction rate of 158 75 Hydrophile-lipophile balance Hydroxyl radical initiation .49,58

Gel permeation method Gelatin, cross-linked Gelatinfibers,tensile properties ... Glass, free radicals in ferric chloridephotosensitized methanolmethacrylate 57 Glucose, elution volume of 38 Glycine-methylamide, reaction of Ice-like-ness dyestuff with 168 Industry (ies) Glymes 37 paper Gossyplure 122 plastics Graft polymerization of ethyl acrylate pulp with irradiated celluloses 52 rubber

I

39 223,225,232 232 225 333

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

INDEX

299

Inflation 224,236 Infrared analyses of cellulose hemisuccinate derivatives 87 Initiation, Co γ-radiation 46,49 Initiation, hydroxyl radical 58 Insect pheromones, application of hollowfibervapor dispensing to 112,118 Insecticide DDVP ( 2,2-dichlorovinyl0,0-dimethyl phosphate) 112 Interface, carbohydrate-water ... 27 Interface, cellulose-water 20 y-Irradiated cellulose grafting system, methacrylic acid52 Isocyanate functionality 181

Methacrylic acid-y-irradiated cellulose grafting system 52 Methanol 205 -methylacrylate glass, ferric chloride-photosensitized 57 solution, grafting of styrene to wool in acidified 198 -water solution on concentration of free radicals, effect of 50 Methyl methacrylate to wool, acidcatalyzed grafting of 201 Methyl methacrylate to wool, radiation grafting of 208 Methyl ratios for milled-wood lignin, peroxide-to257 Methylacrylate glass, ferric chloridephotosensitized methanol57

Jersey fabric, single Jet hole plugging

iV-acetyl-cysteine168 IV-a-acetyl-lysine168 glycine168 4-Methyl-3-heptanol 113,119 4-Methylsyringol treated with hydrogen peroxide, solution of ... 256 Mill, application in the 249,264 Mineral oil, frictional properties of .... 155 Modification, chemical 261 Modulus values forfibers,maximum .. 149 Molecular diameter and weight of solute 36 Molecular size, solute exclusion by .... 32 Monomer(s) concentration on emulsion grafting, effect of 212 radiation grafting of 203 solution, cotton cellulose I saturated with aqueous 55 to wool acid-catalyzed grafting of 200 keratin using uv and y radiation, grafting of 197 photosensitized grafting of water-soluble 216 Monosubstitution of the dyestuff 165 Monosubstitution with pH and temperature, velocity of 167,168 Moth orientation disruption tests, grape berry 122,124 Moths, pheromone trapping of pink bollworm 124 Multistriatin 113,120

60

19 3

K test 10 Kappa number, brightness and bleachability of spruce pulps 245 Keratin, grafting of monomers to wool 197 Kevlar aramid 141 Kraft conventionally bleached 250 process 229 pulp 243,244,247,255 Kynol 138 w

Lignin, milled-wood Lignin models, hardwood Linters, cotton Lipophile balance, hydrophile— Liquor ratio on emulsions grafting, effect of Lubricants, vegetable oil Lycra Lysine-methylamide, Ν-α-acetyl-

257 256 34 158 212 154 139 168

M Macroglycol 140 Man-made fibers 127,147,271 Markets 236 'Masonex', a hemicellulose extract 232 Mat formation, nonwoven 84 Material pollution energy savings .280,286 Materials, release of various 114 Mechanical properties of carbon fibers 145 Mechanical pulping 241,253 Mercerized Rayocord-X-F 93 Metal frictional properties, fiber-to-.... 156 Methacrylate to wool using styrene, radiation grafting of 208

Ν

Neo structures Neutralization of the pad-bake controls, acid Nitrogen analysis dried cellulose irradiated in

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

155 90,91 103,105 48

300 Nitrogen

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

(continued)

measurements of surface areas by adsorption of Nomex aramid Nonyl phenols, ethoxylated Nucleophilicity of reactive groups of peptide models Nylon durability of Qiana Nylon-6 fibers Nylon-6,3Bz

21 136 158 170 127 130 131 276 76

Ο

Oak oxygen pulp, white 247 Oil consumption 23 lubricants, vegetable 154,155 mineral 155 prices, crude 237 tall 233 Operating costs 224 Organic vapors by cotton and rayon fibers, sorption of 21 Orientation disruption tests, grape berry moth 124 Orion ( polyacrylonitrilefibers) 129 Oxidation of its thiol groups, alkalinecatalyzed aerial 187 Oxygen < 242 -alkali pulping 229,241,242,247 pulp 241 ozone bleached 250 unbleached Norway spruce 244 unbleached white birch 243 white oak 247 Ozone-bleached oxygen pulp 249,250

Papermaking systems, dynamic Paralobesia viteana ( Clemons ), grape berry moth Particle count, HIAC Particles in viscose Patch model, charge Patch theory PectinophoragossypieUa

the pink bollworm

Pénicillium

(Saunders),

funiculosum

260 122 4,5,8 3 260 258 122

78

Peptide model(s) concentration of the 166 consumption of the 167 nucleophilicity of reactive groups .. 170 pK-values of 169,171 wool 162 Peroxide-to-methyl ratios for milled-

pH -dependence of reaction velocities .. 169 -independent reaction rates 169,171 velocity of monosubstitution with .. 168 Pheromone(s) application of hollowfibervapor dispensing to insect 118 components, elm bark beetle 121 and DDVP 112 dispenser, hollow fiber 124 trapping of pink bollworm moths ... 124 Photoinitiation 47,53 Photolyzed, cotton cellulose I 55 Photometric assessment of thin layer plates 165 Photosensitized grafting 213 acid enhanced 214, 215 from aqueous solution 215 of styrene to wool 213 of water-soluble monomers to wool 216 Photosensitized methanol-methylacrylate glass, ferric chloride- ... 57 pK-values of petide models 169,171 Ρ Plastics industries 232 Packaging 234 Polar surfaces, structure of water near 39,40 Pad Political forces 223 application, reactive polyalkylene 274 oxides for 176 Pollutants, air borne Pollution energy savings 280,286 -bake controls, baking, and saponi­ Polyacrylics 128,129 fication and acid neutralization 73,128 of the 90, 91 Polvacrylonitrile fibers (Orion) 129 -bake technique 85 (PAN) yarns 143 —cure—afterwashfinishingroute 194 Padding liquor 178,184 Polyalkylene oxides for pad application, reactive 176 PAN (polyacrylonitrile) yarns 143 Poly(amide-ester-urethane) 78 Paper 79 industry 223,225,232 Poly(amide-urethane) specification to end use Polyamides 76,128,136 requirements 231 Polybenzimidazoles 136 U.S. consumption of 242 Polycaprolactone 78 waste 227 Polycarbamoyl sulfonate 188,189

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

301

INDEX

Polydisulfides 189,191 Polyenamine 73 Polyester(s) 128,133 adhesion vs. treating temperature .. 287 Dacron 129 durability of 130 radial tire yarn, improved 280 shrinkage vs. treating temperature for standard 282 staple, prices of 137 tire cord, T-865 280,283 Polyethylene 133 glycol 33,156 Poly ( ethylene terephthalate) 128 Polyglycolate 74 Poly ( 2-hydroxyl-l,3-propylene sebacamide ) 77 Polyimide 13 Polyisocyanate 181,189 Polymer(s) 177 add-on 193 biodegradability of synthetic 73 biodegradable fiber-forming 73 on the fabrics, conditions for curing the 182 modification ... 132 new 76 shrink-resist 176,178 structure 179 Polymerization degree of (DP) 82,100 of ethyl acrylate with irradiated cellulose, graft 52 reactions 49 Polynosic fibers 33 Polyolefin fiber 129 Polyoxyethylene ethers 160 Polyoxyethylene glycol 156 Polvpropylene 133 film 235 isotactic 129 Poly (propylene oxide) 188 Poly(1.2-propylene sebacamide) 77 Polysulfonium bromide crosslinking reactions 189 Polytetrafluoroethylene 138 Polytetrahydrofuran 188 Poly(tetramethylene oxide) 188 Polythioglycollate 187,189 Polythiomalate 187 Polythiosulfate 187,189 Polyurea 77 Polyurethane 73 Poplin restretching of cotton 68, 70 shrinkage and elongation of cotton 66, 67 swelling of bleached cotton 64 Population trends 224 Populus hybrids 227

Pore(s) cellulose of cellulosicfibers,water in formation water available in chopped cotton cellulose, internal Preirradiation emulsion grafting Prepolymers to fabric, application of .. Pretension on shrinkage forces, effect of Pretreatment conditions Prices, crude oil Prices of polyester staple vs. cotton .... Process control development efficiency

227 20 20 21 36 212 177 67 84 237 137 226 226 272

forms, hollowfibercontrolled release 116 quality 230, 231 shifts 226 Production, viscose rayon 3 Propylene oxide derivatives, woolworsted fabric treated with 193 Protease Κ 77,79 Proteins with reactive dyes, reaction of 162 Pulp(s) with α,/3-amic acids, reaction of wood 81 bleaching 229 fibers after bond rupture, chemical 259 industry 225 kappa number brightness and bleachability of spruce 245 kraft 243,247,255 mill of the future 239 oxygen-alkali 247 ozone-bleached oxygen 250 Royselect-J 89 strength properties of treated 243,255,262 with succinamic acid, reaction of wood 82,104 synthetic 234 thermomechanical (TMP) 246,255 unbleached white birch oxygen 243 use of mechanical 241 white oak oxygen 247 Pulping chemical 229 groundwood 229 mechanical 253 oxygen 241 oxygen-alkali 241,242 process, sulfite 232 of TMP 252 of wood 227

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

302

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

Sheet density for Norway spruce 248 Sheet structures, preparation of 133 Shrink-resist effectiveness 184 Shrink-resist polymers for wool 176,178 R Shrink-resistant offiber-fiberbonds .. 194 Radiation grafting 203 Shrinkage area felting 191 acid-catalyzed 205 of cotton poplin fabric 66,67 acid enhancement in 207 felting 193 from emulsions using acid 209 forces, effect of pretension on 67 of ethyl acrylate 205 for standard polyester 282 mechanism of... 203,206 Sieving action 39 of methyl methacrylate to wool using styrene 208 Silver absorption, carboxyl determinations by 103,106 of monomers 197,203 246 styrene comonomer 205, 208 Simplification of styrene to wool 204 Slack swollen cotton poplin, restretching of 68 Rate(s) calculation of reaction 16 223 constants, pH independent 169 Social forces 67 of hydrolysis, reaction of 167 Sodium hydroxide treatments 30,31 of monosubstitution, reaction 167 Sodium thiosulfate 140 pH-independent reaction 171 Soft segment 99 Raw materials, availability of 224 Solubility determinations Rayocord-X-F, mercerized 93 Solute(s) with cellulose, interactions of 35 Rayonfibers,sorption of water vapor elution volumes for 38 and organic vapors 21 exclusion 34 Rayon production, viscose 3 by molecular size 32 Release behavior 112 molecular diameter and weight of .. 36 Reaction mixture 166 Solvents, radiation grafting of styrene to wool in various 204 rates at different temperatures 170 rates in reactive dyeing of wool 162 Sorption by cellulose and wood, differential heat of water 23 Recycling sample, effect of air 9 Reemay 133 Sorption of water vapor and organic vapors by cotton and rayon fibers 21 Reinforcement of rubber and resins .... 141 46 Reinforcing fibers 141 Spectroscopy, ESR Spinfinishes,nonfuming 153 Release curve, "burst effect" portion of the .. 113 Spinnable derivatives, synthesis of .... 81 Spruce 251 devices, hollowfiberas controlled Norway 244,248 vapor 111,112,115,116 pulps, kappa number brightness rate of carbon tetrachloride 117 and bleachability of 245 rate of elm bark beetle pheromone 133 components 121 Spunbonded technology 182 of various materials 114 Steaming Residue 161 Stone groundwood TMP and kraft pulp 255 Resins, reinforcement of 141 Restretching of cotton poplin 68, 70 Strength characteristics of unbleached Rigidity, flexural 191,193,194 Norway spruce oxygen and Rovselect-J pulp 89 kraft pulps 244 Rubber industry 233 characteristics of unbleached white Rubber, reinforcement of 141 birch oxygen and kraft pulps .. 243 properties of treated pulps 262 S values for stone groundwood TMP Saponification of the pad-bake and kraft pulp 255 controls 90,91 Stress-strain behavior of reinforcing Saponified sample 88 fibers 144 Scolytus multistriatus (Marsham) 115,119 Stress-strain curves, tire yarn 142 Sex attractant of the pink bollworm .. 122 Structure, polymer 179 Q

Qiana nylon

131

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

303

INDEX

Structure of water near polar surfaces 39,40 Styrene comonomer 207 grafting, acid 201,203 radiation grafting, acid 204,205,207,208 technique 201 and ethyl acrylate, radiation grafting of 204 to wool, grafting of 198,199,204,206,213,214 Substitution, degree of (DS) 81 Subtilisin 77 Succinamic acid 88 reaction of wood pulp with 82,104 Sugars, absorption of water by wood from solutions of 3 Sulfite pulping process 232 Sulfonium group, curing reactions of the 189 Sulfur 230 analysis 103,105 Surface(s) areas by adsorption of nitrogen, measurements of 21 of cellulose, internal 20 structure of water near polar 39, 40 Swelling of bleached cotton poplin fabric 64 Swelling, development of tension during 66 Τ

"Τ" test Tall oil Tear factor for Norway spruce Teflon fibers Temperature dependence of pK values of peptide models during drying, fabric free DS as a function of on free radical formation, effect of .. on grafting, effect of polyester adhesion vs. treating reaction rates at different . resistantfibers,high for standard polyester, shrinkage vs. treating velocity of monosubstitution with .. Tenacity valus forfibers,maximum .. Tensile properties of gelatin fibers strength mean strength-modulus relations for tire fibers

10 233 248 138

Tension during swelling, development of ~ 7.'. Γ. Test methods Testing of biodegradable fiberforming polymers Thermal expansion coefficients Thermomechanical pulp (see TMP) Thin layer plates, photometric assessment of Thiol groups, alkaline-catalyzed aerial oxidation of Threshold treatment level (TTL) Time, bake Time, contact Tire cord, T-865 polyester ;

66 178 73 24

165 187 184 93 211 283

relations for 142 radial 141,280,291 uniformity, improved 291 yarn, improved polyester radial 280 yarn stress-strain curves 142 TMP 246 fibers after bond rupture 259 handsheet 263 pulp, strength values for stone groundwood 255 pulping of 252 Toxicological effects 274 Treating conditions 281,286 Treatment conditions, effect of 90,92,94,101,102 Typar 133 Tyvek 133 U

Urea, crosslinking reactions with the .. 189 U.S. pulp and paper industry 223,225 Use requirements, match paper specifications to end 231

171 70 93 V 59 211 Vapor dispensing to insect pheromones, 287 170 application of hollowfiber...117,118 136 flux 113 release devices, hollowfibersas 28 controlled Ill, 112,115 168 Varnish 161 148 Vegetable oil lubricants 154,155 Velocities, pH-dependence of reaction 169 75 Velocity of monosubstitution with pH 71 and temperature 168 Vinyl monomers with cotton, copolymerization 46 142

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

304

TEXTILE AND PAPER CHEMISTRY AND TECHNOLOGY

Viscose Weight loss, accelerotor 71 conductivity 4 Wetting of cotton, heat 24 differentialflowtest forfilteredand White birch oxygen pulps, unfiltered 18 unbleached 243 effect of diluting 11 Wood particles in 3 cellulose, DP loss of 104 process, alternative to the 81 differential heat of water sorption rayon production 3 by 23 fiber, yields of 227 pulp with α,β-amic acids, reaction W of 81 pulp with succinamic acid, reaction Washability, level of 184 of 82,104 Waste paper 227 pulping of 227 Waste water treatments 273 residues 227 Water from solutions of sugars, absorption bound 22 of water by in cellulose, types of 2 in cellulosic substrates, inaccessibl application of grafted in chopped cotton cellulose, fabrics 177 internal pore 36 grafting of in cotton and polynosic fibers ethyl acrylate to 202, 207 polyethylene glycol, methyl methacrylate and inaccessible 33 acrylonitrile to 201,208 differential heat of adsorption of .... 25 monomers 200, 216 as a function of concentration of styrene to 198,199, 204,206, 213,214 sodium thiosulfate solutions, water-soluble monomers to 216 non-solvent 31 keratin, grafting of monomers to .... 197 interface, carbohydrate27 peptide models, reactions of a interface, cellulose 20 difluorochloropyrimide near polar surfaces, structure of 39, 40 dyestuff with 162 non-solvent 29 reaction rates in reactive dyeing of 162 in pores of cellulosic fibers 20 shrink-resist polymers for 176 solution on free radicals in substrates, application of preirradiated cellulose, effect of polymers to unchlorinated 177 methanol50 -worsted fabric treated with poly­ sorption by cellulose and wood, propylene oxide derivatives ...: 193 differential heat of 22 Woven worsted 190 swelling of bleached cotton poplin Wrinkling, resistance to 129 fabric in liquid ammonial 64 treatments, waste 273 vapor by cotton and rayon fibers, sorption of 21 Yarn, improved polyester radial tire .. 280 by wood from solutions of sugars, Yarn stress—strain curves, tire 142 absorption of 31 Yields of wood fiber 227

In Textile and Paper Chemistry and Technology; Arthur, J.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.