Rubber Analysis ї Polymers, Compounds and Products

Report 139

Rubber Analysis Polymers, Compounds and Products M.J. Forrest

Volume 12, Number 7, 2001

RAPRA REVIEW REPORTS A Rapra Review Report comprises three sections, as follows: 1. A commissioned expert review, discussing a key topic of current interest, and referring to the References and Abstracts section. Reference numbers in brackets refer to item numbers from the References and Abstracts section. Where it has been necessary for completeness to cite sources outside the scope of the Rapra Abstracts database, these are listed at the end of the review, and cited in the text as a.1, a.2, etc. 2. A comprehensive References and Abstracts section, resulting from a search of the Rapra Abstracts database. The format of the abstracts is outlined in the sample record below. 3. An index to the References and Abstracts section, derived from the indexing terms which are added to the abstracts records on the database to aid retrieval.

Source of original article Title

Item 1 Macromolecules

33, No.6, 21st March 2000, p.2171-83 EFFECT OF THERMAL HISTORY ON THE RHEOLOGICAL BEHAVIOR OF THERMOPLASTIC POLYURETHANES Pil Joong Yoon; Chang Dae Han Akron,University The effect of thermal history on the rheological behaviour of ester- and ether-based commercial thermoplastic PUs (Estane 5701, 5707 and 5714 from B.F.Goodrich) was investigated. It was found that the injection moulding temp. used for specimen preparation had a marked effect on the variations of dynamic storage and loss moduli of specimens with time observed during isothermal annealing. Analysis of FTIR spectra indicated that variations in hydrogen bonding with time during isothermal annealing very much resembled variations of dynamic storage modulus with time during isothermal annealing. Isochronal dynamic temp. sweep experiments indicated that the thermoplastic PUs exhibited a hysteresis effect in the heating and cooling processes. It was concluded that the microphase separation transition or order-disorder transition in thermoplastic PUs could not be determined from the isochronal dynamic temp. sweep experiment. The plots of log dynamic storage modulus versus log loss modulus varied with temp. over the entire range of temps. (110-190C) investigated. 57 refs.

Location

GOODRICH B.F. USA

Authors and affiliation

Abstract

Companies or organisations mentioned

Accession no.771897

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Previous Titles Still Available Volume 1

Volume 4

Report 3

Advanced Composites, D.K. Thomas, RAE, Farnborough.

Report 37

Report 4

Liquid Crystal Polymers, M.K. Cox, ICI, Wilton.

Polymers in Aerospace Applications, W.W. Wright, University of Surrey.

Report 5

CAD/CAM in the Polymer Industry, N.W. Sandland and M.J. Sebborn, Cambridge Applied Technology.

Report 39

Polymers in Chemically Resistant Applications, D. Cattell, Cattell Consultancy Services.

Report 8

Engineering Thermoplastics, I.T. Barrie, Consultant.

Report 41

Failure of Plastics, S. Turner, Queen Mary College.

Report 11

Communications Applications of Polymers, R. Spratling, British Telecom.

Report 42

Polycarbonates, R. Pakull, U. Grigo, D. Freitag, Bayer AG.

Report 12

Process Control in the Plastics Industry, R.F. Evans, Engelmann & Buckham Ancillaries.

Report 43

Polymeric Materials from Renewable Resources, J.M. Methven, UMIST.

Report 44

Flammability and Flame Retardants in Plastics, J. Green, FMC Corp.

Volume 2 Report 13

Injection Moulding of Engineering Thermoplastics, A.F. Whelan, London School of Polymer Technology.

Report 45

Composites - Tooling and Component Processing, N.G. Brain, Tooltex.

Report 14

Polymers and Their Uses in the Sports and Leisure Industries, A.L. Cox and R.P. Brown, Rapra Technology Ltd.

Report 46

Quality Today in Polymer Processing, S.H. Coulson, J.A. Cousans, Exxon Chemical International Marketing.

Report 47

Report 15

Polyurethane, Materials, Processing and Applications, G. Woods, Consultant.

Chemical Analysis of Polymers, G. Lawson, Leicester Polytechnic.

Report 16

Polyetheretherketone, D.J. Kemmish, ICI, Wilton.

Report 17

Extrusion, G.M. Gale, Rapra Technology Ltd.

Report 49

Report 18

Agricultural and Horticultural Applications of Polymers, J.C. Garnaud, International Committee for Plastics in Agriculture.

Blends and Alloys of Engineering Thermoplastics, H.T. van de Grampel, General Electric Plastics BV.

Report 50

Report 19

Recycling and Disposal of Plastics Packaging, R.C. Fox, Plas/Tech Ltd.

Automotive Applications of Polymers II, A.N.A. Elliott, Consultant.

Report 51

Report 20

Pultrusion, L. Hollaway, University of Surrey.

Biomedical Applications of Polymers, C.G. Gebelein, Youngstown State University / Florida Atlantic University.

Report 21

Materials Handling in the Polymer Industry, H. Hardy, Chronos Richardson Ltd.

Report 52

Polymer Supported Chemical Reactions, P. Hodge, University of Manchester.

Report 22

Electronics Applications of Polymers, M.T.Goosey, Plessey Research (Caswell) Ltd.

Report 53

Weathering of Polymers, S.M. Halliwell, Building Research Establishment.

Report 23

Offshore Applications of Polymers, J.W.Brockbank, Avon Industrial Polymers Ltd.

Report 54

Health and Safety in the Rubber Industry, A.R. Nutt, Arnold Nutt & Co. and J. Wade.

Report 24

Recent Developments in Materials for Food Packaging, R.A. Roberts, Pira Packaging Division.

Report 55

Computer Modelling of Polymer Processing, E. Andreassen, Å. Larsen and E.L. Hinrichsen, Senter for Industriforskning, Norway.

Volume 3

Report 56

Plastics in High Temperature Applications, J. Maxwell, Consultant.

Report 25

Report 57

Joining of Plastics, K.W. Allen, City University.

Report 58

Physical Testing of Rubber, R.P. Brown, Rapra Technology Ltd.

Report 59

Polyimides - Materials, Processing and Applications, A.J. Kirby, Du Pont (U.K.) Ltd. Physical Testing of Thermoplastics, S.W. Hawley, Rapra Technology Ltd.

Foams and Blowing Agents, J.M. Methven, Cellcom Technology Associates.

Volume 5

Report 26

Polymers and Structural Composites in Civil Engineering, L. Hollaway, University of Surrey.

Report 27

Injection Moulding of Rubber, M.A. Wheelans, Consultant.

Report 28

Adhesives for Structural and Engineering Applications, C. O’Reilly, Loctite (Ireland) Ltd.

Report 60

Report 29

Polymers in Marine Applications, C.F.Britton, Corrosion Monitoring Consultancy.

Volume 6

Report 30

Non-destructive Testing of Polymers, W.N. Reynolds, National NDT Centre, Harwell.

Report 61

Food Contact Polymeric Materials, J.A. Sidwell, Rapra Technology Ltd.

Report 31

Silicone Rubbers, B.R. Trego and H.W.Winnan, Dow Corning Ltd.

Report 62

Coextrusion, D. Djordjevic, Klöckner ER-WE-PA GmbH.

Report 63

Conductive Polymers II, R.H. Friend, University of Cambridge, Cavendish Laboratory.

Report 64

Designing with Plastics, P.R. Lewis, The Open University. Decorating and Coating of Plastics, P.J. Robinson, International Automotive Design.

Report 32

Fluoroelastomers - Properties and Applications, D. Cook and M. Lynn, 3M United Kingdom Plc and 3M Belgium SA.

Report 33

Polyamides, R.S. Williams and T. Daniels, T & N Technology Ltd. and BIP Chemicals Ltd.

Report 65

Report 34

Extrusion of Rubber, J.G.A. Lovegrove, Nova Petrochemicals Inc.

Report 66

Report 35

Polymers in Household Electrical Goods, D.Alvey, Hotpoint Ltd.

Reinforced Thermoplastics - Composition, Processing and Applications, P.G. Kelleher, New Jersey Polymer Extension Center at Stevens Institute of Technology.

Report 67

Report 36

Developments in Additives to Meet Health and Environmental Concerns, M.J. Forrest, Rapra Technology Ltd.

Plastics in Thermal and Acoustic Building Insulation, V.L. Kefford, MRM Engineering Consultancy.

Report 68

Cure Assessment by Physical and Chemical Techniques, B.G. Willoughby, Rapra Technology Ltd.

Report 69

Toxicity of Plastics and Rubber in Fire, P.J. Fardell, Building Research Establishment, Fire Research Station.

Report 70

Acrylonitrile-Butadiene-Styrene Polymers, M.E. Adams, D.J. Buckley, R.E. Colborn, W.P. England and D.N. Schissel, General Electric Corporate Research and Development Center.

Report 71

Rotational Moulding, R.J. Crawford, The Queen’s University of Belfast.

Report 72

Advances in Injection Moulding, C.A. Maier, Econology Ltd.

Report 94

Compressive Behaviour of Composites, C. Soutis, Imperial College of Science, Technology and Medicine.

Report 95

Thermal Analysis of Polymers, M. P. Sepe, Dickten & Masch Manufacturing Co.

Report 96

Polymeric Seals and Sealing Technology, J.A. Hickman, St Clair (Polymers) Ltd.

Volume 9 Report 97

Rubber Compounding Ingredients - Need, Theory and Innovation, Part II: Processing, Bonding, Fire Retardants, C. Hepburn, University of Ulster.

Report 98

Advances in Biodegradable Polymers, G.F. Moore & S.M. Saunders, Rapra Technology Ltd.

Report 99

Recycling of Rubber, H.J. Manuel and W. Dierkes, Vredestein Rubber Recycling B.V.

Volume 7 Report 73

Reactive Processing of Polymers, M.W.R. Brown, P.D. Coates and A.F. Johnson, IRC in Polymer Science and Technology, University of Bradford.

Report 74

Speciality Rubbers, J.A. Brydson.

Report 75

Plastics and the Environment, I. Boustead, Boustead Consulting Ltd.

Report 100 Photoinitiated Polymerisation - Theory and Applications, J.P. Fouassier, Ecole Nationale Supérieure de Chimie, Mulhouse.

Report 76

Polymeric Precursors for Ceramic Materials, R.C.P. Cubbon.

Report 101 Solvent-Free Adhesives, T.E. Rolando, H.B. Fuller Company.

Report 77

Advances in Tyre Mechanics, R.A. Ridha, M. Theves, Goodyear Technical Center.

Report 102 Plastics in Pressure Pipes, T. Stafford, Rapra Technology Ltd.

Report 78

PVC - Compounds, Processing and Applications, J.Leadbitter, J.A. Day, J.L. Ryan, Hydro Polymers Ltd.

Report 103

Report 79

Rubber Compounding Ingredients - Need, Theory and Innovation, Part I: Vulcanising Systems, Antidegradants and Particulate Fillers for General Purpose Rubbers, C. Hepburn, University of Ulster.

Report 80

Anti-Corrosion Polymers: PEEK, PEKK and Other Polyaryls, G. Pritchard, Kingston University.

Report 81

Thermoplastic Elastomers - Properties and Applications, J.A. Brydson.

Report 82

Advances in Blow Moulding Process Optimization, Andres Garcia-Rejon,Industrial Materials Institute, National Research Council Canada.

Report 83

Molecular Weight Characterisation of Synthetic Polymers, S.R. Holding and E. Meehan, Rapra Technology Ltd. and Polymer Laboratories Ltd.

Report 84

Rheology and its Role in Plastics Processing, P. Prentice, The Nottingham Trent University.

Gas Assisted Moulding, T.C. Pearson, Gas Injection Ltd.

Report 104 Plastics Profile Extrusion, R.J. Kent, Tangram Technology Ltd. Report 105 Rubber Extrusion Theory and Development, B.G. Crowther. Report 106 Properties and Applications of Elastomeric Polysulfides, T.C.P. Lee, Oxford Brookes University. Report 107 High Performance Polymer Fibres, P.R. Lewis, The Open University. Report 108 Chemical Characterisation of Polyurethanes, M.J. Forrest, Rapra Technology Ltd.

Volume 10 Report 109 Rubber Injection Moulding - A Practical Guide, J.A. Lindsay. Report 110 Long-Term and Accelerated Ageing Tests on Rubbers, R.P. Brown, M.J. Forrest and G. Soulagnet, Rapra Technology Ltd.

Volume 8

Report 111

Polymer Product Failure, P.R. Lewis, The Open University.

Report 85

Ring Opening Polymerisation, N. Spassky, Université Pierre et Marie Curie.

Report 112 Polystyrene - Synthesis, Production and Applications, J.R. Wünsch, BASF AG.

Report 86

High Performance Engineering Plastics, D.J. Kemmish, Victrex Ltd.

Report 113 Rubber-Modified Thermoplastics, H. Keskkula, University of Texas at Austin.

Report 87

Rubber to Metal Bonding, B.G. Crowther, Rapra Technology Ltd.

Report 114 Developments in Polyacetylene - Nanopolyacetylene, V.M. Kobryanskii, Russian Academy of Sciences.

Report 88

Plasticisers - Selection, Applications and Implications, A.S. Wilson.

Report 115 Metallocene-Catalysed Polymerisation, W. Kaminsky, University of Hamburg.

Report 89

Polymer Membranes - Materials, Structures and Separation Performance, T. deV. Naylor, The Smart Chemical Company.

Report 116 Compounding in Co-rotating Twin-Screw Extruders, Y. Wang, Tunghai University.

Report 90

Rubber Mixing, P.R. Wood.

Report 117 Rapid Prototyping, Tooling and Manufacturing, R.J.M. Hague and P.E. Reeves, Edward Mackenzie Consulting.

Report 91

Recent Developments in Epoxy Resins, I. Hamerton, University of Surrey.

Report 118 Liquid Crystal Polymers - Synthesis, Properties and Applications, D. Coates, CRL Ltd.

Report 92

Continuous Vulcanisation of Elastomer Profiles, A. Hill, Meteor Gummiwerke.

Report 119 Rubbers in Contact with Food, M.J. Forrest and J.A. Sidwell, Rapra Technology Ltd.

Report 93

Advances in Thermoforming, J.L. Throne, Sherwood Technologies Inc.

Report 120 Electronics Applications of Polymers II, M.T. Goosey, Shipley Ronal.

Volume 11 Report 121 Polyamides as Engineering Thermoplastic Materials, I.B. Page, BIP Ltd. Report 122 Flexible Packaging - Adhesives, Coatings and Processes, T.E. Rolando, H.B. Fuller Company. Report 123 Polymer Blends, L.A. Utracki, National Research Council Canada. Report 124 Sorting of Waste Plastics for Recycling, R.D. Pascoe, University of Exeter. Report 125 Structural Studies of Polymers by Solution NMR, H.N. Cheng, Hercules Incorporated. Report 126 Composites for Automotive Applications, C.D. Rudd, University of Nottingham. Report 127 Polymers in Medical Applications, B.J. Lambert and F.-W. Tang, Guidant Corp., and W.J. Rogers, Consultant. Report 128 Solid State NMR of Polymers, P.A. Mirau, Lucent Technologies. Report 129 Failure of Polymer Products Due to Photo-oxidation, D.C. Wright. Report 130 Failure of Polymer Products Due to Chemical Attack, D.C. Wright. Report 131 Failure of Polymer Products Due to Thermo-oxidation, D.C. Wright. Report 132 Stabilisers for Polyolefins, C. Kröhnke and F. Werner, Clariant Huningue SA.

Titles Available in the Current Volume Volume 12 Report 133 Advances in Automation for Plastics Injection Moulding, J. Mallon, Yushin Inc. Report 134 Infrared and Raman Spectroscopy of Polymers, J.L. Koenig, Case Western Reserve University. Report 135 Polymers in Sport and Leisure, R.P. Brown. Report 136 Radiation Curing, R.S. Davidson, DavRad Services. Report 137 Silicone Elastomers, P. Jerschow, Wacker Chemie GmbH. Report 138 Health and Safety in the Rubber Industry, N.Chaiear, Khon Kaen University.

Rubber Analysis – Polymers, Compounds and Products M. J. Forrest (Rapra Technology Ltd)

ISBN: 1-85957-305-3

Rubber Analysis – Polymers, Compounds and Products

Contents 1

Introduction .............................................................................................................................................. 5 1.1 Additional Information ........................................................................................................................ 5

2

Analytical Techniques .............................................................................................................................. 5 2.1 Wet Chemistry Techniques .................................................................................................................. 5 2.2 Specific Instrumental Techniques ........................................................................................................ 6 2.3 Spectroscopic Techniques .................................................................................................................... 6 2.3.1 Infrared (IR) Spectroscopy .................................................................................................... 6 2.3.2 Ultraviolet Light Spectroscopy .............................................................................................. 8 2.3.3 Nuclear Magnetic Resonance (NMR) Spectroscopy ............................................................. 8 2.3.4 Atomic Absorption Spectroscopy (AAS) ............................................................................... 8 2.3.5 X-Ray Fluorescence Spectroscopy (XRF) ............................................................................. 8 2.3.6 Chemiluminescence Spectroscopy ......................................................................................... 8 2.4 Chromatographic Techniques .............................................................................................................. 9 2.4.1 Gas Chromatography-Mass Spectrometry (GC-MS) ............................................................. 9 2.4.2 Gas Chromatography (GC) .................................................................................................... 9 2.4.3 High Performance Liquid Chromatography (HPLC) ............................................................ 9 2.4.4 Gel Permeation Chromatography (GPC) ............................................................................... 9 2.4.5 Thin Layer Chromatography (TLC) ...................................................................................... 9 2.5 Thermal Techniques ........................................................................................................................... 10 2.5.1 Differential Scanning Calorimetry (DSC) ........................................................................... 10 2.5.2 Dynamic Mechanical Thermal Analysis (DMTA) ............................................................... 10 2.5.3 Thermogravimetric Analysis (TGA) .....................................................................................11 2.6 Elemental Techniques .........................................................................................................................11 2.7 Microscopy Techniques ..................................................................................................................... 12 2.8 Miscellaneous Techniques ................................................................................................................. 12

3

Characterisation of Rubber Polymers ................................................................................................. 12 3.1 Determination of Molecular Weight .................................................................................................. 12 3.1.1 Gel Permeation Chromatography (GPC) ............................................................................. 12 3.1.2 Viscosity ............................................................................................................................... 14 3.1.3 Osmometry ........................................................................................................................... 14 3.1.4 Light Scattering .................................................................................................................... 14 3.1.5 Miscellaneous Techniques ................................................................................................... 14 3.2 Monomer Types and Microstructure .................................................................................................. 15

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Rubber Analysis – Polymers, Compounds and Products

4

Determination of the Principal Components in a Rubber Compound ............................................. 15 4.1 Determination of the Base Polymer ................................................................................................... 15 4.2 Determination of Plasticiser/Oil ........................................................................................................ 18 4.3 Determination of Fillers ..................................................................................................................... 19 4.3.1 Carbon Black ....................................................................................................................... 19 4.3.2 Inorganic Fillers ................................................................................................................... 19

5

Carbon Black.......................................................................................................................................... 20 5.1 Analysis of Free Carbon Black .......................................................................................................... 21 5.1.1 Particulate and Aggregate Size ............................................................................................ 21 5.1.2 Total Surface Area ................................................................................................................ 21 5.1.3 External Surface Area .......................................................................................................... 22 5.1.4 Miscellaneous Analytical Techniques .................................................................................. 22 5.2 Analysis of Carbon Black in Rubber Vulcanisates ............................................................................ 22 5.2.1 Isolation of Carbon Black from a Vulcanisate ..................................................................... 22 5.2.2 Total Surface Area Tests on Recovered Black ..................................................................... 22 5.2.3 External Surface Area Test on Recovered Black ................................................................. 23 5.2.4 Quantification of Carbon Black in Rubber Vulcanisates ..................................................... 23 5.2.5 Dispersion of Carbon Black Within Rubber Products ......................................................... 23

6

Determination of Antidegradants in a Rubber Compound ............................................................... 24 6.1 UV Stabilisers .................................................................................................................................... 24 6.2 Antioxidants ....................................................................................................................................... 24 6.3 Antiozonants ...................................................................................................................................... 25

7

Determination of Cure System Additives and Their Breakdown Products ...................................... 26 7.1 Analysis of Uncured Samples ............................................................................................................ 26 7.2 Analysis of Cured Samples ................................................................................................................ 27

8

Determination of Miscellaneous Compound Additives ...................................................................... 28 8.1 Blowing Agents.................................................................................................................................. 28 8.2 Flame Retardants ............................................................................................................................... 29 8.3 Process Aids ....................................................................................................................................... 29 8.3.1 Plasticisers and Oils ............................................................................................................. 29 8.3.2 Factice .................................................................................................................................. 29 8.3.3 Resins ................................................................................................................................... 30 8.3.4 Pine Tar ................................................................................................................................ 30 8.4 Peroxide Co-agents ............................................................................................................................ 30

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Rubber Analysis – Polymers, Compounds and Products

9

Cure State Studies .................................................................................................................................. 31

10 Reverse Engineering and Product Deformulation .............................................................................. 32 10.1 Initial Suite of Tests ......................................................................................................................... 32 10.1.1 Quantitative Solvent Extraction ......................................................................................... 32 10.1.2 Ash Content ........................................................................................................................ 32 10.1.3 Thermogravimetric Analysis .............................................................................................. 32 10.1.4 Infrared Spectroscopy ........................................................................................................ 32 10.1.5 X-Ray Fluorescence Spectroscopy .................................................................................... 33 10.1.6 Gas Chromatography-Mass Spectroscopy ......................................................................... 33 10.2 Results From the Initial Suite of Tests ............................................................................................. 33 10.3 Additional Tests ............................................................................................................................... 37 10.3.1 Elemental Determinations .................................................................................................. 37 10.3.2 Solid State Nuclear Magnetic Resonance .......................................................................... 37 10.4 Results From the Additional Tests ................................................................................................... 37 10.5 Summary of the Data on the Sample ............................................................................................... 38 11 Surface Blooms and Product Contaminants ....................................................................................... 39 11.1 Surface Blooms ................................................................................................................................ 39 11.2 Product Contaminants ...................................................................................................................... 40 12 Analysis of Rubber Latices ................................................................................................................... 40 12.1 Quality Control Tests ....................................................................................................................... 40 12.1.1 Alkalinity ............................................................................................................................ 40 12.1.2 pH ....................................................................................................................................... 40 12.1.3 Potassium Hydroxide Number ........................................................................................... 41 12.1.4 Volatile Fatty Acid Number (VFA) .................................................................................... 41 12.1.5 Carbon Dioxide Number .................................................................................................... 41 12.1.6 Non-Volatile Acids (NVA) ................................................................................................. 41 12.1.7 Higher Fatty Acids (HFA) .................................................................................................. 41 12.2 Chemical Stability Tests .................................................................................................................. 41 12.2.1 Natural Rubber Latices ...................................................................................................... 41 12.2.2 Synthetic Rubber Latices ................................................................................................... 41 12.3 Polymer Composition of Synthetic Latices ..................................................................................... 42 12.3.1 Bound Styrene Content ...................................................................................................... 42 12.3.2 Bound Acrylonitrile Content .............................................................................................. 42 12.3.3 Volatile Monomers ............................................................................................................. 42 12.4 Particulate Property Tests ................................................................................................................ 42

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Rubber Analysis – Polymers, Compounds and Products

12.4.1 Viscosity ............................................................................................................................. 42 12.4.2 Surface Tension .................................................................................................................. 42 12.4.3 Soap Content ...................................................................................................................... 43 12.4.4 Soap Deficiency ................................................................................................................. 43 12.4.5 Particle Size ....................................................................................................................... 43 12.5 Miscellaneous Chemical Tests ......................................................................................................... 43 13 Failure Diagnosis .................................................................................................................................... 43 13.1 Compositional Problems .................................................................................................................. 44 13.2 Contamination Problems.................................................................................................................. 44 13.3 Odour and Emissions Problems ....................................................................................................... 44 14 Conclusion .............................................................................................................................................. 45 Additional References ................................................................................................................................... 46 APPENDIX 1 Standard Nomenclature System for Rubbers .................................................................... 47 APPENDIX 2 International Rubber Analysis Standards (ISO) ............................................................... 49 APPENDIX 3 Glass Transition Temperatures of Rubbers ........................................................................ 54 APPENDIX 4 Maximum Service Temperatures and Relative Stabilities of Different Rubber Types to Various Degradation Agencies ......................................................................................... 55 APPENDIX 5 Solubility Parameters of Rubbers and Typical Solvents ................................................... 55 APPENDIX 6 Specific Gravities of Rubbers and Compounding Ingredients ......................................... 56 Abbreviations and Acronyms ....................................................................................................................... 58 References from the Rapra Abstracts Database ......................................................................................... 61 Index ............................................................................................................................................................. 137

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Rubber Analysis – Polymers, Compounds and Products

1 Introduction Rubber compounds present chemical analysts with one of their most difficult, but satisfying, challenges. In order to obtain useful products that perform under a variety of demanding conditions, the rubber matrix can be tailor made by selecting from a broad range of polymers and additives. In common with plastics, there is a wide range of polymer types available, which can also be blended together to further enhance properties. With rubbers, the possible compositional permutations are made more numerous by an extensive array of plasticisers, fillers, process aids, antidegradants and cure systems. Within one additive group alone, the carbon blacks, there are in excess of 30 different possible products. The technology of rubbers is therefore a mature one, allowing fine tuning of a compound to fit a number of seemingly conflicting design criteria and product requirements. The choice of constituents available also means that rubbers can be used in many applications, from bridge bearings to rubber seals, gaskets, adhesives and elastic cord. In addition to the traditional thermoset rubbers (i.e., vulcanised rubbers) there is also a number of thermoplastic rubbers where the crosslinks are physical as a result of a crystalline, or above ambient glass transition temperature, polymer component. The rubber analyst has therefore to bear in mind the complexity of the system and the possible interferences that may be brought into play. When reverseengineering a rubber compound a considerable number of elemental, spectroscopic, chromatographic and thermal techniques have to be used in an integrated and structured approach in order to accumulate and cross check the data necessary for a successful result. It is still the case, though, that even with the greatest care it is unlikely that more than 90-95% of a complex rubber formulation can be completely elucidated by analytical means alone. Some rubbers contain more than fifteen ingredients, some at a low (<1%) level, and others are very volatile, thermally labile or will have undergone chemical reactions during vulcanisation making accurate original quantifications impossible to deduce.

if at least some information is available on the sample and the types of species that may be present in it. Armed with this knowledge analysts can work much more efficiently and obtain better results. To assist in the acquisition of this knowledge, opportunities have been taken within the text to not only detail the analytical methods, but provide examples of the species that they may be used to detect and quantify. In other words, in order to have a full understanding of the principle of the analytical methods and approaches, it is vital to have an understanding of rubber technology itself.

1.1 Additional Information Relevant books and academic papers are cited throughout the review, but there are also a number of general texts which will provide useful further reading (335, 336, 341, 342, 343) (a.1-a.4). Appendices are attached which summarise the standard nomenclature system for rubbers (Appendix 1), international standards (ISO) on rubber analysis (Appendix 2) and key properties of rubbers and compounding ingredients: glass transition temperatures (Appendix 3) maximum service temperatures and relative stabilities (Appendix 4) solubility parameters (Appendix 5) specific gravities of rubbers and compounding ingredients (Appendix 6).

2 Analytical Techniques

2.1 Wet Chemistry Techniques Before the advent of modern instrumental techniques, rubber analysis relied on a sequence of wet chemistry reactions to determine information such as the generic polymer type of a compound. Classical organic methods were used constantly.

The objective of this review is to present, as fully as is possible within this format, an introduction to the techniques and methods that are used to carry out quality control work on rubbers, to investigate the failure of rubber products, and to deformulate rubber compounds.

The amount of wet chemistry carried out in the modern rubber analysis laboratory in the 21st Century is minimal. There are some tests which can still be grouped under this heading, although even some of these can employ an instrumental technique to provide the final answer.

With respect to the last category, the analyst’s job when characterising ‘unknowns’ is always made much easier

The determination of total sulfur and combined sulfur in rubber can be carried out using essentially the same

5

Rubber Analysis – Polymers, Compounds and Products

method; the only difference is that the combined sulfur is the sulfur that remains after a solvent extraction has been performed on the sample. There are a number of methods that can be used and workers have been developing approaches to the determination of sulfur in organic compounds since the 1890s. Two favourite methods are the furnace tube combustion method and the oxygen flask combustion method. The furnace tube method can be used on rubber samples that are fully compounded and contain chlorine and/or nitrogen. The sample is burnt in a stream of oxygen at very high temperatures (e.g., 1350 °C) to ensure that all the sulfur in the compound (even that in inorganic fillers such as barium sulfate) is included. Adding catalysts can reduce this temperature to around 1000 °C. If the contribution from inorganic additives is not desirable then catalysts can be left out and the test carried out at 1000 °C. The method is described in ISO 6528-3 (1988). The volatile products are trapped in a solution of hydrogen peroxide and then a titration carried out to a permanent pink colour using 0.01M barium perchlorate in a mixture of 80:20 (v/v) propan2-ol and water. The oxygen flask method (ISO 6528-1 (1992) and BS 7164-23.1 (1993)) also uses an initial burn in oxygen (although the sample is trapped between two platinum gauge ‘flags’) and trapping of the volatile products in hydrogen peroxide. Once the volatiles have been trapped, however, there is a choice of analytical method. A titration can be performed in the same way as for the furnace tube method, or ion chromatography can be used to quantify the sulfate ion. In the case of the titration approach care has to be taken as a number of interferences can take place. For example, zinc sulfate (produced during the combustion of zinc oxide or due to the oxidation of zinc sulfide) will dissolve in the hydrogen peroxide solution, and zinc ions in general will interfere with the end point; these have to be removed by sending the absorbent solution down through an ion exchange column. Even small amounts (e.g., 0.5%) of chlorine in a rubber will give low results due to the volatility of zinc chloride and hence its take up by the absorption solution. If the sample contains calcium carbonate, a change in the absorption solution is required to a mixture of 0.25 ml concentrated hydrochloric acid, 2 ml distilled water and 1 ml 6% hydrogen peroxide. This will dissolve the calcium sulfate formed and decompose any calcium carbonate. An ion exchange column is then used prior to the titration. These problems, which are also common to the furnace tube titration step, are completely removed by using ion chromatography.

6

The oxygen flask combustion technique can also be used for the determination of total halogens (titration method) or quantification of specific halogens (ion chromatography method) in a rubber. The absorbing solution would typically comprise 1.5 ml of 0.05M potassium hydroxide, 0.2 ml of 30% hydrogen peroxide and 10 ml of distilled water. It is sometimes necessary to determine the amount of elemental sulfur remaining in a rubber. One method, the copper spiral method, is the subject of a standard (ISO 7269 (1995)); other methods include the sulfite method, polarography, and reverse phase high performance liquid chromatography (HPLC) with acetonitrile:water gradient elution and ultraviolet (UV) detection at 270 nm.

2.2 Specific Instrumental Techniques A specific analyser which is very useful in the analysis of rubbers is the Carbon:Hydrogen:Nitrogen (CHN) analyser. Its ability to quantify nitrogen on relatively small samples (e.g., 50 mg) in an efficient and cost effective way is invaluable in attempts to quantify the amount of acrylonitrile in a nitrile rubber (NBR) and in calculation of blend ratios of NBR and polyvinyl chloride (PVC) blends. A recent international standard has been published (ISO 15672, 2000) which deals with the determination of the total nitrogen content of a sample using an automated analyser. No specific manufacturer’s instrument is specified, the standard concentrates on the experimental procedure to be used. A standard has also recently been published (ISO 15671, 2000) which deals with the determination of the total sulfur content of a sample using an automated analyser. Again, no specific instrument is specified and the standard concentrates on the experimental procedure.

2.3 Spectroscopic Techniques

2.3.1 Infrared (IR) Spectroscopy IR spectroscopy is used extensively in the analysis of rubbers. It is a very good, relatively quick technique for the determination of the polymer present in a rubber compound. The majority of rubber compounds contain additives such as carbon black and plasticisers that can interfere with the infrared data obtained, if an attempt is made to analysis the compound directly. It is usually

Rubber Analysis – Polymers, Compounds and Products

necessary, therefore, to remove plasticisers, etc., from the sample matrix by using solvent extraction (e.g., using acetone or methanol) and to then pyrolyse the extracted portion and record an infrared spectrum from the collected pyrolysis condensates. This operation eliminates any interference from either carbon black or inorganic additives and fillers. For this approach to be successful a database of pyrolysate infrared spectra, such as the one published by Rapra Technology (158), needs to be available. A standard pyrolysis infrared spectrum for natural rubber is shown in Figure 1. Analysis of the extract obtained during preparation of the sample for the pyrolysis technique by IR spectroscopy can be used to identify the plasticiser or

oil present in a compound. An IR analysis of an ash of the compound obtained by heating at 550 °C can help to identify inorganic fillers. IR spectroscopy can also be used to identify specialist additives such as fire retardants. Where the raw uncompounded polymer is to be investigated, it is possible to record an IR spectrum from either a film cast from solution, by direct transmission, or even the pyrolysate approach. The transmission infrared spectrum obtained by casting a film of natural rubber from a chloroform solution is shown in Figure 2.

Figure 1 Pyrolysate infrared spectrum of natural rubber

Figure 2 Transmission infrared spectrum of a film of natural rubber

7

Rubber Analysis – Polymers, Compounds and Products

The above examples refer to the common form of IR spectroscopy which relies on absorption of the infrared radiation, but it is also possible to use IR emission spectroscopy in the analysis of rubbers. This is essentially a qualitative technique where an infrared beam causes vibrations in the polymer molecules and the radiation emitted is analysed by a highly sensitive spectrometer. The advantage of the technique is that it can be used on carbon black filled vulcanisates and it has been employed in degradation studies. It is possible to qualitatively determine chemical changes, such as carbonyl formation (e.g., in acid groups), weight loss and volatilisation (loss of emission intensity due to the unzipping of the polymer), as well as the formation of conjugated double bonds and specific polymer reactions. The technique has been used to study surface oxidation after natural and accelerated heat ageing and the results obtained provided a rate of degradation by studying the vibration of chemical groups associated with the degradation. Although the data obtained by emission IR spectroscopy is not quantitative due to such interferences as sample reflectivity and re-absorbance in thicker samples, Pell and co-workers (330) have suggested an approximate relationship between absorbance and emittance.

2.3.2 Ultraviolet Light Spectroscopy Although not as universally used as IR, UV spectroscopy has a role to play in the analysis of polymers. It is used in the qualitative and quantitative analysis of additives, e.g., antioxidants and UV stabilisers.

2.3.3 Nuclear Magnetic Resonance (NMR) Spectroscopy NMR spectroscopy is a powerful tool for the determination of polymer structure. It is at its most sensitive when used on analytes in solution and so is very useful for analysis of the raw polymers. The vast majority of rubber compounds are, however, vulcanised and so either the NMR work has to be carried out on the fraction of the polymer which can be extracted using a strong solvent (chloroform) or a solid state (magic angle) system has to be used. The disadvantage of the latter is its lack of sensitivity, which can make the analysis of blends difficult. Of the conventional instruments, both proton and carbon-13 instruments have been used in rubber analysis.

8

2.3.4 Atomic Absorption Spectroscopy (AAS) This technique, and the related inductively coupled plasma (ICP) spectroscopy, is used where it is necessary to quantify metals in a rubber compound. Although not often required it can be of use in the analysis of flame retardant systems, where additives such as antimony trioxide and zinc borate have been used.

2.3.5 X-Ray Fluorescence Spectroscopy (XRF) This technique is very useful for obtaining semiquantitative elemental data from rubber compounds and their ashes. Among other things, it helps to identify inorganic fillers and pigments in samples. The technique is usually used in conjunction with IR spectroscopy. When it comes to analysing small samples, sample surfaces or contaminants in samples, the scanning electron microscope (SEM)/XRF combination (sometimes referred to as energy dispersive analysis (Edax)) can be a very valuable tool.

2.3.6 Chemiluminescence Spectroscopy Chemiluminescence analysis is suitable for studying the early stages of the thermal oxidation of rubbers. A weak emission of light formed by chemical reactions appears during the oxidative degradation of hydrocarbons. The weak light may originate from the deactivation of an excited carbonyl group formed during the oxidation, or from the formation of peroxide radicals. The use of a sensitive photon detector enables the chemiluminescence to be detected accurately and with good reproducibility. The intensity of the light emitted by the polymer is proportional to the concentration of the originating source. Thus, the degree of oxidation of the polymer can be assessed and the effectiveness of antioxidants evaluated. From the decrease in luminescence intensity it is possible to calculate the rate constant of the decay of the radicals in the polymer undergoing degradation and the effective activation energy for the initiation of oxidation. The imaging chemiluminescence technique (ICT) has proved to be a useful method to depth profile the oxidation of rubbers. The advantages of chemiluminescence are the relative simplicity of the equipment required, its high sensitivity and the short duration of the experiments. Tests can be

Rubber Analysis – Polymers, Compounds and Products

carried out either dynamically (at heating rates from 1 to 15 °C/min) or isothermally, with an upper temperature limit of 250 °C.

particularly the case with antioxidants such as Irganox 1010 and TMQ. HPLC also comes into its own in the quantification of plasticisers such as dioctyl phthalate (DOP).

2.4 Chromatographic Techniques 2.4.4 Gel Permeation Chromatography (GPC) 2.4.1 Gas Chromatography-Mass Spectrometry (GC-MS) This powerful, versatile technique can be used to obtain a significant amount of compositional information on rubber samples. It is particularly useful in identifying minor components of the sample such as the breakdown products of the cure system and the antidegradants. It can also be used to investigate the polymer fraction within a sample when the instrument is fitted with a pyrolysis unit set at around 600 °C. This technique plays a role in failure diagnosis by being able to provide information on chemicals which may cause odours, and organic contaminants that may have degraded the rubber matrix. There are a variety of ways that the sample or fractions of the sample (e.g., an extract) can be analysed by GCMS. These include static headspace, dynamic headspace, solution injection and pyrolysis.

2.4.2 Gas Chromatography (GC) This technique can also be used to obtain polymer type information by use of a pyrolysis approach, although the technique is less powerful because of the absence of a mass spectrometer; a pyrogram ‘fingerprint’ has to be used and a comparison made against a library of known standards. The technique is also used for the identification and quantification of additives such as antioxidants and, where sufficient volatility exists, plasticisers and organic flame retardants.

For this technique to be successful the sample must be readily soluble in an organic solvent. By definition then, this technique cannot be carried out on vulcanisates and even unvulcanised fully compounded rubber samples can present problems due to filler-rubber interactions. GPC is therefore a technique which tends to be restricted to the analysis of pure elastomeric polymers and in this, using solvents such as toluene and tetrahydrofuran, it is usually very successful. However, given that a number of rubbers are free radical polymerised (e.g., nitrile rubbers) or have very high molecular weights (e.g., natural rubber) there can be a problem with ‘gel’, which results from either chemical crosslinking or physical entanglements. In the case of some rubber systems (e.g., thermoplastic rubbers), the development of interfaces such as the Lab Connections LC Transform, have proved very useful in increasing the amount of information that can be obtained in a GPC analysis, by enabling IR data to be recorded on the resultant chromatogram. Hence, with the correct choice of separating column, polymer blends can be separated and identified as well as plasticisers. Figure 3 shows how high resolution GPC (using 100 Å, 10 μm columns) has been used to separate the polymeric and monomeric additives extracted from a nitrile rubber sample. Use of the LC transform technique enables the separated species to be identified.

2.4.5 Thin Layer Chromatography (TLC)

2.4.3 High Performance Liquid Chromatography (HPLC)

TLC is a relatively simple technique that can be used for both the separation and identification of additives such as antioxidants and UV stabilisers. A number of approaches are possible using different developing solvents and spraying agents.

HPLC can be used to identify and quantify additives that are either too involatile or insufficiently thermally stable to be analysed by GC or GC-MS. This is

TLC can also be used in a preparative way for the isolation of sample fractions for subsequent chromatographic or spectroscopic analysis.

9

Rubber Analysis – Polymers, Compounds and Products

Figure 3 Separation of polymeric and monomeric additives extracted from a nitrile rubber sample using high resolution GPC

2.5 Thermal Techniques

2.5.1 Differential Scanning Calorimetry (DSC) It is possible to use DSC to provide quality control fingerprint thermograms from which deviations in formulation can be ascertained. These will contain both endotherms from the volatilisation of ingredients such as plasticisers, together with exotherms from the curing of the rubber and the degradation of the sample. Figure 4 shows the range of events which can be observed by analysing an uncured compounded rubber by DSC under nitrogen over the temperature range -100 °C to + 600 °C. Additional events, such as oxidation, can be observed by using an oxidising atmosphere, e.g., air or oxygen. Using appropriate standard materials it is also possible to use DSC to quantify the level of certain additives, e.g., peroxides, in a sample.

10

DSC can be used in thermal stability studies of the rubber compound, and to investigate the effectiveness of antidegradants and fire retardants. DSC has also been used to profile the degree of cure through thick rubber articles and to study cure kinetics in general.

2.5.2 Dynamic Mechanical Thermal Analysis (DMTA) DMTA is very useful for generating modulus versus temperature data on rubber compounds. The effects of temperature on this important material property can be obtained over a wide temperature range (typically –150 °C to +200 °C), along with the glass transition temperature (Tg) and information on thermal stability. The sensitivity of DMTA to glass transition temperatures (approximately 1000 times greater than DSC which measures heat capacity changes rather than modulus) is very useful in the analysis of unknown

Rubber Analysis – Polymers, Compounds and Products

Figure 4 Typical events observed in the DSC trace of an uncured elastomer in nitrogen

blends of rubbers. For example, it can be difficult to positively detect the presence of 5-10% of polybutadiene in styrene-butadiene rubber by techniques such as IR (which would rely on the value of the total butadiene response alone), but the marked difference in the Tg values makes the presence of polybutadiene in such a matrix much easier to detect and, with appropriate standards, quantify.

Other uses for this technique include the production of compositional fingerprints for quality control purposes, and the investigation of thermal stability including the effects that additives such as flame retardants and antioxidants have on it. It is possible to interface modern TGA instruments directly to IR instruments or mass spectrometers, thus obtaining both quantitative and qualitative data in one analytical step.

2.5.3 Thermogravimetric Analysis (TGA) This technique is extremely useful in the analysis of compounded rubber samples. It is possible to obtain accurate quantifications of the principal compound constituents such as plasticiser, polymer, carbon black and inorganic species. This data can be obtained on small (e.g., 10 mg) samples in a relatively short time (around 45 minutes). By the use of the temperature maxima at which weight loss events occur, it is also possible to use the technique to obtain some qualitative assignments for the plasticiser and polymer. A typical TGA programme would be: Heat from ambient to 550 °C in a nitrogen atmosphere at 20 °C/min until no further weight loss occurs. Then, reduce the temperature to 300 °C, change the atmosphere to air and heat at 20 °C/min to 1000 °C. It is usually common to plot the weight loss derivative in conjunction with the weight loss. This can be used to detect the presence of a polymer blend of two or more components and to indicate if the sample contains more than one type of carbon black.

2.6 Elemental Techniques The determination of the concentration of certain elements can be very useful in rubber analysis work. In particular, it is often necessary to determine the amount of nitrogen or a halogen, such as chlorine or fluorine, in the calculation of polymer content or polymer blend proportions. The quantification of sulfur is useful in the differentiation between cure system types, and the targeting of specific elements can enable the quantity of certain additives (e.g., phosphate flame retardant or titanium dioxide pigment) to be calculated. The determination of nitrogen is usually done using CHN analysers. The technique is relatively simple and uses small amounts (e.g., 20-50 mg) of sample. With the other elements, the technique will vary according to the element being quantified. Sulfur and chlorine, for example, can be determined using oxygen combustion followed by ion chromatography analysis of the products. Other elemental techniques have been outlined in Sections 2.1, 2.2, 2.3.4 and 2.3.5.

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Rubber Analysis – Polymers, Compounds and Products

2.7 Microscopy Techniques

3.1 Determination of Molecular Weight

High magnification (e.g., 150x) optical microscopy can be used to examine the dispersion of fillers, such as carbon black, within the rubber matrix. The success of this operation is usually dependent on the generation of high quality microtome sections of the sample. The degree of dispersion can be subjectively compared to photographs of standard examples (e.g., Cabot Dispersion Classification Chart for carbon black).

In common with other polymers, rubbers have a distribution of molecular weights. This distribution will be widest for polymers produced by free radical polymerisation (e.g., nitrile rubbers) and narrowest for ionic polymers such as ethylene-propylene rubbers.

The technique of scanning electron microscopy has already been briefly mentioned in Section 2.3.5 in relation to the elemental analysis of surfaces in conjunction with XRF. It can also be used in its own right, where its high magnification powers can be employed to determine the particle size of fillers and in the detailed examination of fracture surfaces. Transmission electron microscopy (TEM) can be used to investigate the phase morphology of polymer blends and the dispersion of fillers.

2.8 Miscellaneous Techniques There are a number of other analytical techniques that can be used to characterise rubber samples. These include Raman spectroscopy (for structural analysis) (318, 321, 323) and direct probe mass spectroscopy (for the determination of high molecular weight antioxidants) (334). There are also specific techniques applied to the analysis of certain additives (e.g., carbon black), to particular rubber systems (e.g., latex), and to the rubber itself (e.g., viscosity measurement for determining molecular weight). These are mentioned in this review in the appropriate sections. Surface analysis techniques such as secondary ion mass spectrometry (SIMS) (194, 332), laser ionisation mass analysis (LIMA) (320, 324) and X-ray photoelectron spectroscopy (XPS) (192, 203, 266) are used for failure diagnosis work associated with such things as poor bonding to substrates.

It is possible to work with both raw rubbers, as well as compounded ones, although the production of an insoluble, infinite network by vulcanisation obviously precludes cured samples. There are a number of ways in which the molecular weight distribution of a rubber can be expressed:

M n = Number average molecular weight =

∑NM ∑N

M w = Weight average molecular weight =

∑NM2 ∑ NM

M z = Z average molecular weight =

∑NM3 ∑NM2

Where N = the total number of molecules of molecular mass M The Z average is very sensitive to high molecular weight molecules within the polymer. The weight average is always of greater value than the number average and a measure of the breadth of the molecular distribution of the polymer can be obtained by dividing the weight average by the number average: Polydispersity

=

Mw Mn

As the polymer tends towards uniform molecular weight the polydispersity approaches unity. There are a wide variety of methods that can be used to obtain molecular weights. The principal ones will now be described.

3.1.1 Gel Permeation Chromatography (GPC)

3 Characterisation of Rubbery Polymers

This is the preeminent technique and has been refined and developed extensively over the past 30 years.

This section covers analytical techniques that can be applied both to raw, uncompounded polymers and fully compounded materials.

It is possible to use it for both raw polymers and compounded ones and Mn, Mw and Mz values can be obtained. GPC is essentially a liquid chromatography

12

Rubber Analysis – Polymers, Compounds and Products

technique. The sample is dissolved in a suitable solvent (e.g., toluene for SBR; tetrahydrofuran (THF) for NBR) and injected into a system where the molecules are separated according to their molecular size by a column that contains a swollen, particulate, porous gel packing. The standard detector for GPC systems is the refractive index (RI) detector, but a feature of developments over the past 10 years is the development of double (RI and viscosity) or triple detector systems (RI, viscosity and light scattering). These multiple detection systems provide measures of ‘true’ molecular weight by obtaining actual Mark-Houwink parameters (in the case of the viscosity detector, see Section 3.1.2) for the polymer being analysed, as opposed to polystyrene equivalent molecular weight from the use of monodisperse polystyrene calibrants alone. An inherent property of the light scattering detector is that it provides ‘true’ molecular weight data. It is also possible to use spectroscopic detectors such as infrared and ultraviolet. One practical use of the latter is to determine if chemical modifiers (e.g., silane coupling agents) are bound to polymer molecules. This is done by measuring the molecular weight distribution of the modified rubber at a UV wavelength where the rubber itself does not contribute to the absorbance and comparing this to the distribution of the unmodified rubber.

There can be two problems encountered with the GPC of rubbers. The first is that rubbers can have relatively high molecular weights (Mw > 1,000,000) and care has to be taken that the flow rates used with modern small particle size packings (i.e., <10 μm diameter) do not cause the rubber molecules to break up under the imposed shear forces. Flow rates less than 0.5 ml/min may have to be used to minimise back pressure. The other problem is that free radical polymerised rubbers (and the natural product) can have a degree of insoluble crosslinked gel associated with them. GPC is often carried out on a comparative basis and Figure 5 illustrates this: the GPC chromatograms of two nitrile rubber samples in THF have been overlaid. In this case, it was thought that differences in processing performance were related to molecular weight differences. The molecular weight data computed from Figure 5 is shown in Table 1 and it can be seen that the difference is relatively insignificant.

Table 1 Molecular weight data for two nitrile rubber samples in THF Mw

Mn

Polydispersity

Sample A

281,000

89,800

3.1

Sample B

331,000

92,000

3.6

Figure 5 Overlaid GPC chromatograms of two nitrile rubbers

13

Rubber Analysis – Polymers, Compounds and Products

The use of the LC Transform module with GPC has extended its capabilities by allowing IR spectroscopy data to be generated on the species during the course of an analysis. This is done by impinging the species onto a germanium disc, which is then placed into a module fitted into the sample compartment of an IR bench. IR data is collected on the entire chromatogram using continuous collection software, which enables the IR spectrum of any particular section to be viewed. This technique is very useful for compounded rubbers as it allows polymer blends to be identified, as well as relatively high molecular weight additives such as plasticisers.

the solvent vapour. Calibration involves the analysis of standards of known molecular weight and should be over the entire molecular weight of interest to ensure the best results. The technique is useful for polymers that have molecular weights in the 500-50,000 range.

3.1.2 Viscosity

3.1.4 Light Scattering

This is a standard procedure for molecular weight determinations and involves the use of specially designed viscometers to accurately measure the viscosity of a polymer solution. From this the intrinsic viscosity is determined and hence the molecular weight. The time taken for the polymer solution to pass between two marks on the viscometer is compared to that of pure solvent and the ratio is the viscosity of the solution. Successive dilutions give a range of concentrations and times from which the intrinsic viscosity can be calculated. The value for this is then entered into the Mark-Houwink-Sakwada equation:

Recent developments in instrumentation have led to a resurgence of this technique: the weight average molecular weight is obtained from the light scattering behaviour of polymer solutions. These developments have centred on low angle laser light scattering (LALLS) (288), multi-angle laser light scattering (MALLS) (316, 317) and evaporative light scattering (ELS). As well as being stand alone instruments, light scattering detectors have been developed for GPC systems (see Section 3.1.1). MALLS detectors can provide direct information on the branching ratio of a polymer (a.5).

intrinsic viscosity = KMX where K and X are constants for the particular solvent being used and are referred to as the Mark-Houwink parameters. Depending on the source of the Mark-Houwink parameters the molecular weight can be expressed as either the number or weight average.

3.1.3 Osmometry There are two principal osmometry techniques (315, 345): vapour pressure osmometry and membrane osmometry. Vapour pressure osmometry involves the indirect measuring of the lowering of the vapour pressure of a solvent due to the presence of a solute. It is based on the measurement of the temperature difference between droplets of pure solvent and of polymer solution maintained in an isothermal atmosphere saturated with

14

Membrane osmometry involves the use of a membrane between the solvent and the polymer solution that is permeable to the solvent molecules but not to the solvated polymer molecules. This is the major restriction on the technique and means that it cannot be used for low molecular weight polymers (< approximately 50,000).

Care has to be taken to ensure that the polymer solution is clear (to reduce variability), low cell volumes (0.1 μl) and dilute solutions help this. Solvent choice is also critical, the best results being obtained with solvents that have a very different refractive index to the polymer, and that are low-scattering themselves. Evaporative light scattering involves the removal of the solvent from the solvated polymer as it elutes down a drift tube, the isolated polymer particles then scatter light from the light source. Light scattering can produce precise data and has been used successfully on polymers with molecular weights ranging from 10,000 to 10,000,000.

3.1.5 Miscellaneous Techniques Other methods of determining molecular weight include end group analysis (Mn), ultracentrifugation (Mw) and, indirect techniques by determining glass transition temperatures using DSC or DTA.

Rubber Analysis – Polymers, Compounds and Products

3.2 Monomer Types and Microstructure The use of pyrolysis IR spectroscopy and pyrolysis GC to determine the polymer type of a rubber is covered in Section 4.1. Where the rubber is uncompounded/unvulcanised the use of IR spectroscopy in transmission mode is very effective for identifying the minor monomers present in a rubbery polymer. For example, in the case of the terpolymer EPDM, transmission IR can be used on the pure polymer to identify the exact diene monomer used. However, if this rubber is compounded it may not be possible to remove enough of the additives to stop them masking the diene monomer in the rubber, and if the sample is vulcanised the diene monomer will have reacted with the cure system and so have been ‘lost’. Where appropriate standards are available it is also possible to use IR spectroscopy to quantify the amounts of monomers in copolymers, etc. It has been shown by Yamada and co-workers that high resolution pyrolysis GC can be used to both identify and quantify ethylidenenorbornene diene monomer in vulcanised EPDM rubbers (328).

the structure of vulcanised rubbers are Koenig and his team at Case Western Reserve University (208, 244, 337) and Gronski and co-workers at the University of Freiberg (326, 327, 329). The low density of the crosslinks present in a vulcanisate challenge the sensitivity of the technique, but it has still been possible to distinguish modifications to the main chain (isomerism and cyclic sulfides), the crosslinks themselves, and the reactions of cure and reversion (331).

4 Determination of the Principal Components in a Rubber Compound The term ‘principal’ here refers to the components which are present in the highest concentrations (including the base polymer), and which are not regarded as specialist (e.g., flame retardants). The latter are covered in Section 8.

4.1 Determination of the Base Polymer

NMR instruments can also be used to obtain fundamental structural information on polymers such as end group chemistry, branch points and structural isomerism (e.g., cis and trans 1,4-isomer ratios in diene rubbers). It is also possible to use IR spectroscopy for the latter example, although some of the isomeric structures have relatively weak absorptions which makes detection difficult when they are at a low concentration.

One of the most basic and useful tests to carry out on a rubber sample is to determine its rubber type. However, because the typical rubber compound only contains around 50% polymer a direct analysis by the most convenient technique, IR spectroscopy, rarely provides a definitive answer. A certain amount of preparation work is required to effectively remove the interference of the other major constituents. After milling or commuting the sample to increase surface area, a solvent extraction is performed to remove organic species such as plasticisers/oils and cure system/antidegradant system species. The extracted portion of the sample is then pyrolysed and an IR spectrum recorded of the collected pyrolysis condensates (see Figure 1). Providing that an extensive database of pyrolysate spectra is available (e.g., Rapra infrared spectra library (158)), this method is very successful in both differentiating between generic polymer types (e.g., natural rubber and SBR) and, in some cases, in telling the differences between grades of polymer (e.g., Viton A, Viton B and Viton G). It is also possible to use the technique to identify certain rubber blends, particularly blends of diene rubbers, and the results can be expressed semi-quantitatively if the appropriate standards are available.

Two sets of workers who have carried out a lot of work on the use of solid state carbon-13 NMR to investigate

Another method which enables the polymer type within a rubber sample to be identified is pyrolysis GC. This

Another technique that is very effective at identifying the exact monomers present is NMR. Although the best results are obtained on a solution of the pure polymer, it is possible to use the solid state technique on vulcanised samples and also to analyse extracts of these by carbon-13 NMR; the chemical composition of the oligomers being an accurate enough reflection of the original polymer. The NMR technique will also provide information on the proportions of the various monomers in copolymers and tripolymers. In contrast to IR spectroscopy this information can be obtained without having to analyse standards of known monomer composition; the areas under the diagnostic chemical shifts being used.

15

Rubber Analysis – Polymers, Compounds and Products

method can be applied to either the extracted portion of the sample or the sample as received. In the latter case the relatively low molecular weight oils, etc., elute early on and do not have a significant influence on the pyrogram as a whole. To avoid complications, it is advisable to use extracted samples. As with pyrolysis IR spectroscopy, a database of standards needs to be put together and then the pyrogram fingerprints of

unknowns can be matched. Reference fingerprint GC pyrograms for SBR and NR obtained at 750 °C are shown in Figures 6 and 7, respectively. The temperature that the pyrolysis unit is set at, and the design of the unit (e.g., Curie point or micro-furnace), will affect the pyrograms produced from a particular sample. Again, it is possible to identify and quantify blends and blend ratios.

Figure 6 GC pyrogram for SBR obtained at 750 °C

Figure 7 GC pyrogram for NR obtained at 750 °C

16

Rubber Analysis – Polymers, Compounds and Products

Typical experimental conditions for pyrolysis GC experiments are as follows:

However, care needs to be taken in interpretation of results as the following list of pyrolysis products of polychloroprene demonstrates:

Sample weights

0.1-5.0 mg

Pyrolysis temperatures

400-800 °C (microfurnace and Curie point)

chloroethene

800-1200 °C (platinum filament)

chloroprene

Microfurnace type pyrolyser - specific example using an SGE Pyrojector: Weight of sample

0.4 mg

Pyrolysis temperature

600 °C

Pyrolysis gas

Helium at 15 psi

GC column

5% Diphenyl siloxane 30 m x 0.25 mm, 1.0 μm film

GC column temperature programme 2 mins at 50 °C followed by 10 °C/min to 280 °C and then 10 mins at 280 °C GC carrier gas

Helium at 10 psi

GC injector temperature 320 °C Detector

Flame ionisation detector (FID) at 350 °C

Adding mass spectrometry into the system, so that the technique becomes pyrolysis GC-MS, further increases the usefulness of the method and the information that can be obtained. The following principal diagnostic pyrolysis species can be detected in pyrograms of rubbers: Rubber type

Species

Polyisoprene

Isoprene and dipentene

SBR

Butadiene, 4-vinyl-1cyclohexene and styrene

Polybutadiene

Butadiene and 4-vinyl-1cyclohexene

IIR

Isobutene and isoprene

Nitrile rubber

Butadiene, acrylonitrile and 4-vinyl-1-cyclohexene

It can be seen from the above list that rubbers will regenerate monomers and dimers upon pyrolysis under non-oxidising conditions (e.g., under helium).

butadiene

toluene styrene chlorobenzene 1-chloro-3-methylbenzene 4-chloro-1,2-dimethylbenzene The non-chlorinated species originate from the loss of hydrogen chloride followed by cyclisation in the case of the aromatic compounds. Common pyrolysis products can cause problems in trying to detect amounts of, for example SBR, in polychloroprene. It is therefore important to target secondary products as well as primary. In addition to identifying the polymer type of a rubber, pyrolysis GC can also be used to quantify the polymers in a blend. Fuh and Wang (221) used the peak ratio of 1chloro-4-(1-chloroethenyl)-cyclohexene from polychloroprene and benzonitrile from nitrile rubber to accurately quantify the two polymers in standards having blend compositions varying from 80:20 to 20:80. A recent review covering the use of pyrolysis IR spectroscopy, pyrolysis GC, solid state magic-angle spinning carbon-13 NMR and 300 MHz proton NMR to identify polymers in rubber samples was presented at the International Tyre Conference in Ohio (209). In addition to reviewing the subject, analysis results obtained using the four techniques on six prepared rubber samples by twelve laboratories are detailed. With respect to the quantification of the polymer component within a rubber, the easiest technique to use is TGA. It is also possible to detect a blend of polymers with TGA and to often obtain a semiquantification of the blend ratio by reference to the splitting of the weight loss derivative. Unfortunately, some rubber types (e.g., polychloroprene) undergo two stage weight loss processes when heated and the first stage (loss of hydrogen chloride) will overlap with the volatilisation of organics stage. It is therefore not possible to use TGA alone to determine the polymer content of these samples. Another complicating factor is that a number of rubber types (e.g., halogenated, nitriles, polyesters) do not

17

Rubber Analysis – Polymers, Compounds and Products

completely pyrolyse during the nitrogen atmosphere region and leave a carbonaceous residue which essentially oxidises to carbon dioxide in the air region. This carbonaceous residue, which may to an extent overlap with the carbon black weight loss, has to be included in order to obtain an accurate estimate of polymer content. Another route which involves a similar methodology to TGA, is tube furnace combustion. This method has the benefit, in certain circumstances, of using larger samples, but is ultimately more time consuming, and samples which have been quantitatively extracted have to be used.

4.2 Determination of Plasticiser/Oil Mention has already been made in Section 4.1 of the isolation of plasticisers from a rubber matrix by solvent extraction. In that case the objective was to clean up the polymer sample for further work. However, it can be an end in its own right and it is the subject of an international standard (ISO 1407), which shows how it is possible to obtain an accurate quantification of the plasticiser present in a compound.

Having quantified the plasticiser/oil present by extraction it is then possible to obtain identification by the use of transmission IR spectroscopy. There is an excellent database available (339), which enables an identification to be made. For example, the data shown in the spectra in Figures 8 and 9 is consistent for di(2-ethylhexyl) phthalate and triphenyl phosphate, respectively. Where the plasticisers have distinct IR spectra (e.g., phthalates and sulphonamide) it is possible to detect the presence of a blend of plasticisers. If a quantification of the blend composition is required, though, this is usually easier to achieve by HPLC then IR. The TGA technique can usually provide good quantifications of plasticiser contents, particularly with synthetic species such as phthalates. Some of the mineral oils and plasticisers that have higher molecular weights (e.g., so called polymerised plasticisers) can give problems, as the weight loss event due to their volatilisation can merge with the pyrolysis weight loss event of the polymer. As mentioned in the previous section, polymers that lose small molecules by heat degradation (e.g., HCl lost by polychloroprene) give more complicated TGA traces and will require a solvent extraction step to determine their plasticiser level.

Figure 8 IR spectrum of di(2-ethylhexyl) phthalate

Figure 9 IR spectrum of triphenyl phosphate

18

Rubber Analysis – Polymers, Compounds and Products

4.3 Determination of Fillers

A TGA trace of a nitrile rubber formulation showing the quantification of carbonaceous residue and carbon black is shown in Figure 10.

4.3.1 Carbon Black (see also Section 5) TGA is an excellent technique for the quantification of carbon black in rubber compounds. Only small samples are required and the results obtained have a reasonable degree of accuracy as shown by the data generated by Pautrat and co-workers (349). Although TGA is useful for quantifying the amount of carbon black, it is very limited in being able to distinguish between the different types of carbon black. This is because there is no clear relationship between particle size/particle structure and oxidation temperature maxima. There is, however, a loose relationship, in that the higher surface areas of the small particle size blacks (e.g., SAF) give lower oxidation temperature maxima than the larger particle size blacks. A number of workers have used the T15 figure to investigate these effects. T15 is the time taken for 15% of the weight of the carbon black to oxidise. A loose relationship was found but no absolute correlation. The fact that a number of rubbers (e.g., halogenated, nitrile and polyurethane) produce carbonaceous residues during the nitrogen atmosphere region has already been mentioned in Section 4.1, and care must be taken to ensure that these do not affect the quantification of carbon black in the air atmosphere region. Use of a high resolution TGA instrument will assist in this as it will improve the separation of the two weight loss events.

4.3.2 Inorganic Fillers TGA is also convenient for the quantification of inorganic fillers such as barytes, silica and silicates. The limitation of the technique is that the total inorganic content of the rubber is obtained, with no indication of the relative proportion if a blend of fillers is present. Since most rubber compounds contain zinc oxide as part of the cure system (sulfur systems) or as an acid acceptor (peroxide cure systems), it is common practice to complement the TGA data with a least a semiquantitative elemental technique, such as XRF, in order to obtain qualitative as well as quantitative data. A useful exception to this rule is where the compound contains calcium carbonate (a relatively common diluent filler), in which case the carbonate will undergo quantitative degradation at around 680-700 °C into carbon dioxide and calcium oxide (which remains as a residue). It is therefore possible to quantify the amount of calcium carbonate in the sample from the carbon dioxide weight loss (which will represent 44% of the carbonate by mass) and the remaining quantity of residue will indicate if any other inorganics are present. The trend towards these analytical techniques being incorporated into international standards has continued with a recent standard having been published (ISO 9924-1 (2000)) which describes the use of TGA for the determination of the composition of butadiene,

Table 2 TGA quantification of carbon black added to rubbers Black type HAF

SRF

MT

Rubber type

Quantity of black added Quantity of black found (mg) (mg)

EPDM

30.4

31.3

IIR

28.2

30.0

NR

31.5

33.7

SBR

30.0

31.0

EPDM

41.7

43.4

IIR

33.2

34.4

NR

31.5

33.0

EPDM

48.5

51.6

IIR

34.0

35.5

NR

31.5

33.5

19

Rubber Analysis – Polymers, Compounds and Products

Figure 10 TGA trace of a nitrile rubber

ethylene-propylene, butyl, isoprene and SBR rubbers. Further parts of the standard will address other rubber types. The other technique commonly used for the quantification and isolation of inorganics is furnace ashing. This method is described in ISO 247 (1990). This method details two procedures. The first, dry ashing may be unsuitable for rubbers containing halogens (due to the loss of volatile halides, such as zinc chloride formed by the reaction of zinc oxide with the hydrogen chloride liberated from the polymer). The second, acid ashing, is not recommended for raw rubbery polymers. There are two temperature options in the standard: 550 °C and 950 °C. Care has to be taken with the higher one if no knowledge of the types of inorganics present is available. With this in mind 550 °C is the more common ashing temperature used. Once the ash has been obtained, qualitative information on the inorganic species present can be obtained by IR spectroscopy (liquid paraffin mull technique), XRF, or, where the quantification of specific species is required, ICP. Some of the principal diagnostic IR absorption bands for inorganic fillers are as follows:

20

Silica

Broad band at 950-1330 cm which peaks at 1050-1100 cm

Silicates

Broad band at 850-1300 cm which peaks at 950-1100 cm

Calcium carbonate

1420, 870 and 710 cm

Barium sulfate

1080 and 610 cm

Where it is thought desirable to analyse relatively large samples (e.g., 2-5 g) a tube furnace can be used along with a similar set of operating conditions to the TGA. Values for total organics, total carbonaceous material and total inorganics can be obtained. The technique has the disadvantage over TGA in that qualitative information, such as the detection of a blend of carbon blacks, and quantitative information, such as the amount of carbonaceous residue from the polymer, cannot be obtained.

5 Carbon Black Carbon black is by far the most commonly used filler for rubber compounds and has been in constant use in formulations since just before the First World War. Although carbon black can be added to rubber

Rubber Analysis – Polymers, Compounds and Products

compounds to cheapen them by reducing the proportion of the more expensive polymer component (e.g., in highly ‘extended’ EP compounds), it is more often added to improve the physical properties (e.g., tensile strength and tear strength) of a rubber compound, something which few other filler materials can do. In common with other fillers, it will also increase the hardness and viscosity of a compound. Determination of carbon black is described in Section 4.3. Historically there have been three main types of carbon black, designated by reference to the manufacturing technique used to produce them from oil: •

Furnace black

•

Thermal black

•

Channel black

The first of these is the most common type (95% of the market), is available in a large range of grades (more than 20) and used in a wide range of rubber types. The second type is available in only a few grades and tends to be used in a limited range of compounds (e.g., fluorocarbon rubbers). The third type is rarely seen, although it has some specific uses.

5.1 Analysis of Free Carbon Black

5.1.1 Particulate and Aggregate Size The most popular technique for the examination of the particles of carbon blacks uses the scanning electron microscope (SEM). There have, however, been a number of other techniques used, e.g., X-ray diffraction, transmission electron microscopy (TEM), atomic force microscopy and scanning tunneling microscopy and these feature in a review of the subject (240). These last two techniques can be used to examine the surface structure of carbon black (275). In addition to the examination of the individual particles, TEM is a useful tool for the recording of particle aggregates (a.6).

5.1.2 Total Surface Area The total surface area of a carbon black sample, that is, the area that can be accessed by rubber molecules and that within pores and between particles, provides an indication of particle size. There are three main methods for the determination of total surface area.

5.1.2.1 BET Method (Nitrogen Adsorption) Two specialist carbon blacks exist. Lampblacks which have been developed by the Chinese for ink and lacquer formulations; and acetylene black which is conductive and used in conducting rubber compounds. Carbon black is an extremely pure form of carbon which consists of very small, mostly spherical particles which fuse together in clusters referred to as aggregates. The aggregates themselves group together as agglomerates which break up during the mixing process. The aggregates tend to remain intact in the rubber matrix and the type of aggregate defines the structure of a carbon black; the higher the structure the greater the number of particles in an aggregate. The greater the number of particles in an aggregate, the larger will be the volume within it that is not accessible to rubber molecules. The properties that define a particular carbon black are as follows: •

Sphere size

•

Structure (aggregate size and shape)

•

Total surface area

•

Surface area available to rubber molecules.

Named after Brunauer and co-workers, who developed it in 1938, this method is described in ISO 4652 and is carried out using a Ni-Count-1 instrument. It also features in ASTM D 3037 (1978) where there are four accepted procedures, one of which uses the Ni-Count-1.

5.1.2.2 Iodine Adsorption This method uses simple laboratory equipment and produces results which correlate well with the nitrogen adsorption method. The procedure to be followed is described in ISO 1304 (ASTM D1510). Reinforcing grades of black have iodine adsorption numbers typically in the 70-160 mg/g range whilst semi-reinforcing grades are in the 30-45 mg/g range.

5.1.2.3 Cetyltrimethylammonium Bromide (CTAB) Adsorption This method, where a large molecule is used as an adsorption species, is described by Lamond and Gillingham (a.7). It is thought to be more accurate than the other two methods because it is less influenced by the chemical nature of blacks and is less sensitive to particle porosity.

21

Rubber Analysis – Polymers, Compounds and Products

A similar procedure to that suggested by Lamond and Gillingham is presented in ASTM D 3765.

5.2.1.1 Digestion of the Matrix Followed by Filtration

Reinforcing grades of carbon black have CTAB values in the 80-140 m2/g range, whilst semi-reinforcing grades are in the range 30-45 m2/g.

In this method the polymer in the rubber vulcanisate is destroyed and solubilised by a chemical such as a strong acid (e.g., nitric acid) in the presence of an organic solvent (e.g., nitrobenzene) and heat. The carbon black is then recovered by filtering the mixture. The drawback in the method is the difficulty of achieving a sufficient degree of degradation, especially with the more chemical resistant rubbers.

5.1.3 External Surface Area This test enables a measurement of the amount of structure in a carbon black to be established. The dibutyl phthalate (DBP) test is described in ASTM D 2414 and involves adding the phthalate from a burette into a weighed portion of carbon black which is stirred constantly. As the DBP is added, the carbon black powder changes to a semi-liquid mass with an increase in torque. At the limit of DBP absorption the torque peaks. The result is expressed as ml of DBP per 100 g of carbon black. Low structure blacks have values in the range 60-80 ml/100 g, with high structure types in excess of 120 ml/100 g.

5.2.1.2 Isolation by Non-Oxidative Pyrolysis In a non-oxidising atmosphere heating of the rubber compound to a temperature around 500 °C results in the pyrolysis and loss of the polymer fraction as volatile products. This leaves a residue comprised of carbon black and inorganic species. The carbon black is then prepared by an acid wash, a water wash and then low temperature drying (around 105 °C), with final light grinding to break up any aggregates.

5.1.4 Miscellaneous Analytical Techniques 5.2.2 Total Surface Area Tests on Recovered Black

There are a number of techniques that have been used to characterise carbon blacks (Table 3).

5.2 Analysis of Carbon Black in Rubber Vulcanisates

All three methods described in Section 5.1.2 have been applied to carbon black that has been recovered from vulcanisates.

5.2.1 Isolation of Carbon Black from a Vulcanisate

The results obtained suggest that with the BET method the type of rubber that the black has been recovered from can influence the data, Table 4.

Historically, there are two main routes for the recovery of carbon black from rubber vulcanisates.

The results obtained using the CTAB method were more independent of polymer type, see Table 5.

Table 3 Techniques used to characterise carbon blacks Technique

Application

Reference

Inverse gas chromatography (IGC) Surface energies and thermodynamic parameters

Wang, Wolff and Donnet (a.8) Wang and Wolff (325)

Neutron scattering

Particle structure

Hjelm and co-workers (a.9)

Raman spectroscopy and X-ray scattering

Particle microstructure

Gruber, Zerda and Gerspacher (a.10, a.11) Gerspacher and Lasinger (333)

GC-MS, SIMS, XPS and IGC

Surface chemistry

Ayala and co-workers (a.12)

22

Rubber Analysis – Polymers, Compounds and Products

Table 4 Total surface area (m2/g) of carbon blacks determined by the BET method Black type

Original black

Recovered from NR

Recovered from SBR

Recovered from SBR/BR

N110

144.6

132.5

127.5

123.9

N220

124.2

124.3

112.9

110.0

N330

82.9

86.4

78.2

74.5

Table 5 Total surface area (m2/g) of carbon blacks determined by the CTAB method Black type

Original black

Recovered from NR

Recovered from SBR

Recovered from SBR/BR

N110

103.9

98.2

99.1

100.1

N220

95.9

96.1

92.0

91.0

N330

65.0

71.5

62.0

68.9

5.2.3 External Surface Area Test on Recovered Black The DBP test has been carried out on black recovered from vulcanised rubber using the preferred pyrolysis route and, as with the total surface area tests, reasonable results have been obtained enabling the type of black used to be determined.

5.2.4 Quantification of Carbon Black in Rubber Vulcanisates It is possible to quantify the amount of black in a vulcanisate by using a pyrolysis approach analogous to that described in Section 5.2.1.2. A final stage is added where the sample, having been weighed after the non-oxidative pyrolysis procedure, is heated in an oxidising atmosphere (either air or oxygen) to oxidise the carbon black to carbon dioxide. The final, inorganic residue is weighed and the amount of black in the sample calculated using the following equation: Amount of carbon black (%) =

A modern, automated technique involves the use of the thermogravimetric analyser (TGA, Section 2.5.3). This instrument can determine the amount of carbon black in a sample, along with the amount of the other principal ingredients (e.g., plasticiser and polymer), in one seamless operation with automatic gas switching and data collection. Compared with the tube furnace, small samples are analysed (1-10 mg), but this has the advantage that the technique can be used on things such as contaminants, or in a virtually non-destructive way. A more in depth discussion of the determination and analysis of carbon black within rubber compounds is given in Section 4.3.

5.2.5 Dispersion of Carbon Black Within Rubber Products To achieve the optimum properties it is important that the carbon black within a rubber is uniformly dispersed. There are a number of tests that have been developed to assess the degree of dispersion:

A-B x 100 Original weight

5.2.5.1 Cabot Dispersion Test where A = Residue after non-oxidative pyrolysis stage B = Final residue The above experiment can be carried out in a tube furnace and has the advantage that relatively large (e.g., 1-2 g) samples can be used.

This test (a.13) involves the cold stage microtoming of thin (approximately 2 μm thick) sections from the rubber, which are then immersed in xylene and examined between glass slides using a light transmission microscope fitted with a Cabot graticule.

23

Rubber Analysis – Polymers, Compounds and Products

The degree of dispersion is graded using a Cabot Dispersion Classification Chart.

5.2.5.2 Cut Surface and Torn Surface Methods The surfaces of the rubber are viewed using incident illumination, hence avoiding the need to prepare microtome sections, and a degree of automation is provided by equipment such as the Optigrade Dispergrader. The torn surface method is described by Sweitzer and co-workers (a.14) and Stumpe and Railsback (a.15) and is, in effect, a method for the determination of the agglomeration of carbon black within the sample. Grading is again possible and a scale of 1 (very poor dispersion) to 10 (excellent dispersion) is used.

5.2.5.3 Transmission Electron Microscopy Very thin sections are required (less than 100 nm) and the small area examined makes it possible to evaluate the dispersion of black within phases of polymer blends. Care has to be taken though that the small area analysed does not lead to unrepresentative results. A detailed description of the microscopy of rubber samples is provided by Kruse (352).

6 Determination of Antidegradants in a Rubber Compound In common with other polymer systems, to maintain the physical properties imparted to a rubber compound by the judicious choice of polymer type, filler, plasticiser and cure system, stabilisers need to be added to stop, or at least retard, degradation by a number of agencies (e.g., heat and UV light). The use of an initial solvent extraction step is common in the analysis of a rubber matrix for antidegradants, as these species may not be volatile enough to be removed by heating the sample. In some cases (e.g., butylated hydroxy toluene and IPPD), heating a sample liberates enough of the species to enable an identification to be made using GC-MS; however quantification will usually require extraction by a solvent (to as near 100% efficiency as possible). Analysis of the extract can then be carried out by HPLC, UV spectroscopy, or GC if the species is heat

24

stable and sufficiently volatile. Relatively nonspecific solvents (i.e., having mid-range solubility parameters) such as chloroform and acetone are good extracting solvents. If a high proportion of oligomeric material is present in the extract (sometimes a problem with unvulcanised rubber compounds), it can be necessary to add a precipitating solvent (e.g., methanol or heptane) to prevent this from interfering with the chromatography. If the type of organic antidegradant in a compound is completely unknown, analysis of the solvent extract by GC-MS is an excellent method for identification. Once the identification has been achieved, quantification can be carried out using a preferred method and a validated procedure if available. Where the antidegradant is not volatile enough to be identified using a GC based technique, direct probe mass spectrometry can be used and the antidegradant identified by reference to its molecular ion and a database of molecular weights. This technique can be carried out on samples in the as received state as well as sample extracts.

6.1 UV Stabilisers The widespread use of carbon black in rubber compounds gives the additional advantage of stabilisation against UV light, the filler preferentially absorbing the energy and so protecting the polymer. The quantification of carbon black (usually regarded correctly as a filler) is described in Section 4.3. The white pigment titanium dioxide also provides protection against UV light and can be incorporated into non-black articles. The amount of titanium dioxide in a rubber can be determined after acid digestion of the matrix by the use of an elemental technique such as AAS/ICP. Benzotriazoles and hindered amines can be used as UV stabilisers. The UV absorbing qualities of these species can be employed for their detection and quantification by UV spectroscopic analysis of solvent extracts of the rubber sample.

6.2 Antioxidants The international standard ISO 11089 (1997) deals with the determination of N-phenyl-β-naphthylamine and poly-2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) as

Rubber Analysis – Polymers, Compounds and Products

well as two generic types of antiozonant (see Section 6.3). This method has been successfully tested on polychlorobutadiene (CR), NBR and SBR rubbers and involves an initial extraction step using a 2:1 mixture of isopropanol and dichloromethane. The extract obtained is then analysed by reverse phase HPLC using a mixed solvent programme with UV detection. In addition to the above, HPLC has been widely used by analysts for the determination of antioxidants in rubbers and two reviews have been provided by Sidwell (344) and Sullivan and co-workers (350). A useful HPLC method, which is a modification of a method developed by an antidegradant manufacturer, can be used on rubbers for the detection and quantification of a wide range (20 species) of antidegradants. The sample is cryogenically ground up into a fine powder and then extracted with diethyl ether for 30 minutes with ultrasonic agitation. The extract is then analysed by HPLC using the following conditions: Injection volume

25 μl

HPLC column

Aqua 5 C18 ODS reverse phase column 150 mm x 3.0 mm (or similar)

Mobile phase

A = 75/25 Methanol/water B = 50/50 Ethyl acetate/ acetonitrile

Gradient

Time Initial After 25 mins

%A %B 90 10 0 100

Flow rate

2.0 ml/min

Detection

UV detector set at 270 nm

Temperature

40 °C

The following antioxidants are examples of those that can be determined using this technique: Irganox 1010, Irganox 1098, Irganox 1076, Irganox 1330 and butylated hydroxy toluene. The wide applicability of this method is due to the mobile phase mixture. The capability of HPLC has been greatly extended by the commercialisation of affordable liquid chromatographymass spectroscopy (LC-MS) instruments. The mass selective detector enables unknown samples to be analysed and the antioxidants present to be identified. The LC-MS technique therefore compliments GC-MS and, with it, enables the complete molecular weight/volatility range to be covered.

TLC is comparatively easy and cheap to use and it is both quick and accurate for the identification of antioxidants in rubber extracts. Irrespective of the complexity of the extract composition and the amount used, this method can be used to give a sharp separation for identification purposes. Distinctive Rf values and colours can be seen for each antioxidant depending on the stationary phase, the developing solvent used and the detection agent (a.16, a.17). Normal silica gel has proved effective as a stationary phase, as have others such as alumina starch, gypsumsilica gel and starch-silica gel, and where identification is difficult because of the interferences of co-extracted compounding ingredients, two dimensional development methods using two types of solvent system have been employed (a.18). The TLC technique for antidegradants is also described in ASTM D 3156 and ISO 4645.2 (1984). The rubber extract is taken up in dichloromethane and then a spot of this solution developed in the developing tank using the nominated solvent. TLC, in addition to being used for identification purposes, can be used in a semiquantitative way; the logarithm of the spot area being proportional to the quantity of the analyte in the spot, and this value being compared to spots containing standard amounts of the analyte. The complexity of rubber extracts usually limits the accuracy of the quantifications obtained. Gas chromatography has been used for the analysis of phenolic and amine type antioxidants. Antioxidants which have high boiling points cannot be directly analysed by GC but they can be analysed as derivatives such as acetates, trifluoroacetates, trimethyl silylethers, methyl ethers, etc. Trimethyl silane based antioxidants, for example, give good separations on standard silicone based columns (a.19).

6.3 Antiozonants The only organic compounds which have shown themselves to be very effective in the protection of diene rubbers against chain scission by ozone (via the cleavage of the carbon-carbon double bond) are paraphenylenediamine compounds. In addition to the analysis of antioxidants (see above), the standard ISO 11089 (1997) can be used to determine N-alkyl-N´-phenyl-p-phenylenediamines (e.g., IPPD and 6PPD) and N-aryl-N´-aryl-p-phenylenediamines (e.g., DPPD) by HPLC.

25

Rubber Analysis – Polymers, Compounds and Products

The HPLC chromatogram of a methanol extract from a polychloroprene compound is shown in Figure 11. From the data in Figure 11 it is possible to identify and quantify diaryl-p-phenylene diamine antiozonants in the sample. A microcrystalline polyethylene wax is often added to a rubber formulation along with a para-phenylene type antiozonant. These types of wax have a limited solubility in the rubber matrix and so bloom to the surface. In doing so they help the antioxidant migrate to the surface where it is needed to function, but, more importantly, they provide a physical barrier to ozone. This approach is most successful in static applications, but breaks down if the rubber is stressed as the protective film will be ruptured. The fact that these waxes bloom to the surface can be used for their detection by surface analysis techniques such as infrared microspectrometry. Unfortunately, these waxes are only added at relatively low dosages to the compounds (e.g., 2-5 pphr) and so their detection by direct matrix analysis techniques (e.g., DSC, pyrolysis IR) is unlikely to succeed, and their relatively high molecular weight and relatively poor solubility makes isolation by solvent extraction difficult.

TLC can be used for the analysis of para-phenylene diamines. The best results for the isolation and identification from extracts are obtained using isopropanol/chlorobenzene/water/25% aqueous ammonia (52:33:10:5) as the developing solvent, and diazotised 4-amino-benzene sulfuric acid or 3,5dibromo-p-benzoquinonechlorimine as the colour forming reagent.

7 Determination of Cure System Additives and Their Breakdown Products This section looks at the analysis of rubbers to obtain information on their cure systems. There are two principal types of cure system used in rubber products: sulfur or peroxide. Where either of the systems could have been used (e.g., EPDM rubbers) it is usually possible to differentiate between them by carrying out a sulfur determination. Although additives such as carbon black will contribute to the overall sulfur level in a rubber compound, a low result (e.g., <0.3% w/w) is usually indicative of a peroxide cure system. Techniques to quantify the amount of sulfur in a rubber are discussed in Sections 2.1 and 2.2. In common with most other aspects of rubber analysis, there can be complications, and it is possible for technologists to add elemental sulfur into a rubber as a peroxide cure co-agent. Therefore, a relatively high sulfur level cannot always be taken to indicate a sulfur type cure system and further work (e.g., GC-MS) needs to be carried out. The identification of peroxide co-agents such as triallyl cyanurate (TAC) are covered in Section 8.4. The fact that some sulfur cure system accelerators (e.g., TMTD) produce nitrosamines during the curing process has given cause for concern for a number of years. Because of the potential health and safety concerns, a number of studies have been carried out on these species. Analysis of rubber compounds for nitrosamines usually takes the form of extraction followed by GC analysis using a specific detector (e.g., electrolytic conductivity or thermal electron analyser). A review of the entire subject of nitrosamines in rubber is given in a Rapra publication (a.20).

7.1 Analysis of Uncured Samples

Figure 11 HPLC chromatogram of the methanol extract from a polychloroprene compound

26

In the case of failure and deformulation work it is usually only the cured rubber which is available for analysis, since the sample will have originated from a product.

Rubber Analysis – Polymers, Compounds and Products

However, there are examples, and quality control work is one, where the uncured sample will be available. This will provide the opportunity to look for unreacted accelerators and cure agents such as peroxides. Particular care has to be taken because these chemicals are, by their nature, thermally labile and reactive. It is not possible therefore to use hot solvent extraction and elevated temperature analysis techniques such as GCMS, since these will bring about the same types of reactions that occur during cure. Rather, cold extraction is used and an ambient temperature separation and identification technique such as TLC or HPLC. It should also be borne in mind that, even at ambient temperature, the choice of extraction solvent can be important. The use of acetone can cause thiuram disulphide accelerators (e.g., TMTD) to decompose to dithiocarbamates. For this reason, the use of solvents such as methanol, 2propanol and dichloromethane is preferred. Gross and Strauss (347) have described the use of HPLC for the analysis of accelerators. There are many reviews concerning the use of TLC, two useful ones being McSweeny (a.21) and Hummel and Scholl (339). In recent years advances in technology have reduced the price and hence increased the accessibility of HPLCmass spectrometer combinations (commonly referred to as LC-MS). These instruments can be used to provide both molecular ion (parent ion) information on the LC species peaks as well as being able to generate 70 electron volt fragmentation spectra which are analogous to those generated by GC-MS instruments. This latter mode of operation is very convenient, since it is possible to use existing mass spectral databases and not rely solely on molecular ion values, which may not be unique and cause problems in the identification of unknowns. This development is very welcome and will widen the molecular weight range for which mass spectral data can be routinely generated. Once these systems are widely available it is to be expected that they will replace older techniques such as TLC.

7.2 Analysis of Cured Samples This is the more usual state of affairs. It is necessary to have a certain amount of knowledge on the types of species that are formed during vulcanisation reactions if success in identifying a cure system is to be forthcoming. The most useful generally available technique for this type of work is GC-MS. There are two possible modes of sample introduction: solution injection and dynamic/ static headspace. In the case of the former a useful method of sample preparation involves cryogenic

grinding of 0.3 g of the sample, followed by extraction using 2 ml of diethyl ether in an ultrasonic bath for 30 minutes. The resulting extract is then analysed, for example, under the following conditions: Instrument

Hewlett Packard 6890/ 5973 GC-MSD

Carrier

Helium @ 2.0 ml/min constant flow

Injection mode

1 μl splitless (0.75 min; 50 ml/min)

Injection temperature

320 °C

Column type

RTX5-MS 30 m x 0.25 mm, 0.25 μm film thickness

Column temperature

40 °C for 5 min, 20 °C/min up to 300 °C held for 12 min

MS settings

20 to 620 Daltons scanned every 0.33 sec

The diethyl ether is relatively non-selective and this method enables the large majority of the diagnostic species of interest to be detected. Other non-cure system species such as antidegradants and process aids will also be identified. The main drawback with this approach is that volatile diagnostic compounds such as low molecular weight amines (e.g., dimethylamine) can be masked by the large solvent peak at the start of the chromatogram. The headspace techniques provide a means of identifying the largest range of cure system breakdown products, particularly in conjunction with cryogenic cooling of the GC oven to improve resolution of the early eluters. In this approach, a relatively small amount of sample (e.g., 3 mg) is heated in the oven of a dynamic desorption unit and the volatiles produced are collected in a cryogenically cooled Tenax filled trap. The experimental conditions are, typically, as follows: Dynamic Headspace Instrument

Perkin Elmer ATD 400

Desorption temperature

150 °C for 10 min

Desorption flow

Helium @ 20 ml/min

Trap collection temperature

–30 °C

Trap injection temperature

250 °C

Trap outlet split flow

9 ml/min

Trap inlet split flow

off

Split

10:1

27

Rubber Analysis – Polymers, Compounds and Products

GC-MS

of these are common to more than one cure system species. This is demonstrated in Table 6 below.

The conditions used are the same as for the diethyl ether method with the exception of the following: GC column temperature

Carrier

–30 °C to 50 °C at 5 °C/ min, following by 20 °C/ min to 300 °C and then held at 300 °C for 12 min Helium @ 10.5 psi

For either analytical approach, identification of the diagnostic cure system breakdown species is by reference to mass spectral libraries, such as those produced by the National Institute of Standards and Technology (USA) (NIST), the Royal Society of Chemistry (RSC), Wiley/NBS (a.22) and the USA Environmental Protection Agency (EPA)/National Institute of Health (NIH). The mass spectra of the majority of species of interest are in these libraries and so, providing that the knowledge to reconstruct cure systems is available, successful attempts can be made to interpret the results.

This type of diagnostic fragment data is included in the book by Willoughby (319). The new LC-MS systems mentioned in Section 7.1 will also assist in the analysis of vulcanised rubber, since the types of species being investigated will be amenable to reverse phase HPLC.

8 Determination of Miscellaneous Compound Additives

8.1 Blowing Agents There are two main types of blowing agent used with polymer systems in general, physical and chemical. 1) Chemical

One problem associated with this task is that most accelerators and curing agents, such as peroxides, breakdown to give more than one product and a number

Chemical compounds (principally organic) that undergo chemical decomposition at the vulcanisation temperature to form a gaseous species

Table 6 Diagnostic species associated with different cure systems

28

Sulfur cure system

Diagnostic species

MBS/MOR

Benzothiazole Morpholine

Sulfrasan R

Morpholine

MBT

Benzothiazole

MBTS

Benzothiazole

TMTD

Dimethylamine Tetramethyl thiourea Dimethyl formamide

ZMDC

Dimethyl formamide Dimethylamine

Peroxide curative

Diagnostic species

Perkadox 14/40

Tertiary butanol 1,3 Di-(1,1-dimethylmethanol) benzene methanol

Tert-butyl cumyl peroxide

1,1-Dimethyl benzene methanol Acetophenone Tertiary butanol

Dicumyl peroxide

1,1-Dimethyl benzene methanol Acetophenone

Rubber Analysis – Polymers, Compounds and Products

(e.g., nitrogen) which will create the cellular structure. Examples include: azo compounds, nitroso compounds, sulfonyl hydrazide compounds and sodium bicarbonate. 2) Physical

Low boiling point organic compounds (e.g., dichloromethane or pentane) which volatilise at the processing temperature to create a cellular structure.

With rubbers, by far the most widely used types are chemical blowing agents, the vast majority of which decompose to produce nitrogen. The reactivity of these compounds can make analysis difficult even if the rubber sample is uncured (e.g., they will decompose in the injection port of a GC-MS instrument), and the approach that is employed to identify cure system additives is often used, indirect identification by the determination of breakdown fragments. The GC-MS instrument is the best choice for this and a library of typical breakdown fragments is required. Quantification of blowing agents in an uncured product is very difficult as their polarity and reactivity (e.g., hydrogen bonding reactions and thermal instability) can cause problems in their isolation from the compound and subsequent analysis. In terms of reverse engineering, this is unlikely to be required since the product will invariably be already blown. For laboratories that carry out quality control, other properties such as density and expansion ratios can be used to determine compound loadings. Where it is suspected that a physical type blowing agent has been used to produce a foam, is it possible to use headspace GC-MS to identify it. Even in the blown state, the high sensitivity of the technique enables an assignment to be made from the small amount of residual blowing agent that will be present. It is uncommon for these types of agents to be used as the curing/processing temperatures of standard rubbers are normally too high to give controlled blowing. They tend to be used in amorphous plastics (e.g., polystyrene) which have relatively low (around 100 °C) glass transition temperatures. There is some scope, therefore, for their use in thermoplastic rubbers.

The amount and type of organic flame retardant present in a rubber compound can be determined in an analogous way to the plasticiser (Section 4.2), since this type of flame retardant is usually similar in molecular weight and polarity and, hence, extractability. Once the type of organic flame retardant has been determined by IR spectroscopy, an accurate quantification can be obtained by carrying out an elemental analysis for the halogen (or other relevant element, e.g., phosphorus) on the unextracted sample. The extract value itself will rarely provide a meaningful quantification as other species, particularly any process aid/ plasticiser, will contribute to it as well. In some instances (e.g., organophosphates), it may be possible to use an HPLC analysis of the extract to quantify the flame retardant. GC based techniques can also be used in some cases, but bromide types present problems for these techniques, because of their relatively high molecular weights (> 900). Care must be taken over the quantification of inorganic flame retardants, since some of them (e.g., antimony trioxide) can react with any organic flame retardant present, or break down to produce volatile products (e.g., hydrated alumina), under quantitative ashing conditions, and during analysis by thermal techniques such as TGA. A good initial approach is a semi-quantitative elemental analysis by XRF, to see which types are present. Accurate quantifications can then be obtained by precise elemental determinations. If it is known that hydrated alumina is present in the sample, it is possible to quantify this reasonably well using TGA, by making use of the water loss data. Hydrated alumina loses close to 35% of its weight when it is heated to 550 °C in a TGA experiment.

8.3 Process Aids

8.3.1 Plasticisers and Oils The addition of hydrocarbon oil or a synthetic plasticiser (e.g., DOP) into a compound will improve its processability, in addition to changing a wide range of physical properties. The techniques used to identify and quantify these types of process aid are described in Section 4.2.

8.2 Flame Retardants

8.3.2 Factice

There are two main categories of flame retardant: organic and inorganic.

This is sulfur crosslinked vegetable oil and so a relatively high sulfur content will give a good indication as to its presence.

29

Rubber Analysis – Polymers, Compounds and Products

8.3.3 Resins High styrene resins are thermoplastic polymers of styrene and butadiene and are used to modify the hardness of rubber compounds. They are used in preference to high levels of carbon black as they do not increase the processing viscosity to such a degree. The high level of styrene (up to 85%) makes them easy to detect by looking for the above ambient glass transition by DMTA/thermal mechanical analysis (TMA). The DMTA trace of an SBR rubber containing a high styrene resin is shown in Figure 12. The Tg for the rubber (at ~ –20 °C) and the Tg for the resin (at ~ +50 °C) are clearly visible. Pyrolysis GCMS is also an option, looking for characteristic monomer species. This will obviously be a problem if the resin is in an SBR rubber matrix. Coumarone resins are manufactured by the polymerisation of styrene, coumarone and indene and are used as tackifiers and plasticisers. Varying the polymerisation conditions leads to a range of resins of melting points in the range 65-110 °C. If sufficient resin is present in a sample, the melting point can be detected by DSC. Pyrolysis GC-MS can also be used to detect the presence of these resins in a compound. Thermosetting alkyl phenol-formaldehyde resins can be used instead of the high styrene type, giving

excellent flow characteristics in moulding and extrusion. Non-reactive phenolic resins are used as tackifiers instead of coumarone resins. Phenolic fragments can be detected in solvent extracts and pyrograms by GC-MS.

8.3.4 Pine Tar Analysis of the solvent extract of the sample by GCMS will reveal diagnostic species such as pinene, if this additive is present.

8.4 Peroxide Co-Agents Peroxide co-agents such as triallyl cyanurate (TAC) and triallyl isocyanurate (TAIC) can be detected in solvent extracts of either the unvulcanised or vulcanised (enough remains unbound) rubber by GCMS. It is also possible to detect these species by headspace GC-MS as they are reasonable volatile and are thermally stable. There are a number of other specialist additives (e.g., adhesion promoters and tackifiers), but there is insufficient space in a review of this kind to cover these.

Figure 12 DMTA trace for an SBR rubber containing a high styrene resin

30

Rubber Analysis – Polymers, Compounds and Products

9 Cure State Studies It is often necessary to study the cure characteristics of rubber or the cure state of a rubber product. The former occurs during research, development and quality control, and the latter as part of a failure diagnosis investigation. One technique which is particular useful for this type of work is DSC. The curing reaction of a rubber, in common with other types of chemical reactions, is very exothermic and therefore manifests itself strongly in the specific heat plot of the sample. Two advantages of DSC are that only small sample sizes are required (e.g., 5 mg) and no specific sample geometry is necessary. It is possible to use DSC in a number of ways. It can be used to determine the amount of cure system in a rubber. The exotherm obtained is very specific to the rubber matrix and the cure system used, so standards need to be available if quantitative data is to be obtained on an unknown from the joules/gram exotherm value. This technique obviously has uses from a quality control point of view. An example of DSC being used in this way is shown in Figure 13, where the exotherms obtained for a range of peroxide concentrations (0.2 to 3.0 pphr) in a nitrile rubber are displayed.

Small samples can be analysed to depth profile vulcanisates to investigate the degree of cure through a section. The ability of DSC to detect residual unreacted curatives can be used in a more general sense to investigate if a product has been properly cured. In these examples, the exotherm generated can be relatively small and can occur in a similar region to where additives, such as plasticisers and oils, are volatilising (resulting in an endotherm), thus very difficult to detect. It is therefore important to modify the experimental conditions to maximise the sensitivity of the system to the curing exotherm. If possible, larger samples should be used and more importantly, sealed sample pans should be used to stop material volatilising. It is advisable to use sealed pans for all cure studies for this reason. A review of the use of DSC to study sulfur and peroxide vulcanisation processes is given by Brazier (a.23). Another technique which can be used in investigating the degree of cure of a rubber product is DMTA. It suffers from two drawbacks when compared to the DSC technique: a certain sample size (normally 2 cm x 1 cm x 1 mm) is required and it is less sensitive, relying on the effect that crosslink density has on the glass transition temperature of the rubber compound. This is monitored by reference to the peak height of the tan delta plot in the DMTA thermogram. As the degree of cure increases, the height of the tan delta peak decreases accordingly as is shown in the table below:

Table 7 Decrease in tan delta peak height of the DMTA thermogram of different rubbers on curing Rubber type

% Decrease in tan delta peak height *

Natural rubber

15%

Polyisoprene rubber

76%

Butadiene rubber

64%

*Optimum cure compared to unvulcanised compound

Figure 13 DSC cure exotherms for nitrile rubber containing different peroxide levels

It is also possible to use TMA to determine the degree of cure of a rubber. The sample is heated from ambient to 200 °C and the small dimensional change that occurs is monitored. The dimensional change observed increases as the cure state increases. For example, a

31

Rubber Analysis – Polymers, Compounds and Products

degree of cure of 50% (based on rheometer readings) might give a change of around 20 μm, which increased to around 40 μm for a fully cured sample. Providing that reference data for a particular system is available, the technique can be used to investigate the cure state of an unknown sample. Andersson and co-workers (338) have used pyrolysis GC to study the sulfur bridges in filled NR vulcanisates. The GC was fitted with a sulfur selective flame photometric detector and the main pyrolysis products detected were carbon disulfide and thiophenes. Two NR formulations were analysed, one cured with sulfur and CBS, and the other with the sulfur donor TMTD. The yields of the pyrolysis products were found to be different for the two rubbers and to vary with the cure time in both cases. A comprehensive review of the use of chemical analysis techniques to investigate the cure of rubbers and other polymers systems has been published by Rapra (322).

•

Filler content and type(s)

•

Carbon black content

•

Plasticiser content and type(s)

10.1 Initial Suite of Tests These are designed to enable as much compositional information as possible to be obtained in the most cost effective way. The following techniques were employed.

10.1.1 Quantitative Solvent Extraction A part of the sample was milled on a two roll laboratory mill and then extracted with methanol for 16 hours. At the end of the extraction period the extract was dried at 105 °C for 30 minutes and then weighed. This procedure was carried out in duplicate and both the extract and extracted portion retained for further work.

10 Reverse Engineering and Product Deformulation One of the most frequent tasks asked of a rubber analyst is to deformulate a rubber compound. One of the reasons for this is to ensure that a correct formulation was used in the original specification as the component has subsequently failed in service. The other main reason is a commercial one, and it is to enable a manufacturer to investigate the products in a particular market to see if there is scope to compete. In order to illustrate how the various analytical techniques that have been discussed in this review can be combined to achieve a deformulation, a reasonably complex example will be worked through. It should be remembered that there is considerable latitude available to the analyst in the approach to this type of work and that one single ‘correct’ way does not exist. This example is a highly flame retardant elastomer compound used to produce a foam insulating product for use in the cable industry.

10.1.2 Ash Content The ash content of the sample was determined using the method described in ISO 247. This procedure was carried out in duplicate.

10.1.3 Thermogravimetric Analysis A part of the sample (approximately 10 mg) was analysed by TGA using the following programme: Initially the sample was heated from ambient to 550 °C in a nitrogen atmosphere. When a constant weight had been obtained, the temperature was reduced to 300 °C, the atmosphere changed to air and then the temperature raised to 950 °C. Weight loss and derivative weight loss curves were plotted throughout. The heating rate at each stage was 20 °C/min and the flow rate of nitrogen and air 50 ml/min.

The objective of the analysis was to obtain information on the following:

10.1.4 Infrared Spectroscopy •

Polymer content and type(s)

•

Flame retardant content and type(s)

32

The following analytical procedures were carried out using IR:

Rubber Analysis – Polymers, Compounds and Products

a) An IR was recorded of the sample extract prepared in 10.1.1 b) An IR was recorded of the methanol extracted portion of the sample prepared in 10.1.1 c) An IR was recorded of a liquid paraffin mull of the ash prepared in 10.1.2.

10.1.5 X-Ray Fluorescence Spectroscopy A semi-quantitative elemental scan was carried out by XRF on the sample as received, the methanol extracted portion of the sample and the sample ash.

10.1.6 Gas Chromatography-Mass Spectroscopy A part of the sample was qualitatively extracted with chloroform for 16 hours and then the concentrated extract analysed by GC-MS under the following conditions: Injection

1 μl split 30:1

Injection temperature

320 °C

GC column

SGE BPX5 25 m x 0.32 mm, 0.2 μm film

GC column temperature

40 °C for 2 mins, followed by 20 °C/min to 320 °C

Mass spectrometer

Scanning 25 to 400 Daltons every 2 sec

An experiment was also conducted where the sample was heated to 180 °C for 10 minutes in a tube furnace and the volatile species trapped onto an adsorbent packed with Tenax. The Tenax was then transferred to an automated thermal desorption unit and desorbed for 10 minutes at 300 °C. The desorbed species were trapped in a cold trap set at –30 °C and, once the desorption was complete, injected into the GC-MS by rapid heating of the trap to 300 °C. The compounds injected into the GC-MS were then analysed under the same conditions as shown herein.

10.2 Results From the Initial Suite of Tests The methanol extract value of the sample was 34.73% and the IR spectrum (Figure 14) was a composite with evidence for: pentabromodiphenylether (flame retardant) a phosphate ester (flame retardant). The pyrolysate IR spectrum for the extracted portion of the sample (Figure 15) gave data that was consistent for a blend of: nitrile rubber and PVC. The ash content value for the sample was found to be 18.28% and the IR spectrum was a composite (Figure 16) with evidence for:

Figure 14 IR spectrum of a methanol extract of the unknown sample

33

Rubber Analysis – Polymers, Compounds and Products

Figure 15 Pyrolysis IR spectrum of the unknown sample

Figure 16 Liquid paraffin mull IR spectrum of the unknown sample aluminium oxide (from the flame retardant hydrated alumina) metallic oxides. The semi-quantitative elemental XRF data obtained is shown in Table 8. The elemental data confirms the qualitative IR assignments and in addition, shows that two oxides are present in the sample: antimony trioxide (a flame retardant) and zinc oxide (part of the cure system for the nitrile rubber).

34

The TGA trace of the sample was unusually complex due to the additional weight loss events of the PVC (dehydrochlorination, main chain breakdown and additional carbonaceous residue - the nitrile also gives some) and the loss of water of the hydrated alumina. These events meant that it was not possible to obtain accurate quantifications of plasticiser, polymer, carbon black and inorganics. It is therefore only possible to calculate the following (w/w): Plasticiser, organic flame retardants, polymer and lost water 72% Total carbonaceous material (from PVC, nitrile and carbon black pigment) 7% Total inorganics 21%

Rubber Analysis – Polymers, Compounds and Products

Table 8 Semi-quantitative elemental XRF data on the unknown sample Element

As received (%)

Methanol extracted portion (%)

Ash (%)

Si

0.25

0.10

0.10

Ti

<0.01

<0.01

<0.01

Al

23.5

30.0

77.0

Fe

<0.01

<0.01

<0.01

Ca

0.04

0.06

0.15

Mg

0.45

1.10

0.35

K

0.05

<0.01

<0.01

Na

<0.03

<0.03

0.95

P

0.25

<0.02

0.65

Zn

3.5

2.7

6.1

Cl

23.5

23.5

0.2

Br

70.5

2.4

5.9

Sb

6.5

12.0

5.0

S

2.2

2.5

0.45

The qualitative GC-MS assignments obtained on the chloroform extract from the sample (Figure 17) were as follows:

The qualitative GC-MS assignments of the volatile species trapped onto Tenax (Figure 18) were as follows:

trichloromethane

carbon disulfide

formamide

benzene

N,N-dimethyl formamide

toluene

cyclohexanethiol

aliphatic hydrocarbons

phenol

N,N-dimethyl formamide

N,N-dimethyl urea

cyclohexanone

heptane, 3-(bromomethyl)-

cyclohexanethiol

benzothiazole

phenol

urea

acetophenone

phthalimide

heptane, 3-(bromomethyl)-

phenol, 4-(1,1,3,3-tetramethylbutyl)-

benzothiazole

aliphatic hydrocarbons

butanoic acid, 2-methylpropyl ester

aliphatic carboxylic acids

phenol, 4-(1,1,3,3-tetramethylbutyl)-

di-(2-ethylhexyl) phthalate

N-phenylbenzeneamine

2-ethylhexyl diphenyl phosphate

phthalimide

35

Rubber Analysis – Polymers, Compounds and Products

Figure 17 GC-MS chromatogram of a chloroform extract of the unknown sample

Figure 18 GC-MS chromatogram of the volatile species from the unknown sample trapped onto Tenax

36

Rubber Analysis – Polymers, Compounds and Products

The two sets of GC-MS data confirm the presence of a phosphate (and identify it as 2-ethylhexyl diphenyl phosphate) and identify a phthalate (DEHP). The identification of urea in the chloroform extract could mean that a flame retardant such as guanyl urea is present in the sample. There is also information on the cure and antidegradant systems:

The bromine content of the as received sample was determined using the oxygen flask combustion technique, but with ion chromatography as the final step to separate the bromine and chlorine species. The sulfur content of the methanol extracted portion of the sample was also determined using the oxygen flask combustion technique. The nitrogen content of the sample in the as received state was determined using a Perkin Elmer 2400 CHN analyser.

Assigned species

Possible origin

Cyclohexane thiol

CBS accelerator

Benzothiazole

MBT/MBTS (also the CBS) accelerators

N,N-Dimethyl formamide

TMTD accelerator

Phthalimide

Santoguard PVI vulcanisation inhibitor)

N-Phenylbenzene amine

Possibly an acetone/diphenyl amine antioxidant

10.3.2 Solid State Nuclear Magnetic Resonance (pre-

10.3 Additional Tests Having determined that the sample is based on a blend of polymers and contains a number of flame retardants (both organic and inorganic), there are a number of tests that can be carried out to obtain quantification data on the constituents identified in Section 10.2. Additional tests are also carried out to see if any species may have been overlooked from the results of the initial tests.

10.3.1 Elemental Determinations The following elements were quantified in both the sample as received and on the sample ash using ICP: antimony zinc aluminium phosphorus boron. In addition, the combined chlorine and bromine content of the sample as received and in the methanol extracted portion were determined using the oxygen flask combustion technique with titration as the final stage. The method used was that described in BS 7164, Section 22.2 (1992).

The methanol extracted portion of each sample was analysed by cross-polarised solid state NMR to further investigate the polymer content, and ensure that the IR work had not overlooked anything.

10.4 Results From the Additional Tests The chlorine content of the extracted portion of the sample was 13.73%. This will have originated from the PVC in the sample and can be used to calculate the amount by adjusting for the level of methanol extract and then using the fact that PVC contains 56.8% chlorine. 100 - Extract value x 13.73 x 100 = 15.8% PVC 100 56.8 Assuming the acrylonitrile content of the nitrile rubber in the PVC/nitrile rubber blend is 36% (i.e., a medium acrylonitrile content nitrile rubber), the amount of nitrile rubber in the sample can be calculated in the same way as the PVC content. The nitrogen content of the extracted portion of the sample was 3.39% and the percentage of nitrogen in 36% acrylonitrile nitrile rubber is 9.5%. 100 - Extract value x 3.39 x 100 = 23.3% nitrile rubber 100 9.5 The quantifications for the other elements are shown in Table 9.

37

Rubber Analysis – Polymers, Compounds and Products

10.5 Summary of the Data on the Sample

Table 9 Quantification results for other elements in the unknown sample As received

Sample ash

Antimony

1.38%

2.12%

Zinc

0.41%

2.35%

Boron

<0.05%

<0.05%

Aluminium

7.03%

37.8%

Phosphorous

0.22%

1.36%

The data obtained on the sample can be summarised as shown in Table 10. The quantifications are only approximate. The solid state NMR spectrum for the sample (Figure 19) showed peaks at shift values of 45.6 and 57 ppm which were due to the PVC, and shifts at 33 and 130 ppm due to the nitrile rubber. This data therefore corroborated the assignments made by pyrolysis IR. In addition to the flame retardants given above, guanyl urea could be in the sample (see GC-MS data). This type of additive can be present at around the 3% level.

The above data shows that the flame retardant zinc borate is not present in the sample; the flame retardants hydrated alumina and antimony trioxide are present at 20% and 2%, respectively; and zinc oxide is present at 2%. The bromine content of the as received sample was 8.63%. This will have come from the brominated flame retardant and shows that the sample contains around 13% by weight.

As with all rubber samples, work could continue, and the obvious step would be to carry out further work by solvent extraction HPLC to obtain quantifications for the 2-ethyl hexyl diphenyl phosphate and the di-(2ethylhexyl)phthalate. The complexity of rubber compounds, particularly of this type, precludes a complete characterisation by

Table 10 Summary of the analytical data on the unknown sample Polymers present

nitrile rubber and PVC in a blend having the approximate ratio nitrile 55:PVC 45

Total polymer content

39%

Organic flame retardants

pentabromodiphenyl ether (13%) 2-ethyl hexyl diphenyl phosphate

Plasticiser

di-(2-ethylhexyl)phthalate

Carbon black content

2%

Total inorganic content

24% zinc oxide 2% hydrated alumina 20% antimony trioxide 2%

Antidegradants

diphenylamine/acetone condensation product

Cure system

sulfur based system

Accelerators

CBS TMTD MBT/MBTS

Other cure system species

PVI

38

Rubber Analysis – Polymers, Compounds and Products

Figure 19 Solid state NMR spectrum for the unknown sample

chemical analysis techniques alone. It is always necessary for the analytical data to be supplemented by input from a rubber technologist in order for a satisfactory copy of the compound to be achieved. It is usually necessary to use the analytical data as a basis for a number of test mixes to ensure that all the relevant properties, e.g., cure behaviour, processibility, durability and, in this case, flame retardancy, are met.

11 Surface Blooms and Product Contaminants

bonding problems in composite systems (e.g., rubber to metal) by interfering with the wetting of the adhesive. In general, for a substance to bloom it must have a relatively low degree of solubility in a rubber matrix, and be present in excess of that solubility. This excess will be present as discrete particles dispersed throughout the matrix and the molecules within these particles will migrate to the surface. There are a number of species that can cause blooms in rubbers: sulfur zinc dithiocarbamates

11.1 Surface Blooms

MBT and ZMBT paraphenylene diamines

The appearance of a bloom on the surface of a rubber product or compound is a relatively common phenomenon that can lead to a number of problems. In the case of rubber products, the bloom can appear during storage or service. A bloom can be an aesthetic problem which effectively categorises the product as a failure as much as poor cure state or air blisters. Blooming can also cause

zinc salts of carboxylic acids (e.g., zinc stearate) paraffinic waxes - usually desirable to provide a physical barrier to ozone and to assist in the migration of antidegradants to the surface. Some blooms can take a long time (e.g., weeks) to appear and in these cases the storage temperature can be critical; a lowering of the temperature reducing the

39

Rubber Analysis – Polymers, Compounds and Products

solubility of the bloom generating species and increasing its migration rate to the surface. The above concerns what is referred to as ‘true’ blooms, but it is also possible for the surface of a rubber to take on the appearance of a bloom if a species has migrated to the surface and undergone a chemical reaction there (modified bloom); if oxidative degradation has produced pitting which scatters light (pseudo bloom); or if contamination has occurred. It is possible to analyse the bloom in situ on the surface of a rubber compound using both IR spectroscopy and Edax. With IR spectroscopy an attenuated total reflectance spectroscopy (ATR) sampling accessory is used and, although an amount of the IR radiation will penetrate through the bloom into the surface of the rubber, it is possible to obtain a spectrum. Unfortunately, the fact that the majority of rubber samples are carbon black filled severely limits the practical use of this approach. Of more interest is the Edax technique (SEM/XRF) which will provide good quality semi-quantitative elemental data on the bloom. A background reading from a freshly cut rubber surface is always obtained in order to gauge the degree of enhancement for each element. SEM can be used in isolation to obtain pictorial representations of the bloom, e.g., sulfur crystals. It is unlikely that Edax data alone will positively identify the culprit species, a viable alternative IR route to ATR is the infrared microscope. A small amount of the bloom is carefully removed from the surface of the rubber and a transmission IR spectrum recorded. This IR spectrum, in combination with the Edax data, is usually very effective in identifying blooms, even when there is more than one compound present. If problems are still encountered, it is possible to remove the bloom using a dry swab technique (to avoid contamination by extractables), the material is taken off the swab in a solvent, such as chloroform, and analysed by GC-MS. This technique has the benefit of a chromatographic separation step and so aids the identification of complex blooms. It is also possible to use other chromatographic techniques such as TLC and HPLC. If the type of microcystalline wax blooming to the surface is required, and sufficient sample is available, DSC can be employed.

Chemical resistance and electrical failure are less likely as this type of contaminant is not usually present at a high enough concentration. Contamination can enter the product stream either in the ingredients used in the production, or during the manufacturing stage (e.g., mixing, extruding or moulding). More often than not this contamination is in the form of solid, discreet entities which makes their removal from the product relatively easy. Once removed, the microscopic techniques IR spectroscopy and Edax are excellent at obtaining assignment data in a cost effective way. Where enough of the contaminant is obtainable (e.g., 1 mg), and if a mixture is suspected, a bulk composition can be obtained by TGA. If identification problems are still occurring, more sophisticated techniques such as GC-MS, SIMS and LIMA can be employed. See also Section 13.2.

12 Analysis of Rubber Latices This section deals with the chemical tests that can be applied to both natural and synthetic rubber latices. There are a number of other tests (e.g., mechanical stability tests) which are outside the scope of this review, but which are covered in reference books on the subject (340).

12.1 Quality Control Tests

12.1.1 Alkalinity The alkalinity of natural rubber latex is defined as the percentage by mass of ammonia (or potassium hydroxide where that chemical has been used as a preservative) that it contains. The alkalinity of a latex is determined by titrating to a value of pH 6.0 in the presence of a stabiliser. The method, described in ISO 125, usually employs electrometric titration, but it is also possible to use methyl red as an indicator.

12.1.2 pH 11.2 Product Contaminants Rubber products can fail, both aesthetically and physically, because of particulate contaminants.

40

The pH of rubber latices is measured with a glass electrode and saturated calomel cell after standardising the pH meter with borax and potassium hydrogen phthalate solutions (ISO 976). A suitable combination electrode may be used

Rubber Analysis – Polymers, Compounds and Products

in place of the single electrodes. The method should give a result that is accurate to 0.1 pH.

12.1.3 Potassium Hydroxide Number This was the first test that was developed as an indicator of latex quality. It is defined as the number of grams of potassium hydroxide that are equivalent to the acid radicals combined with ammonia in latex containing 100 g of total solids. It is determined by potentiometric titration of natural rubber latex with potassium hydroxide solution, after adjustment of the alkalinity and dilution of the latex. The end point of the titration is the point of inflection of the titration curve of pH against volume of added potassium hydroxide (ISO 127).

determined by passing latex serum, obtained by coagulation with acetic acid, through a strong cationexchange resin, followed by evaporation and acidimetric titration (348). The method is time consuming (approximately 4 hours) and requires a measure of expertise.

12.1.7 Higher Fatty Acids (HFA) These are determined, after extraction of latex total solids with acetone, by acidification with sulfuric acid and, after work up, titration with potassium hydroxide solution (348). The VFA number, carbon dioxide number, HFA number and NVA number are all expressed in the same units as the potassium hydroxide number.

12.1.4 Volatile Fatty Acid Number (VFA) This property is determined after coagulating the latex with ammonium sulphate and acidifying the resulting serum by steam distilling the serum in a Markham still and measuring the volatile acids in the distillate by titration with barium hydroxide solution (ISO 506). Prior to the titration it is essential to purge the distillate of carbon dioxide by purging with nitrogen. The most predominant volatile fatty acid in natural latex is acetic acid.

12.2 Chemical Stability Tests Chemical stability tests have been slow to achieve international acceptance because they have been found to be difficult to reproduce, have poor repeatability, or a questionable relevance to industrial latex processes.

12.2.1 Natural Rubber Latices 12.1.5 Carbon Dioxide Number This is determined by either the microabsorption method (351) or the macrobaryta technique (346) after acidifying stabilised latex. The carbon dioxide number usually has a value about 0.12 greater than the VFA number and so is an alternative indicator of the level of preservation of natural latex. The potassium hydroxide number (Section 12.1.1) collectively determines volatile fatty acids, carbonate/ bicarbonate (carbon dioxide number), non-volatile acids, higher fatty acids and other acidic species. Given that higher fatty acids are stabilising, whereas the other acidic species are all destabilising reduces the value of the potassium hydroxide number as a measure of latex quality, since it adds together stabilising and destabilising components.

12.1.6 Non-Volatile Acids (NVA) These contribute more to the potassium hydroxide number than any of the other acidic groups. NVAs are

Zinc oxide is added to natural rubber latices in a number of industrial processes and so the stability of the latex to zinc ammine ions (from the reaction of zinc oxide with the ammonia preservative) has been the focus of attention. Two particular tests, which have gained prominence, are the zinc stability time (ZST) test (a.24) and the zinc oxide viscosity (ZOV) test (a.25). Other chemical stability tests for natural rubber latex tend to be methods that are modifications of the ZST test or methods that use preformed zinc ammonium acetate.

12.2.2 Synthetic Rubber Latices The chemical stability tests that have been proposed for synthetic latices are more varied and diverse. One widely regarded method involves the addition of a surfactant and zinc oxide dispersion to the latex and measurement of the time taken to initiate coagulation. Other methods determine the amount of coagulum formed by the addition of an electrolyte (e.g., calcium chloride), or methanol.

41

Rubber Analysis – Polymers, Compounds and Products

12.3 Polymer Composition of Synthetic Latices

12.4 Particulate Property Tests

12.3.1 Bound Styrene Content

Test methods for particle properties cover determinations of viscosity, surface tension, soap content, soap deficiency and particle size.

The ISO 3136 method for bound styrene is only applicable to straight SBR latices and not to modified versions such as carboxylated SBR latex. The ISO method 4655 applies to all SBR type latices. In the case of ISO 3136, solid polymer is first prepared by coagulating the latex with sodium chloride and sulfuric acid in the presence of methanol. The polymer is then dried, extracted with ethanol-toluene azeotrope, and then pressed into a thin sheet. The bound styrene value is obtained by refractive index measurements.

12.3.2 Bound Acrylonitrile Content The ISO 3900 method for bound acrylonitrile can be applied to nitrile rubber (NBR) latices, carboxylated versions of NBR, and nitrile-isoprene (NIR) latices. The preparative stage of this method involves the extraction of an air dried film of the nitrile latex with water, to remove water soluble nitrogen containing material and drying to constant mass. The analysis procedure is then the same as that described in ISO 1656 for the determination of the nitrogen content of natural rubber.

12.3.3 Volatile Monomers Instrumental methods for the determination of residual monomers have largely replaced the older international standards that were essentially based on wet chemistry techniques (ISO 2008 for styrene, ISO 3899 for acrylonitrile and ISO 3499 for vinyl acetate). One principal reason for this is that the modern gas chromatographic methods are more sensitive and so give a lower limit of detection. The preferred technique is static headspace GC where the latex is heated in a sealed vial and the headspace analysed for the presence of the monomer. Calibration is usually achieved using the standard addition approach where known amounts of the monomer are added to aliquots of the same latex to ensure that the headspace partitioning remains constant. In the case of monomers such as acrylonitrile, a specific detector (a nitrogen phosphorus detector (NPD)) can be used to achieve very low levels (ppb) of detection. This compares with the old ISO 3899 method which has a detection limit of only 100 ppm.

42

12.4.1 Viscosity There are three international standards for the determination of viscosity: ISO 1652, ISO 2555 and ISO 3219. ISO 1652 is applicable for the determination of the viscosity of rubber latex. In the standard, the Brookfield L instrument is specified for low viscosities (up to 200 mPa.s), the Broofield R instrument for high viscosities (above 2000 mPa.s) and either instrument can be used for intermediate viscosities. The speed of rotation of the viscometer is restricted to 60 rpm for the L instrument and 20 rpm for the R instrument. ISO 2555 is for the determination of the viscosity of dispersions of resins and differs from ISO 1652 in two respects: only the R version of the instrument is specified and there is no restriction on the speed of rotation. However, speeds of 10 and 20 rpm are recommended. ISO 3219 is a general standard for the determination of the viscosity of dispersions of polymers. This standard uses a rotational viscometer working at a defined shear rate. Seven shear rates from 1 to 250 sec-1 are recommended. Since the viscosity of latex increases with its total solids content, as well as depending on the rate of shear used, both total solids content and shear rate should be appended to all viscosity results.

12.4.2 Surface Tension ISO 1409 describes the determination of the surface tension of rubber latex. A du Nouy tensiometer with a platinum ring either 40 or 60 mm in circumference is specified. The latex is required to be at a total solids content of 40% or less. The units of surface tension are mN/m. Surface free energy is synonymous and has the same numerical value as surface tension when it is expressed in units of mJ/m2.

Rubber Analysis – Polymers, Compounds and Products

12.4.3 Soap Content The soap content of synthetic latices that have been produced using potassium oleate can be determined by potentiometric titration with sulfuric acid, after stabilisation with a non-ionic stabiliser and neutralised isopropanol, and adjustment of the pH to at least 11.0 with potassium hydroxide. Two inflection points occur at around pH 9.4 and 5.0. The volume of acid in between these two inflection points is calculated for a latex sample and a blank, and the potassium oleate content is regarded as the difference between the two. Other methods exist for different fatty acid and rosin acid soap systems.

12.4.4 Soap Deficiency The soap deficiency of some latices can be determined by surface tension titration or conductimetric titration with the same soap that is already present in the latex. With surface tension titration, the surface tension is lowered linearly as soap is added. Once the surface of the polymer particles is saturated with adsorbed soap a break in the line occurs and further addition of soap has only a minor effect on surface tension. The amount of soap added to reach the line break represents the soap deficiency of the latex. With conductimetric titration, initially electrical conductance of the latex increases rapidly in a linear way with soap added. As with the former method, once saturation of the particle surface has occurred, the conductance increases more gradually. Again, the soap deficiency is the amount of soap added to reach the break in linearity.

12.4.5 Particle Size There are a number of experimental methods that can be used to determine particle size. These include, electron microscopy, soap adsorption, light scattering, centrifugation, fractional creaming and counting methods.

latex and the molecular adsorption area of the soap need to be known. Light scattering methods measure the intensity of radiation that is scattered by the latex at various angles to the direction of incidence. Centrifuge methods depend on the difference in density between the particles and the serum in which they are dispersed. The Coulter Counter is a useful instrument for measuring the size distribution of latex particles in the diameter range 40 to 3000 μm. Fractional creaming was developed by Schmidt and Biddison (a.27). The method uses the quantitative inverse relationship between concentration of a creaming agent (sodium alginate) and the size of creamed particles.

12.5 Miscellaneous Chemical Tests There are international standards for the determination of copper (ISO 1654), manganese (ISO 1655), nitrogen (ISO 1656) and iron (ISO 1657). The test for nitrogen only applies to natural rubber latex, whereas the others can be used for both synthetic and natural latices. The nitrogen content of natural rubber latex may be used to obtain an estimate of its protein content by applying a factor of 6.25. Other metals and elements in latex can be obtained by using atomic absorption spectroscopy. ISO 1802 describes the determination of the boric acid content of the LABA type (boric acid and sodium pentachlorphenate secondary stabilisers, with ammonia as the primary stabiliser) of natural rubber latex. The test involves complexing the boric acid with mannitol and titrating the liberated hydrogen ions with alkali.

13 Failure Diagnosis To be amenable to electron microscopy, rubbery latex particles have to be hardened, for example by bromination, to prevent distortion or coalescence. Soap adsorption methods (a.26) require the latex to have a soap deficiency. The initial soap content of the

It is an unfortunate fact that some rubber products fail in service. One of the major reasons for this is an incorrect formulation of the product initially, which is a technological failing, the other is where the formulation is correct for the application, but where

43

Rubber Analysis – Polymers, Compounds and Products

there has been a problem in the mixing/processing side, leading to a product that does not meet the specification. Analysing the failed rubber component can be used to prove the latter case. Rubber components may not be fit for purpose for other reasons. These may relate to perceived health and safety issues (e.g., contamination of a seal for a pharmaceutical application), or aesthetic considerations (e.g., blooms and odours). The analysis of blooms has been considered in Section 11. The most prevalent cause for a rubber failure which is solely processing related is poor cure state and this has been discussed in Section 9.

13.1 Compositional Problems On occasions a rubber product may fail in service and work needs to be undertaken to find out why. If it is suspected that the composition of the product is not correct, for example that the antioxidant or correct cure system has not been incorporated into the compound, then the appropriate species specific tests that have been discussed earlier can be carried out. If possible, it is advisable to conduct the analysis alongside that of a sample known to be of the correct composition. This ensures that no product specific matrix effects/ interference reactions will affect the data obtained and hence the conclusions reached. The mode of failure (e.g., swelling, cracking or hardening) can provide useful hints as to the possible reason for failure. For example swelling can be due to the use of an incorrect polymer type - natural rubber instead of nitrile. It is always advisable, though, to ensure that the conditions of service are as specified and that the product has not been subjected to excessive temperatures or corrosive media. A surprisingly large number of failure problems can be solved by carrying out a simple series of tests that include a polymer identification check by IR spectroscopy, a quantitative extraction followed by analysis of the extract by IR spectroscopy, and a bulk compositional analysis by TGA. The extraction/IR approach is very useful in dealing with a situation where a rubber has absorbed a fluid in service; an identification and quantification of the fluid being obtained.

44

13.2 Contamination Problems A number of rubber products can suffer from solid inclusions, but it is probably most common in extruded products such as car door seals. The most effective approach to these types of contamination problems is to employ both a spectroscopy technique (IR microspectrometry) and an elemental technique, such as energy dispersive analysis (Edax). In this way both organic and inorganic possibilities are covered, and indications as to whether the inclusion is a mixture of components obtained. Contamination of rubber products by a species at a low (i.e., less than 1% or at ppm levels) can sometimes be important, for example if the rubber is to be used in the pharmaceutical industry. If it is suspected that the contaminant is, or contains, a metal, then AAS can be employed. If the presence of an organic molecule is suspected, then headspace GC-MS can be used to identify and quantify the species. The high sensitivity of this technique normally makes the use of a control sample extremely important for a quick interpretation of the output, which is often complex.

13.3 Odour and Emissions Problems The continuing drive to improve customer care and the high profile of health and safety issues, has led to pressure on the suppliers of rubber components to certain industries to minimise odours, and volatiles in general, from their products. This is particular true of the automotive industry. There are a number of specific tests that automotive companies insist that rubber components have to pass. An example of such a test is the VW emissions test which involves placing the component in a cell of given dimensions and heating the cell for a given time at a specified temperature. Rather than carry out a detailed analysis of the components liberated from the rubber component, the result is expressed in terms of ppm of total organic compounds as determined by an organic vapour analyser (OVA). Limits are given as to the permissible concentrations allowed. Other car manufacturers’ emission tests are based on static headspace GC with FID detection. The emissions are expressed as the total area of all the species peaks obtained and are quantified against a single species calibration curve.

Rubber Analysis – Polymers, Compounds and Products

For odour quality control purposes, it is the case at present that human smell panels will be used in preference to instrumental analytical techniques, which do not yet adequately mimic the human response. There are practical drawbacks to this approach, which has lead to a lot of research going into ‘electronic noses’ utilising a number (e.g., 32) of sensors based on organic conducting polymers. These devices enable fingerprints of satisfactory products to be recorded which are used as references for quality checks. Car products such as car mats are also being formulated to reduce the amount of odour given off by them . This is often a difficult requirement to meet as the typical additives that go into this sort of product (e.g., pine tar and reclaim rubber) are, by their very nature, smelly. Finding cost equivalent replacements for these additives is difficult. Work has been carried out to determine the additives which contribute the most to the overall odour of these products. One of the most useful techniques is headspace GC-MS. It is advisable to use the dynamic form of headspace sampling as this enables the volatiles from the sample to be concentrated. This benefit is important as some chemical species can cause an odour problem at very low levels due to the specific sensitivity of the human nose. For example, it has been found that hydrogen sulfide can be detected at a level of 0.5 ppb (parts per billion) in the atmosphere. For this type of work the dynamic headspace sampler (e.g., the Perkin Elmer ATD 400) is operated in a diffusion mode where the sample is heated at a relatively low temperature (e.g., 50 °C), which helps to ensure that additional volatile species are not generated due to degradation of the sample, for a relatively long period of time (e.g., in excess of 30 minutes). This contrasts with the 10 minutes at 150 to 180 °C protocol used to determine cure systems, etc. (Section 7). The odour species collected in the trap of the dynamic headspace sampler can then be analysed under the following conditions: Headspace trap injection temperature

200 °C

GC column type

SGE RTX5 MS 30 m x 0.25 mm, 0.25 μm film

GC column temperature (cryogenic cooling)

–30 °C to 50 °C at 5 °C/min and then 20 °C/ min to 320 °C

MS conditions

20 to 450 atomic mass units scanned every 0.33 seconds

In addition to certain plasticisers and process aids, odours can be associated with cure system breakdown products. This is particularly true in the case of the pharmaceutical industry where rubber products are often cured using peroxides because the system is generally ‘purer’, but a postcure autoclave or oven bake is required to clean up the rubber matrix. Once again, headspace GC-MS can be used to confirm if a residual odour is due to a flaw in this clean up procedure.

14 Conclusion This review describes the analysis of rubbers, rubber compounds and rubber products in as comprehensive a way as is possible within the format of a Rapra Review Report. The subject matter has been kept as broad as possible to maximise the usefulness of the publication, whilst trying to maintain a reasonable balance between breadth and depth. The abstracts and additional reading references provided should greatly assist the analyst who requires more information, both specific and general. Although an attempt has been made to include as much information as possible, the subject of rubber analysis is so large that it is inevitable that certain analytical techniques and methods will have been excluded or only given a cursory mention. For the future, the reduction in cost of LC-MS systems will increase their accessibility and, in combination with GC-MS, will greatly improve the efficiency and accuracy with which the analysis of antidegradants, cure systems, plasticisers and other additives can be carried out. Developments are also taking place in the thermal analysis field. The modulated/dynamic DSC instrument should prove useful for providing more information on curing and thermal stability characteristics. The modulated TGA (for decomposition kinetics), the high resolution TGA (for improved weight loss event resolution), and the Micro Thermal Analyser, which can be used to obtain a wide range of thermal property data (e.g., thermal conductivity and diffusivity) on very small samples, are other examples. It is clear that, even with the development of new and more advanced techniques, the analysis of rubber compounds and products will continue to present the polymer analyst with complex and difficult challenges.

45

Rubber Analysis – Polymers, Compounds and Products

Additional References

a.14

C.W. Sweitzer, W.M. Hess and J.E. Callan, Rubber World, 1958, 138, 6, 869.

a.1

G. Lawson and J. Sidwell, Plastics and Rubber International, 1983, 8, 6, 15.

a.15

N.A. Stumpe and H.E. Railsback, Rubber World, 1964, 151, 3, 41.

a.2

J.J. Leyden and J.M. Rabb, Elastomerics, April 1980, 34.

a.16

W.C. Warner, J. Chromat., 1969, 44, 315.

a.3

T.R. Crompton, Practical Polymer Analysis, Plenum Press, 1993.

a.17

Kriener, Rubber Chemistry and Technology, 1971, 44, 381.

a.4

M.J.R. Loadman, Analysis of Rubber and Rubber-like Polymers, 4th Edition, Kluwer Academic Publishers, 1998.

a.18

K. Nagasawa and K. Ohta, Rubber Chemistry and Technology, 1969, 42, 625.

a.19

H.B.S Conacher and B.D. Page, J Chromatog. Sci., 1979, 17, 188.

a.20

B.G. Willoughby and K.W. Scott, Nitrosamines in Rubber, Rapra Technology Ltd., 1997.

a.21

G.P. McSweeny, J. IRI, 1970, 4, 243.

a.22

F. McLafferty and D.B. Stauffer, Wiley/NBS Registry of Mass Spectral Data, John Wiley & Sons, 1989.

a.23

D.W. Brazier, Rubber Chemistry and Technology, 1980, 53, 457.

a.24

J.L.M. Newnham, K.O. Calvert and D.J. Simcox, Proc. Nat. Rubb. Res. Conf., Kuala Lumpar, 1961, 668.

a.25

H.G. Dawson, Rubber World, 1956, 135, 239.

a.26

S.H. Maron, M.E. Elder, I.N. Ulevitch and C. Moore, J. Coll. Sci., 1954, 9, 89, 104, 263, 347, 353 and 382.

a.27

E. Schmidt and P.H. Biddison, Rubb. Age, NY, 1960, 88, 484.

a.5

P.J. Wyatt, Anal. Chim. Acta., 1992, 272, 1.

a.6

W.M. Hess, L.L. Ban and G. McDonald, Paper to Rubber Div. Am. Chem. Soc. Meeting, 1969.

a.7

T.G. Lamond and C.R. Gillingham, 1970, Rubber Journal, 152, 65.

a.8

M-J Wang, S. Wolff and J-B Donnet, Rubber Chemistry and Technology, 1991, 64, 714.

a.9

R.P. Hjelm, W.A. Wampler, P.A. Seeger and M. Gerspacher, J. Mat. Res., 1994, 9, 3210.

a.10

T.C. Gruber, T.C. Zerda and M. Gerspacher, Carbon, 1993, 31, 1209.

a.11

T.C. Gruber, T.C. Zerda and M. Gerspacher, Carbon, 1994, 32, 1377.

a.12

J.A. Ayala, W.M. Hess, A.O. Dotsan and G.A. Joyce, Rubber Chemistry and Technology, 1990, 63, 747.

a.13

A.I Medalia and D.F. Walker, Evaluating Dispersion of Carbon Black in Rubber, Technical Report RG-124 Revision 2, Cabot Corporation, Carbon Black Division, Boston, Mass., 1970.

46

Rubber Analysis – Polymers, Compounds and Products

APPENDIX 1 Standard Nomenclature System for Rubbers

ECO

Copolymer of epichlorohydrin and ethylene oxide (Herclor C)

The nomenclature system used in the rubber industry is based on ISO 1629-1976. The last letter of the identification code defines the basic group to which the polymer belongs, whilst the first letters provide more specific information relating to the polymer’s structure.

GPO

Copolymer of propylene oxide and allyl glycidyl ether (e.g., Parel)

Appendix 1.1 M Group: Rubbers having a saturated carbon-carbon main chain IM

Polyisobutylene (e.g., Vistanex)

EPM

Copolymer of ethylene and propylene having monomer ratios between 70-30 and 30-70 wt/wt

EPDM

Terpolymer of ethylene, propylene and a small amount of a third diene monomer allowing the use of a sulfur based cure system. (e.g., Nordel)

CM

Chlorinated polyethylene (e.g., CPE) Two grades are available; one containing 36% chlorine by weight and the other 42% chlorine by weight.

CSM

Chlorosulfonated polyethylene (e.g., Hypalon) The polymers contain varying amounts of chlorine (20-45%) and sulfur (0.5-2.5%). The optimum values are Cl (30%): S (1.5%).

Appendix 1.3 Q Group: Silicone rubbers MQ

Polydimethyl siloxane - can be an oil, wax or rubber depending on molecular weight

MPQ

MQ with the presence of some phenylmethyl siloxane units in the backbone

MPVQ

MPQ with the presence of some vinylmethyl siloxane units in the backbone

MFQ

Fluorinated MQ - degrees of fluorination can vary

Appendix 1.4 R Group: Rubbers having an unsaturated carbon backbone ABR

Copolymers of butadiene and methyl methacrylate (e.g., Butakon ML) Also: terpolymer of butadiene, methyl methacrylate and acrylonitrile and tetrapolymer of butadiene, methyl methacrylate, acrylonitrile and styrene

BR

Polybutadiene - can vary greatly in trans 1,4 , cis 1,4 and vinyl content General purpose rubbers are usually 90% cis 1,4 or approximately 45% cis 1,4, 45% trans 1,4 and 10% vinyl

CR

Polychlorobutadiene (e.g., Chloroprene and Neoprene). There are two principal types: G types which are amber coloured copolymers with sulfur and have a molecular weight of approximately 100,000 W types which are white coloured homopolymers and have a molecular weight of approximately 200,000

IIR

Appendix 1.2 O Group: Rubbers having carbon and oxygen in the main chain

Copolymer of isobutylene and a small amount of isoprene (butyl rubber) to provide cure sites

CIIR

Chlorinated IIR 2-3% w/w

CO

BIIR

Brominated IIR 2-3% w/w

FPM

CFM

Fluorocarbon rubbers having fluoro/ fluoroalkyl groups on the saturated carbon backbone e.g., VITON A - copolymer of hexafluoropropylene and vinylidene fluoride e.g., Technoflon - copolymer of vinylidene fluoride and 1-hydropentafluoropropylene Fluorochlorocarbon rubbers e.g., Kel F - copolymer of vinylidene fluoride and chlorotrifluoroethylene

Polyepichlorohydrin (e.g., Herclor H)

47

Rubber Analysis – Polymers, Compounds and Products

IR

NBR

NR

SBR

Synthetic cis 1,4 polyisoprene (e.g., Natsyn and Cariflex) Cis 1,4 level 90-99% with the remainder trans 1,4 and vinyl Copolymer of acrylonitrile and butadiene (e.g., Krynac) Acrylonitrile content of the random copolymer can vary between 15 to 50% to change the degree of oil resistance Two important modified versions of NBR are hydrogenated nitrile rubber (where the double bonds in the butadiene segments are removed by hydrogenation) and carboxylated nitrile rubber which, in addition to acrylonitrile and butadiene units, contains some carboxyl groups. Natural rubber Natural rubber consists of 96% polymer which is virtually 100% cis 1,4 with trans 1,4 and vinyl content at <0.1%. The other 4% is made of natural products such as proteins There is a wide variety of natural rubber grades, e.g., RSS (Rib Smoked Sheet) and SMR (Standard Malaysian Rubber). These denominations are accompanied by numbers denoting purity and quality, e.g., RSS 1 and SMR 10 There are also modified natural rubbers available, such as epoxidised natural rubber (ENR) Copolymer of styrene and butadiene The styrene level in the random copolymer can vary between 10 and 80%, but the general purpose grade contains around 23%. There are many grades available and these are identified by a specific coding system

Appendix 1.5 T Group: Rubbers having carbon, oxygen and sulfur in the main chain

Appendix 1.6 U Group: Rubbers containing carbon, oxygen and nitrogen in the main chain AU

Polyester type polyurethanes

EU

Polyether type polyurethanes A wide range of polyurethanes can be produced by making use of a number of different isocyanates, polyols and chain extenders

Appendix 1.7 Other Rubbers - General designations and descriptions ACM

Acrylic rubbers Polynorbornene Polyfluorophophazene rubbers Ethylene acrylic rubber (e.g., Vamac)

EVA

Ethylene vinyl acetate (elastomeric in the range 40-60% vinyl acetate)

Appendix 1.8 Other polymer related acronyms which are commonly encountered in the Rubber industry include: TPR

Thermoplastic rubber e.g., MG Rubber, natural rubber that has had methyl methacrylate grafted onto it to produce a material containing 30% or 49% methyl methacrylate

HNBR

Hydrogenated nitrile rubber

XNBR

Carboxylated nitrile rubber

Appendix 1.9 Other naturally occurring polyisoprenes include: GuttaPercha 100% trans 1,4 polyisoprene

OT

EOT

48

Copolymer of bis-chloroalkyether (or formal) with sulfur e.g., Thiokol ST - bis-2-chloroethylformal, sulfur and 1,2,3-trichloropropane as a cure site monomer OT monomers polymerised with ethylene dichloride. e.g., polyethylene disulfide and polybutyl ether disulfide

Balata

100% trans 1,4 polyisoprene

Chicle

Mixture of 25% cis 1,4 and 75% trans 1,4 polyisoprene (used in chewing gum manufacture)

Guayule 100 cis 1,4 polyisoprene

Rubber Analysis – Polymers, Compounds and Products

6528-3

Rubber - Determination of total sulfur content - Part 3: Furnace combustion method 1988

7269

Rubber - Determination of free sulfur 1995

8054

Rubber, compounded or vulcanized Determination of sulfide sulfur content Iodometric method 1996

7725

Rubber and rubber products Determination of bromine and chlorine content - Oxygen flask combustion technique 1991

3865

Rubber, vulcanized or thermoplastic Methods of test for staining in contact with organic material 1997

4648

Rubber, vulcanized or thermoplastic Determination of dimensions of test pieces and products for test purposes 1991

Glass capillary kinematic viscometers Specifications and operating instructions 1994

4661-1

Rubber, vulcanized or thermoplastic Preparation of samples and test pieces Part 1: Physical tests 1993

Petroleum products - Transparent and opaque liquids - Determination of kinematic viscosity and calculation of dynamic viscosity 1994

4661-2

Rubber, vulcanized - Preparation of samples and test pieces - Part 2: Chemical tests 1987

5945

Rubber - Determination of polyisoprene content 1989

4645

Rubber and rubber products - Guide to the identification of antidegradants - Thin layer chromatographic methods 1984

11089

Rubber, raw synthetic - Determination of anti-degradants by high-performance liquid chromatography 1997

10398

Rubber - Identification of accelerators in cured and uncured compounds 1998

1407

Rubber - Determination of solvent extract 1992

4650

Rubber - Identification - Infra-red spectrometric method

APPENDIX 2 International Rubber Analysis Standards (ISO)

Appendix 2.1 General ISO Standards Standard number Title

Year

1382

Rubber - Vocabulary

1996

1629

Rubber and latices - Nomenclature 1995

565

Test sieves - Metal wire cloth, perforated metal plate and electroformed sheet Nominal sizes of openings 1990

2194

3105

3104

Industrial screens - Woven wire cloth, perforated plate and electroformed sheet Designation and nominal sizes of openings 1991

4661-1

Rubber, vulcanized or thermoplastic Preparation of samples and test pieces Part 1: Physical tests 1993

4661-2

Rubber, vulcanized - Preparation of samples and test pieces - Part 2: Chemical tests 1987

1408

Rubber - Determination of carbon black content - Pyrolytic and chemical degradation methods 1995

2781

Rubber, vulcanized - Determination of density 1988

6528-1

Rubber - Determination of total sulfur content - Part 1: Oxygen combustion flask method 1992

6528-2

1984

Rubber - Determination of total sulfur content - Part 2: Sodium peroxide fusion method 1992

49

Rubber Analysis – Polymers, Compounds and Products

15672

Rubber and rubber additives Determination of total nitrogen content using an automatic analyser 2000

15671

Rubber and rubber additives Determination of total sulfur content using an automatic analyser 2000

9924-1

Rubber and rubber products Determination of the composition of vulcanizates and uncured compounds by thermogravimetry - Part 1: Butadiene, ethylene-propylene copolymer and terpolymer, isobutene-isoprene, isoprene and styrene-butadiene rubbers 2000

1652

Rubber latex - Determination of viscosity 1985

8053

Rubber and latex - Determination of copper content - Photometric method 1995

6101

Rubber - Determination of metal content by atomic absorption spectrometry (5 parts) 1990-1997

7780

Rubbers and rubber latices - Determination of manganese content - Sodium periodate photometric methods 1998

1657

Rubber, raw and rubber latex - Determination of iron content - 1,10-Phenanthroline photometric method 1986

1802

Natural rubber latex concentrate Determination of boric acid content 1992

2004

Natural rubber latex concentrate Centrifuged or creamed, ammonia-preserved types - Specification 1997

Appendix 2.2 Latex ISO Standards Standard number Title

Year

123

Rubber latex - Sampling

124

Latex, rubber - Determination of total solids content 1997

2005

Rubber latex, natural, concentrate Determination of sludge content 1992

125

Natural rubber latex concentrate Determination of alkalinity 1990

2008

126

Latex, rubber, natural concentrate Determination of dry rubber content 1995

Rubber latex, styrene-butadiene Determination of volatile unsaturates 1987

2028

Synthetic rubber latex - Preparation of dry polymer 1999

2438

Rubber latex, synthetic - Codification 1981

3136

Rubber latex - Styrene-butadiene Determination of bound styrene content 1983

127

705

2001

Rubber, natural latex concentrate Determination of KOH number 1995 Rubber latex - Determination of density between 5 °C and 40 °C 1994

706

Rubber latex - Determination of coagulum content (sieve residue) 1985

498

Natural rubber latex concentrate Preparation of dry films 1992

506

976

50

Rubber latex, natural, concentrate Determination of volatile fatty acid number 1992 Rubber and plastics - Polymer dispersions and rubber latices - Determination of pH 1996

-

Appendix 2.3 Carbon Black ISO Standards Standard number

Title

Year

1124

Rubber compounding ingredients - Carbon black shipment sampling procedures1988

1125

Rubber compounding ingredients - Carbon black - Determination of ash 1999

Rubber Analysis – Polymers, Compounds and Products

1126

Rubber compounding ingredients - Carbon black - Determination of loss on heating 1992

1138

Rubber compounding ingredients - Carbon black - Determination of sulphur content 1981

1304

Rubber compounding ingredients - Carbon black - Determination of iodine adsorption number - Titrimetric method 1999

1126

Rubber compounding ingredients - Carbon black - Determination of loss on heating 1992

1437

Rubber compounding ingredients - Carbon black - Determination of sieve residue 1992

1867

Carbon black for use in the rubber industry Specification for sieve residue 1975

1868

Rubber compounding ingredients - Carbon black - Specification limits for loss on heating 1982

3858-1

Carbon black for use in the rubber industry Determination of light transmittance of toluene extract - Part 1: Rapid method 1990

3858-2

4652-1

6894

Carbon black for use in the rubber industry Determination of light transmittance of toluene extract - Part 2: Method for product evaluation 1990 Rubber compounding ingredients - Carbon black - Determination of specific surface area by nitrogen adsorption methods - Part 1: Single-point procedures 1994 Rubber compounding ingredients - Carbon black - Preparation of samples for determination of dibutylphthalate absorption number (compressed sample) 1991

6810

Rubber compounding ingredients - Carbon black - Determination of surface area - CTAB adsorption methods 1995

4656-1

Rubber compounding ingredients - Carbon black - Determination of dibutyl phthalate

absorption number - Part 1: Method using absorptometer 1992 5435

Rubber compounding ingredients - Carbon black - Determination of tinting strength 1994

6209

Rubber compounding ingredients - Carbon black - Determination of solvent extractable material 1998

12245

Carbon blacks used in rubber products Classification system 1994

Appendix 2.4 Standard ISO Test Formulations Standard number Title

Year

1658

Natural rubber (NR) - Evaluation procedure 1994

2302

Isobutene-isoprene rubber (IIR) - Evaluation procedures 1995

2322

Styrene-butadiene rubber (SBR) - Emulsionand solution-polymerized types - Evaluation procedures 1996

2475

Chloroprene rubber (CR) - General-purpose types - Evaluation procedure 1999

2476

Rubber, butadiene (BR) - Solutionpolymerized types - Evaluation procedures 1996

4097

Rubber, ethylene-propylene-diene (EPDM) - Evaluation procedure 2000

4659

Rubber, styrene-butadiene (carbon black or carbon black and oil masterbatches) Evaluation procedure 1997

3257

Rubber compounding ingredients - Carbon black - Method of evaluation in styrenebutadiene rubbers 1992

51

Rubber Analysis – Polymers, Compounds and Products

Appendix 2.5 Statistical Standards Standard number 5725

Title

Year

Accuracy (trueness and precision) of measurement methods and results (6 parts) 1994-2001

248

Rubbers, raw - Determination of volatilematter content 1991

249

Rubber, raw natural - Determination of dirt content 1995

1407

Rubber - Determination of solvent extract 1992

3534

Statistics - Vocabulary and symbols (3 parts) 1993-1999

1434

Natural rubber in bales - Amount of bale coating - Determination 1995

2859

Sampling procedures for inspection by attributes (5 parts) 1985-2001

8053

Rubber and latex - Determination of copper content - Photometric method 1995

2602

Statistical interpretation of test results Estimation of the mean - Confidence interval 1980

7780

Rubbers and rubber latices - Determination of manganese content - Sodium periodate photometric methods 1998

2854

Statistical interpretation of data - Techniques of estimation and tests relating to means and variances 1976

6101

Rubber - Determination of metal content by atomic absorption spectrometry (5 parts) 1990-1997

3207

Statistical interpretation of data Determination of a statistical tolerance interval 1975

1656

Rubber, raw natural, and rubber latex, natural - Determination of nitrogen content 1996

1657

Rubber, raw and rubber latex - Determination of iron content - 1,10-Phenanthroline photometric method 1986

1795

Rubber, raw natural and raw synthetic Sampling and further preparative procedures 2000

2000

Rubber, raw natural - Specification 1989

7781

Rubber, raw styrene-butadiene Determination of soap and organic-acid content 1996

2453

Rubber, raw styrene-butadiene, emulsionpolymerized - Determination of bound styrene content - Refractive index method 1991

4660

Rubber, raw natural - Colour index test 1999

7270

Rubber - Identification of polymers (single polymers and blends) - Pyrolytic gas chromatographic method 1987

3301

3494

Statistical interpretation of data Comparison of two means in the case of paired observations 1975 Statistical interpretation of data - Power of tests relating to means and variances1976

Appendix 2.6 Raw and Compounded Rubber Standards Standard number

Title

Year

3899

Rubber - Nitrile latex - Determination of residual acrylonitrile content 1988

3900

Rubber - Nitrile latex - Determination of bound acrylonitrile content 1995

4655

Rubber - Reinforced styrene-butadiene latex - Determination of total bound styrene content 1985

247

Rubber - Determination of ash

52

1990

Rubber Analysis – Polymers, Compounds and Products

5945

Rubber - Determination of polyisoprene content 1989

Identification of polymers by pyrolysis GC ISO/DIS 7270

6235

Rubber, raw - Determination of block polystyrene content - Ozonolysis method 1995

Determination of soap and organic acid content of raw SBR ISO/DIS 7781

247

Rubber - Determination of ash

2454

Rubber products - Determination of zinc content - EDTA titrimetric method 1995

Molecular weight determination of solution polymerised rubbers by GPC ISO/DIS 11344

7780

Rubbers and rubber latices - Determination of manganese content - Sodium periodate photometric methods 1998

Determination of residual monomers and other organic compounds by GC. Part 1: Automated thermal desorption method ISO/DIS 17052-1

1657

Rubber, raw and rubber latex - Determination of iron content - 1,10-Phenanthroline photometric method 1986

Determination of residual monomers and other organic compounds by GC. Part 2: Headspace method ISO/DIS 17052-2

8053

Rubber and latex - Determination of copper content - Photometric method 1995

Determination of residual monomers and other organic compounds by GC. Part 3: Direct liquid injection method ISO/DIS 17052-3

1990

Appendix 2.7 ISO Standards in Preparation Extractable proteins in NR medical gloves ISO/CD12243 Sulphenamide type accelerators, method of test ISO/11235 p-Phenylenediamine antidegradants, test methods ISO/11236 Carbon black – iodine number, potentiometric method ISO/DAM/1304

Determination of ENB or DCPD in EPDM ISO/DIS 16565

Determination of composition by TGA (NBR, CIIR, BIIR, XNBR and HNBR) ISO/DIS 9924-2 Polymer dispersions and rubber lattices (natural and synthetic) – Definitions and review of test methods ISO/FDIS 12000 Rubber, raw styrene-butadiene – Determination of soap and organic acid content ISO/DIS 7781 Rubber, raw natural – Determination of molecular weight by GPC Not decided

Determination of composition in selected polymers ISO/DIS 9924 Determination of microstructure of BR by IR ISO/DIS 12965 Rubber compounding ingredients – petroleum oils – methods of test and classification ISO/CD 20139 Determination of unsaturation in HNBR by iodine value ISO/DIS 17564 Determination of unsaturation in HNBR by IR ISO/DIS 14558

53

Rubber Analysis – Polymers, Compounds and Products

crosslinking a rubber will raise its Tg, but because the usual levels of crosslink density are relatively low this effect is not very pronounced. High levels of interaction between the rubber and large scale additives such as fillers will also increase the Tg of a rubber compound, whereas the incorporation of a plasticiser or oil will usually lower it.

APPENDIX 3 Glass Transition Temperatures of Rubbers The method of measuring the glass transition temperature (Tg) of a rubber (or any other polymer) will influence the actual number obtained. In general, the greater the time that the rubber is give to respond to the forces acting on it the lower the Tg will be. For example, the figure obtained for a torsion pendulum experiment where mechanical flexing at a low frequency is involved will be lower that that obtained on the same sample by DSC. It is also the case that

Representative Tg values for a range of commercial rubbers obtained using DSC in the gum (i.e., uncompounded and unvulcanised state) are given in Table 11.

Table 11 Tg values for a range of commercial rubbers obtained using DSC Rubber Type

Tg (°C)

Comments

Polyisobutylene

-70

EPM

-60

(50:50 monomer mix)

EPDM

-6 6

Nordel 1470/1660

Chlorosulphonated polyethylene

+9

Hypalon 30

Fluorocarbon

-1 8

Viton B

Hydrin copolymer

-4 7

Herclor C

GPO

-7 3

Parel 58

Polydimethyl siloxane

-127

Phenylmethylsiloxane

-86

Vinylphenylmethylsiloxane

-86

ABR

-57

At 25% methylmethacrylate

Polybutadiene

-107

100% 1,4 or 100% trans 1,4

-15

100% vinyl

Polychloroprene Butyl rubber

-45 -67 to -75

Depends upon level of isoprene

Halogenated butyl rubber

-70

Synthetic polyisoprene

-68

Natural rubber

-72

Nitrile rubber

-65

15% acrylonitrile

0

50% acrylonitrile

SBR

-60

23.5% styrene

-38

36% styrene

Thiokol ST

-59

Polybutyl ether disulfide

-76

Polyester urethanes

-30

Varies with structure

Polyether urethanes

-5 0

Varies with structure

54

Rubber Analysis – Polymers, Compounds and Products

APPENDIX 4 Maximum Service Temperatures and Relative Stabilities of Different Rubber Types to Various Degradation Agencies

Appendix 4.1 Maximum service temperatures for a range of rubbers Maximum service temperature (°C) Polyurethane rubber 80 Natural rubber and polyisoprene rubber 80 Butadiene rubber and styrene-butadiene rubber 100 Nitrile rubber and polychloroprene rubber 120 Butyl rubber 130 Ethylene-propylene type rubbers 140 Chlorosulfonated polyethylene 150 Hydrogenated nitrile rubber 160 Acrylic rubber 160 Silicone rubber 225 Fluorocarbon rubber 250

Silicone rubber Chlorosulfonated polyethylene Nitrile rubber Fluorocarbon rubber Polychloroprene Styrene-butadiene rubber Ethylene-propylene rubber Polyurethane rubber

Up to 100,000 Up to 100,000 Up to 100,000 Up to 100,000 Up to 100,000 Up to 500,000 Up to 500,000 Up to 500,000

Rubber Type

Appendix 4.2 Thermal decomposition temperatures of a range of rubbers Rubber Type

Temperature to achieve 50% decomposition* (°C) Polyisoprene rubber 323 Nitrile rubber 360 Styrene-butadiene rubber 375 Chlorosulfonated polyethylene 380 Polychloroprene rubber 380 Ethylene-propylene type rubbers 388 Butadiene rubber 407 Silicone rubber 560 *The temperature at which 50% mass loss occurs in a specified time interval

Appendix 4.3 Gamma radiation resistance of a range of rubbers Rubber Type Butyl rubber Acrylic rubber

Insignificant damage (Radiation dose, Gy) Up to 10,000 Up to 100,000

Appendix 4.4 Resistance to ozone The relative resistance of a number of rubbers in the unstabilised state to ozone is shown below:

Rubbers with very poor resistance

Diene rubbers (e.g., natural rubber, styrenebutadiene rubber, nitrile rubber, butadiene rubber)

Rubbers having some resistance

Butyl rubbers, hydrins, hydrogenated nitrile, polythioethers, polychloroprene

Rubbers having good resistance

Acrylics, chlorosulfonated polyethylene, ethylenepropylene rubbers, fluorocarbon rubbers, silicone rubbers

APPENDIX 5 Solubility Parameters of Rubbers and Typical Solvents

Appendix 5.1 Solubility parameters of rubbers Rubber Type Solubility Parameter Natural rubber 7.9-8.5 Polyisoprene 7.9-8.5 SBR (4-40% Styrene) 8.1-8.6 Butadiene rubber 8.0-8.6 Butyl rubber 7.5-8.0 EPDM 7.5-8.6 Chloroprene rubber 8.1-9.4 Nitrile rubber (18-30% acrylonitrile) 8.7-9.3

55

Rubber Analysis – Polymers, Compounds and Products

Nitrile rubber (40% acrylonitrile) Silicone rubbers Polysulfide rubbers Polyurethane rubbers PVC (used in blends with Nitrile)

10.4-10.5 7.0-11.0 9.0-10.0 9.8-10.3 8.5-11.0

Appendix 5.2 Solubility parameters of solvents Solvent n-Hexane Diethyl ether Cyclohexane Carbon tetrachloride Xylene Toluene THF Chloroform Methyl ethyl ketone (MEK) Trichloroethane Dichloromethane (DCM) Cyclohexanone N,N-Diethyl acetamide Acetone o-Dichlorobenzene Carbon disulfide N,N-Diethyl formamide n-Butanol Cyclohexanol Acetonitrile N,N-Dimethylformamide Ethanol Dimethylsulfoxide Methanol Ethylene glycol Water

Solubility Parameter 6.6 7.4 8.2 8.6 8.8 8.9 9.1 9.3 9.3 9.6 9.7 9.7 9.9 9.9 10.0 10.0 10.6 11.4 11.4 11.9 12.1 12.7 12.9 14.5 14.6 23.4

APPENDIX 6 Specific Gravities of Rubbers and Compounding Ingredients

Appendix 6.1 Specific Gravities of Polymers Polymer Acrylic rubbers Bromobutyl rubber

56

Specific Gravity 1.1 0.91

Butyl rubber 0.91 Chlorobutyl rubber 0.91 Chlorosulfonated polyethylene 1.11-1.28* Epichlorohydrin copolymer 1.27 Epichlorohydrin homopolymer 1.38 Ethylene-propylene rubber 0.85 Ethylene-propylene diene monomer rubber 0.86 Ethylene-vinyl acetate copolymer 0.94 Fluorocarbon rubbers 1.41-1.86* Polyisoprene rubber 0.92-0.93 Natural rubber 0.92-0.93 Nitrile rubbers 0.95-1.00* Nitrile/PVC blends 1.0-1.11* Polybutadiene rubbers 0.91-0.93 Polychloroprene rubbers 1.23-1.25* Polynorbornene 0.96 Polysulphide rubbers 1.27-1.60* Styrene-butadiene rubbers 0.94 High styrene SBR rubbers 1.05 *According to grade

Appendix 6.2 Specific Gravities of Compounding Ingredients Ingredient Aluminium silicate Antimony trioxide Bitumen Barium sulfate Calcium silicate Carbon black Carnauba wax Calcined china clay China clay (kaolin) Cotton fibre Diethylene glycol Factice Graphite Indene-coumarone resin Iron oxide Lanolin Calcium oxide (lime) Litharge Magnesium oxide Magnesium carbonate

Specific Gravity 2.10 5.40 1.04 4.30 2.10 1.80 0.99 2.50 2.60 1.05 1.12 1.05 2.04 1.09 4.5-5.1 1.08 2.19 9.30 3.60 2.21

Rubber Analysis – Polymers, Compounds and Products

Mica Mineral oil Oleic acid Paraffin oil Paraffin wax Pine tar Rosin Silica

2.80 0.91 0.90 0.80 0.90 1.08 1.07 1.95

Stearic acid Sulfur Talc (magnesium silicate) Titanium dioxide (anatase) Titanium dioxide (rutile) Calcium carbonate Zinc oxide Zinc stearate

0.85 2.05 2.80 3.90 4.20 2.65 5.55 1.10

57

Abbreviations and Acronyms

ABBREVIATION AND ACRONYMS 6PPD AAS ATR BR CBS CHN CR CTAB DBP DCM DEHP DMTA DOP DPPD DSC Edax ELS EPA EPDM FID GC GC-MS GPC HAF HFA HPLC ICP ICT IIR IPPD IR Irganox 1010 Irganox 1076 Irganox 1098 Irganox 1330 LALLS LC LC-MS LIMA MALLS MBT MBTS MEK

58

N-1,3-dimethylbutyl-N´-phenyl-p-phenylenediamine atomic absorption spectroscopy attenuated total reflectance spectroscopy polybutadiene N-cyclohexyl-2-benzothiazole sulphenamide carbon:nitrogen:hydrogen polychloroprene cetyltrimethylammonium bromide dibutyl phthalate dichloromethane di-(2-ethyl hexyl) phthalate dynamic mechanical thermal analysis dioctyl phthalate diaryl-p-phenylene diamine differential scanning calorimetry energy dispersive analysis evaporative light scattering Environmental Protection Agency elastomeric terpolymer of ethylene, propylene and a non-conjugated diene flame ionisation detector gas chromatography gas chromatography-mass spectroscopy gel permeation chromatography high abrasion furnace higher fatty acids high performance liquid chromatography inductively coupled plasma imaging chemiluminescence technique isobutene-isoprene rubber N-isopropyl-N´-phenyl-p-phenylenediamine infrared penta-erythrityl-tetrakis-(3,5-di-tert-butyl-4-hydroxphenyl propionate) octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate N,N′-1,6-hexamethylene-bis(3-(3, 5-tert-butyl-4-hydroxyphenol)propanamide) 1,3,5-tris(3,5-ditert.butyl-4-hydroxybenzyl)mesitylen low angle laser light scattering Lab Connections liquid chromatography-mass spectroscopy laser induced mass analysis multi-angle laser light scattering 2-mercaptobenzothiazole 2-2´-dibenzothiazyl disulfide methyl ethyl ketone

Abbreviations and Acronyms

Mn MSD MT Mw Mz NBR NIH NIR NIST NMR NPD NR NVA OVA Perkadox 14/40 pphr PVC PVI RI RIC SAF SBR SEM SIMS SRF T15 TAC TAIC TEM Tg TGA THF TLC TMA TMQ TMTD UV VFA XPS XRF ZMBT ZMDC ZOV ZST

number average molecular weight mass selective detector medium thermal weight average molecular weight z average molecular weight nitrile rubber National Institute of Health nitrile-isoprene National Institute of Standards and Technology (USA) nuclear magnetic resonance nitrogen phosphorus detector natural rubber non-volatile acids organic vapour analyser di-(2-t-butylperoxyisopropyl)benzene parts per hundred of rubber polyvinyl chloride pre-vulcanisation inhibitor refractive index reconstructive ion chromatogram super abrasion furnace styrene-butadiene rubber scanning electron microscopy secondary ion mass spectrometry semireinforcing furnace the time taken for 15% of the weight of carbon black to oxidise triallyl cyanurate triallyl isocyanurate transmission electron microscopy glass transition temperature thermogravimetric analysis tetrahydrofuran thin layer chromatography thermal mechanical analysis poly-2,2,4-trimethyl-1,2-dihydroquinoline tetramethyl thiuram disulphide ultraviolet volatile fatty acid number x-ray photoelectron spectroscopy x-ray fluorescence spectroscopy zinc mercaptobenzthiazole zinc dimethyl dithiocarbamate zinc oxide viscosity zinc stability time

59

Abbreviations and Acronyms

60

References and Abstracts

References from the Rapra Abstracts Database Item 1 Polymer Degradation and Stability 70, No.1, 2000, p.31-7 QUANTIFYING RUBBER DEGRADATION USING NMR Somers A E; Bastow T J; Burgar M I; Forsyth M; Hill A J Monash,University; CSIRO Samples from a NR tank lining which had been exposed to chemical attack at elevated temperatures were studied using carbon-13 high-resolution NMR with crosspolarisation and magic angle spinning. The proton NMR transverse relaxation times were also obtained. As the level of degradation increased, the proton NMR transverse relaxation time decreased. The carbon-13 spectra indicated decreased mobility with increasing degradation and the presence of degradation products. Lower powered NMR equipment was used to measure proton transverse relaxation times were obtained for a) industrial NR samples cured using a semi-efficient vulcanisation cure system, plus additional free sulphur ranging from 0 to 3.5 phr, and b) a single composition set of industrial NR samples which were thermally aged at 100C for 0-240 h. The study showed that the simpler method was also sensitive to structural and mechanical property changes in the rubber. These techniques could lead to nondestructive testing of rubber articles in the field. 17 refs. AUSTRALIA

Accession no.819224 Item 2 Journal of Applied Polymer Science 80, No.12, 20th June 2001, p.2292-9 COMPARISON OF TETRAETHYL- AND TETRAMETHYLTHIURAM DISULFIDE VULCANIZATION. I. REACTIONS IN THE ABSENCE OF RUBBER Gradwell M H S; Grooff D Port Elizabeth,University The reactions of tetraethylthiuram di- and monosulphide (TETD and TETM, respectively) were investigated in the absence of rubber and compared with those reported previously for tetramethylthiuram compounds. The reactions of TETM, TETD and zinc diethyldithiocarbamic acid with zinc oxide and sulphur were investigated by DSC and the reaction products analysed by highperformance liquid chromatography. TETM was shown to be more stable at vulcanisation temps. but also less reactive with sulphur than tetramethylthiuram disulphide(TMTD). The reactions of TETD were very similar to those of TMTD, the TETD reacting more slowly than the TMTD to form analogous products. In the presence of zinc oxide, the formation of the zinc compound of TETD occurred readily. TMTD did not react

© Copyright 2001 Rapra Technology Limited

readily with zinc oxide. The reaction of TETD with sulphur led to the formation of polysulphidic accelerator species, although the concentrations formed in the absence of rubber were significantly lower than that formed by the corresponding TMTD system. 23 refs. SOUTH AFRICA

Accession no.817865 Item 3 Polymers & Polymer Composites 9, No.4, 2001, p.275-82 METALLIC METHACRYLATE AS A REACTIVE FILLER TO REINFORCE ETHYLENEPROPYLENE-DIENE RUBBER Peng Z; Zhang Y; Liang X; Zhang Y Shanghai,Jiao Tong University Non-polar EPDM was reinforced by the addition of polar metal salts of methacrylic acid at a high level, followed by peroxide curing. Mechanical properties and crosslink density of the vulcanisates were investigated. Wide-angle X-ray diffraction and FTIR were used to analyse the reactivity of zinc dimethacrylate (ZDMA) in EPDM compounds pre- and post-vulcanisation. It was found that ZDMA or magnesium dimethacrylate can greatly improve the hardness and tensile strength of the vulcanisates whilst retaining a high elongation at break, and that it acts as a reactive filler in the EPDM matrix during peroxide curing. Crosslink density was determined by equilibrium swelling. Covalent crosslinks and ionic crosslinks were distinguished by acidolysis treatment. Ionic crosslinks were improved by increasing the amount of ZDMA, and the relationship between mechanical properties and crosslink density are claimed to indicate that the tensile strength of the vulcanisate is principally dependent on ionic crosslink density. 19 refs. CHINA

Accession no.817546 Item 4 Nippon Gomu Kyokaishi 73, No.12, 2000, p.627-33 Japanese PHYSICAL PROPERTIES OF HIGH-PURITY NATURAL RUBBER Kawabara S; Eng A H A review is presented of research before 1990 into the density and thermal expansion, glass transition temperature, melting point and crystallinity of high-purity natural rubber, and of later investigation of the structure of natural rubber and its non-rubber components, the crystallisation behaviour and green strength. 47 refs. Accession no.816514

61

References and Abstracts

Item 5 Journal of Rubber Research 4, No.1, 1st Quarter, 2001, p.44-55 CURE CHARACTERISTICS AND MECHANICAL PROPERTIES OF VULCANISED NATURAL RUBBER BY USING A NEW BINARY ACCELERATOR SYSTEM Aprem A S; Joseph K; Mathew G; Thomas S Mahatma Gandhi,University Details are given of the vulcanisation of NR using the binary accelerator system of phenyldithiobiuret/ morpholinothio benzothiazole sulphenamide. Mechanical properties are discussed and correlated with network characteristics of the vulcanisates. Chemical characterisation was undertaken using swelling measurements. Crosslink density was compared to that obtained by stress-strain measurements. 17 refs. INDIA

Accession no.815590 Item 6 Journal of Rubber Research 4, No.1, 1st Quarter, 2001, p.1-10 DEPOLYMERISATION OF HIGHLY PURIFIED NATURAL RUBBER. I. METAL-CATALYSED OXIDATION OF DEPROTEINISED NATURAL RUBBER Sakdapipanich J T; Kowitteerawut T; Kawahara S; Tanaka Y Bangkok,Mahidol University; Nagaoka,Technological University An attempt was made to establish a method to prepare liquid rubber by chain scission of highly-purified NR using UV-irradiation and catalytic thermal degradation. The NRs used for this study were both in the latex and solution forms. Structural characterisation was undertaken using FTIR and NMR analysis. 11 refs. JAPAN; THAILAND

the factory floor. Although its feasibility for use in product and quality control of elastomers is demonstrated, a drawback to its use is the duration of the measurement times, which may be shortened, it is claimed, by a larger sensitive volume and an adapted coil geometry to extend its range of applications. 32 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.815362 Item 8 Kautchuk und Gummi Kunststoffe 54, No.3, 2001, p.122-6 ELECTROCHEMICAL EVIDENCE OF TRANSITORY IONIC SPECIES IN THE VULCANIZATION OF NATURAL RUBBER WITH SULFUR. 2MERCAPTOBENZOTHIAZOLE AND ZINC OXIDE: THE ACTIVATOR EFFECT OF STEARIC ACID Hummel K; Rodriguez F J S Graz,Technische Universitat Continuous low level current measurements are used to investigate the vulcanisation of natural rubber with sulphur, 2-mercaptobenzothiazole and zinc oxide in the presence and absence of stearic acid. At elevated temperatures, the mixtures showed increased conductivity, which was attributed to the presence of ions. Current curve maxima, characteristic of transitory ionic species are detected. Possible ions are discussed in connection with references in the literature. For the mixture NR/S/MBT/ ZnO/StAc, the comparison with the rheometer measurements demonstrates a relationship between the formation of ionic intermediates and crosslinking of the polymer. The suitability of the electrochemical method for the investigation of ionic species in crosslinking reactions is demonstrated. 20 refs. AUSTRIA; EUROPEAN UNION; WESTERN EUROPE

Accession no.815292

Accession no.815585 Item 7 Kautchuk und Gummi Kunststoffe 54, No.4, 2001, p.188-90 NMR FOR PRODUCT AND QUALITY CONTROL OF ELASTOMERS Blumich B Aachen,University of Technology The potential for the use of nuclear magnetic resonance techniques as a method of product and quality control in elastomers, is discussed. A review is presented of industrial applications of magnetic resonance techniques in environments more demanding than those of a clean laboratory, using the NMR-Mouse. The NMR-Mouse is used to determine the different properties of soft matter products, performing imaging with unilateral NMR on

62

Item 9 Polymer 42, No.14, 2001, p.6259-70 ATOMIC FORCE MICROSCOPY INVESTIGATION OF FILLED ELASTOMERS AND COMPARISON WITH TRANSMISSION ELECTRON MICROSCOPY - APPLICATION TO SILICA-FILLED SILICONE ELASTOMERS Clement F; Lapra A; Bokobza L; Monnerie L; Menez P Laboratoire de Physicochemie Struct.et Macromol.; Rhodia Recherches Silica-filled silicone elastomers were subjected to tapping mode atomic force microscopy (AFM), using phase images to give good contrast between the silicon matrix and silica structures, and to permit a study of silica dispersions, and with due attention to the fact phase

© Copyright 2001 Rapra Technology Limited

References and Abstracts

contrast is sensitive to various experimental factors which have an effect on tip-sample interactions. The phase contrast was studied as a function of cantilever oscillation free amplitude, the setpoint ratio, the cantilever stiffness, and the sample modulus. The main parameter controlling the tip-sample force and thus the phase contrast was the setpoint ratio. Comparison of the results with transmission electron microscope tests shown that tapping mode AFM with phase imaging is an easy and powerful method for characterising the silica dispersion in a silicone matrix. The method could be applied to obtaining better understanding of filled rubber reinforcement. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.815179

to increase in the silica/SBR vulcanisate above 400K and that the introduction of open spaces was suppressed in the carbon black/SBR vulcanisate, even at 420K. 16 refs. JAPAN

Accession no.813904 Item 12 China Rubber Industry 48, No.4, 2001, p.233-4 Chinese DETERMINATION OF WATER-SOLUBLE ZINC IN VULCANISATE BY ATOMIC ABSORPTION SPECTROMETRY Ai Dan-yang; Tuo Rui CHINA

Accession no.813848 Item 10 Polymer 42, No.12, 2001, p.5415-23 FILLED ELASTOMERS; A NEW APPROACH BASED ON MEASUREMENTS OF CHAIN ORIENTATION Bokobza L ESPCI Rubber compounds based on SBR and filled with silica at two different levels (27 and 55 parts per hundred rubber), both with and without silane coupling agents, were studied using infrared and birefringence techniques to determine orientational behaviour of the filled polymer network. Correlation of the results with equilibrium stressstrain measurements and swelling in cyclohexane was carried out with good correlation reported between swelling and birefringence measurements. 26 refs EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.814062 Item 11 Journal of Polymer Science: Polymer Physics Edition 39, No.8, 15th April 2001, p.835-42 OPEN SPACES AND MOLECULAR MOTIONS IN CARBON BLACK- AND SILICA-LOADED SBR INVESTIGATED USING POSITRON ANNIHILATION Uedono A; Fukui S; Muramatsu M; Ubukata T; Kimura S; Tanigawa S Tsukuba,University; JSR Corp. Measurements were made of the lifetime spectra of positrons for carbon black- and silica-filled SBR vulcanisates and unfilled SBR vulcanisates. The temperature dependences of the lifetime of orthopositronium and its intensity were determined and the parameters corresponding to the annihilation of orthopositronium in SBR derived using the results obtained for carbon black and silica. It was found that the density of open spaces was reduced by filler addition but began

© Copyright 2001 Rapra Technology Limited

Item 13 China Rubber Industry 48, No.3, 2001, p.170-3 Chinese STUDY ON POTENTIOMETRIC TITRATION END FOR DETERMINATION OF SOAP CONTENT IN SBR Zhao Qing; Guo Hong-da CHINA

Accession no.813833 Item 14 China Rubber Industry 48, No.3, 2001, p.149-53 Chinese QUALITY ANALYSIS OF SBR Fu Yan-jie; Zhao Zhen-hua Accession no.813828 Item 15 Journal of Applied Polymer Science 80, No.14, 28th June 2001, p.2737-45 POLYBLEND SYSTEMS OF POLYURETHANE (AU) AND ETHYLENE ACRYLIC ELASTOMER (VAMAC) USING THE SULFUR CURE SYSTEMS Khatua B B; Das C K Indian Institute of Technology Blends of a polyurethane (PU) elastomer and an ethylene acrylic elastomer were prepared using three different techniques: masterbatch, preblending, and preheating preblending. The processability and ageing of the PU elastomer were enhanced by blending with the acrylic elastomer. Infrared spectroscopy of the 50:50 blend indicated interchain crosslinking on heat treatment, which also enhanced the thermal stability. Crosslinking also affected the solvent extraction of a single phase. 18 refs. INDIA

Accession no.813713

63

References and Abstracts

Item 16 International Polymer Science and Technology 28, No.2, 2001, p.T/24-6 NEW METHOD FOR STUDYING THE PENETRATION OF THE SOLVENT INTO THE FREE VOLUME OF VULCANISED RUBBERS DURING SWELLING Kucherskii A M NIIEMI Open Joint Stock Co. A hydrostatic (gravimetric) method is proposed for the study of the nature of free volume with respect to vulcanised rubbers during swelling by solvent penetration. Unfilled and carbon black filled vulcanisates based on non-polar butadiene-methylstyrene rubber and polar butadiene-acrylonitrile rubbers were investigated, with swelling carried out in dibutyl sebacinate and dibutyl phthalate, and in a 7:3 isooctane-toluene mixture simulating motor fuel. It is assumed that the reduction in the volume of the system is connected with penetration of the solvent into the free volume of the rubber phase, and equations are presented which are used to determine the percentage of the volume of the specimen that is occupied by solvent in the free volume. 10 refs. (Translated from Kauchuk i Rezina, No.4, 2000, p.20) RUSSIA

Accession no.811255 Item 17 Journal of Polymer Science: Polymer Physics Edition 39, No.7, 1st April 2001, p.811-7 STRAIN INDUCED CRYSTALLISATION AND STRENGTH OF ELASTOMERS. I. CIS-1,4POLYBUTADIENE Gent A N; Zhang L Q Akron,University; Beijing,University of Chemical Technology Crosslinked samples of cis-1,4-polybutadiene (BR) are crystallised at low temperatures and then slowly melted. From volume changes and differential scanning calorimetry measurements, the degree of crystallisation in the unstrained state is estimated to be about 20%, much lower than for NR. Crystallisation and melting are followed in stretched samples by corresponding changes in tensile stress. Crystallisation is faster at higher strains, and the melting temperature is raised significantly on stretching but less than for NR, and the decrease in stress on crystallising is smaller. Measurements of tensile strength are made over a wide temperature range and show a marked drop with heating to temperatures of 40-60 deg.C, falling to values of only 1-2 MPa. A similar drop in strength occurs in NR vulcanisates at high temperatures and is attributed to failure to crystallise on stretching. At ambient temperatures, where strain-induced crystallisation occurs, the strength of BR samples is only about one-half of that of similar NR materials. This is attributed to less strain-induced crystallinity in BR (verified by X-ray studies), paralleling the lower amount

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developed at low temperatures. It is speculated that the higher density of molecular entanglements in BR than in NR prevents BR from crystallising to the same degree as NR. 13 refs. CHINA; USA

Accession no.811200 Item 18 Polymer 42,No.9, 2001,p.4393-9 FRACTOGRAPHIC STUDY OF EPOXY RESIN USING GROUND TYRE RUBBER Kaynak C; Sipahi-Saglam E; Akovali G Ankara,Middle East Technical University In a fractographic study of epoxy resin toughened with scrap car tyre regrinds five different surface treatment methods were used to improve the compatability at the rubber particle/epoxy matrix interface, i.e. treatment with an oxygen plasma, two silane coupling agents, acrylic acid, and acrylic acid/benzoyl peroxide mixture. After surface treatment, the rubber parts of the ground scrap tyres, size range 355-50 micron, were mixed with the epoxy resin, and the mixture was poured into moulds to obtain fracture toughness test specimens. After curing, these specimens were subjected to plane strain fracture toughness tests, and the fracture faces were examined under a scanning electron microscope. The fractographic tests showed that the improved fracture toughness values obtained were the result of the improved interface, leading to crack deflection as the principal toughening mechanism. Some shear deformation and debonding initiated at the interface was observed. 9 refs. TURKEY

Accession no.811126 Item 19 Polymer International 50, No.4, April 2001, p.387-94 HIGH-RESOLUTION SOLID-STATE NMR INVESTIGATION OF THE FILLER-RUBBER INTERACTION. II. HIGH-SPEED (1H) MAGICANGLE SPINNING NMR SPECTROSCOPY IN CARBON-BLACK-FILLED POLYBUTADIENE Mansencal R; Haidar B; Vidal A; Delmotte L; Chezeau J M Institut de Chimie des Surfaces et Interfaces; Mulhouse,Ecole Nationale Superieure de Chimie The behaviour of elastomeric chains (polybutadienes of identical molec.wt. but different microstructures) in the close vicinity of carbon black surfaces was investigated in order to gain a better understanding of the structure and properties of interphases. Elastomer-filler interactions were assessed by study of the thermal properties and NMR relaxation characteristics of the corresponding materials. Three series of samples were compared, i.e. pure polymers, raw polymer-filler blends (filler loading ratio

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References and Abstracts

50 phr) and solvent-extracted blends. While DSC indicated the existence of an elastomer fraction which was not detected as undergoing the Tg, i.e. was strongly immobilised, proton high-resolution high-speed magicangle spinning solid-state NMR provided information on the effect exerted by polymer-filler interactions on the mobility of the various constitutive species of the macromolecular backbone. A systematic study of the evolution of the spectral lines yielded by the samples indicated that 1,2-polybutadiene moieties had a particular affinity towards the carbon black surface which suggested the occurrence of specific interactions at the elastomerfiller interface. 38 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.810585 Item 20 Rubber Chemistry and Technology 73, No.5, Nov./Dec.2000, p.926-36 TEM OBSERVATION OF NATURAL RUBBER THIN FILMS CRYSTALLIZED UNDER MOLECULAR ORIENTATION Shimizu T; Tosaka M; Tsuji M; Kohjiya S Toyo Tire & Rubber Co.Ltd.; Kyoto,University The morphology of NR thin films crystallised under molecular orientation was examined by TEM. A thin film of NR was prepared by casting its solution onto the water surface and prestretched up to a desired amount of strain. Each of the specimens was introduced into a TEM column and isothermally crystallised at -25C with a cryo-transfer specimen-holder. Morphological observations in brightand dark-field imaging modes revealed directly that the length of the lamellae, which were oriented perpendicular to the stretching direction, decreased with increasing strain. The results appeared to be related to the population density of gamma-filaments generated only by prestretching. Time-resolved bright-field observations by in situ TEM of the thin film prestretched up to a strain of 200% indicated that gamma-filaments were formed immediately by prestretching and then the lamellae were nucleated on the gamma-filaments at -25C. 27 refs. (ACS Rubber Division, Fall Meeting, Orlando, Florida, USA, Sept.1999) JAPAN

Accession no.810527 Item 21 Rubber Chemistry and Technology 73, No.5, Nov./Dec.2000, p.912-25 USE OF ATOMIC FORCE MICROSCOPE AS A NANOINDENTER TO CHARACTERIZE ELASTOMERS Mareanukroh M; Eby R K; Scavuzzo R J; Hamed G R; Preuschen J Akron,University; Max-Planck-Institut fuer Polymerforschung

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Atomic force microscopy was used in the force mode as a nanoindenter for determining the crosslink density and modulus of rubber on a fine scale. The force-distance curves obtained as the sample was moved against the tip could provide information about mechanical properties of the sample. The technique for this purpose was established. Several instruments and technical difficulties encountered during the development of the technique were identified and solved. The difficulties included surface roughness, thickness variation of the sample, hysteresis of the scanner, determining the stiffness of the cantilever, determining the geometry of the tip, converting the sensor output to force and determining the penetration depth of the tip. The determination of the effective tip geometry required use of a calibration material. Force-distance measurements were made on a series of SBR with different crosslink densities. 16 refs. USA

Accession no.810526 Item 22 Rubber Chemistry and Technology 73, No.5, Nov./Dec.2000, p.847-63 INELASTIC NEUTRON SCATTERING FROM FILLED ELASTOMERS Nakatani A I; Ivkov R; Papanek P; Yang H; Gerspacher M US,National Inst.of Standards & Technology; Pennsylvania,University; Richardson S.,Carbon Co. An overview of inelastic neutron scattering techniques is presented. Neutron filter analyser and time-of-flight spectroscopy methods were used to characterise the local dynamics of polymers in the presence and absence of fillers. Particular attention was paid to the comparison between bound rubber attached to the filler surface and the pure, unbound rubber. A commercial synthetic polyisoprene containing about 100% cis-1,4-isomers was compounded with three different carbon blacks, N299, G299 (graphitised N299) and N762. Soxhlet extraction on each of the samples was performed so that corresponding samples containing purely bound rubber with filler were obtained. The filter analyser and timeof-flight spectra showed distinct differences between the bound and pure rubber as well as differences based on carbon black type. Correlation of the spectral differences to the type of carbon black and initial concentration of carbon black is discussed. 35 refs. USA

Accession no.810522 Item 23 Journal of Coatings Technology 73, No.913, Feb.2001, p.115-24 FREE VOLUME DISTRIBUTION DURING CONSOLIDATION AND COALESCENCE OF LATEX FILMS

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References and Abstracts

Hill A J; Tant M R; McGill R L; Shang P P; Stocki R R; Murray D L; Cloyd J D Eastman Chemical Co. The effect of molecular architecture on free volume distribution is studied during consolidation and coalescence of aqueous latex emulsions. Two series of model emulsion polymers, isobutyl methacrylate (i-BMA) and normal-butyl methacrylate (n-BMA) dispersions with varying level of trimethylolpropanetriacrylate (TMPTA) crosslinker, are studied. Coatings are characterised by positron annihilation lifetime spectroscopy and atomic force microscopy. Formation of coherent brittle films without significant interdiffusion is achieved by consolidation below the glass transition temperature (Tg). Consolidation, or ordering/compaction of films following water evaporation at temperatures below the MFFT, results in a decrease in the relative free volume element size, T3, as measured by PALS. An increase in the characteristic relaxation time for the consolidation process is evident as TMPTA levels and corresponding gel fraction increase. Consolidation below Tg is accompanied by physical ageing. Coalescence and interdiffusion are achieved by annealing films at or above Tg. Annealed coatings show a decrease in Tg and an increase in PALS free volume attributed to erasure of physical ageing in combination with the action of the surfactant (sodium dodecyl sulphate) as a plasticiser. 43 refs. USA

Accession no.809442 Item 24 Polimeros: Ciencia e Tecnologia 10, No.4, Oct./Dec.2000, p.230-7 Portuguese POLYMERIZATION OF BUTADIENE BY THE CATALYST SYSTEM TITANIUM TETRACHLORIDE/ TRIISOBUTYLALUMINIUM/IODINE Pires N M; Costa M A S; Coutinho F M B Petroflex Industria e Comercio SA; Rio de Janeiro,University A modified Ziegler-Natta catalytic system consisting of titanium tetrachloride/triisobutylaluminium/iodine was used to produce BR with high content of 1,4-cis repeating units. The influence of the catalytic system composition and temperature on the catalyst activity, molecular weight and microstructure of the BR was studied. Polymers were characterised by IR spectroscopy and size exclusion chromatography. 31 refs. BRAZIL

Accession no.808132 Item 25 Journal of Polymer Science: Polymer Physics Edition 39, No.4, 15th Feb.2001, p.439-45

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FILLER-POLYMER INTERACTIONS IN BOTH SILICA AND CARBON BLACK-FILLED STYRENE-BUTADIENE RUBBER COMPOUNDS Sung-Seen Choi Kumho R & D Center Filler-polymer interactions in both silica- and carbon black-filled SBR compounds were studied by analysing microstructures of the bound rubbers with pyrolysis gas chromatography. Differences in the filler-polymer interactions of the styrene, cis-1,4-, trans-1,4- and 1,2units were investigated. The filler-polymer interactions of the butadiene units were found to be stronger than that of the styrene unit. The interactions of the cis-1,4- and trans-1,4-units were stronger with carbon black than with silica, whereas the 1,2-unit interacted more strongly with silica than with carbon black. 23 refs. KOREA

Accession no.807383 Item 26 Macromolecular Chemistry & Physics 202, No.1, 24th Jan.2001, p.73-81 STRUCTURE OF POLYBUTADIENES SYNTHESISED WITH A NEW CATALYST SYSTEM. II. BLENDS OF TRANS- AND CIS-1,4POLYBUTADIENE Antipov E M; Mushina E A; Stamm M; Fischer E W Topchiev,Institute of Petrochemical Synthesis; Dresden,Institute of Polymer Research; Max-PlanckInstitut fuer Polymerforschung The structure, composition and temp. behaviour of polybutadienes prepared with binuclear metal complex catalysts (containing Ti-Mg and Cr-containing compounds) immobilised on a solid carrier were investigated by DSC, IR spectroscopy and X-ray scattering. Polybutadienes of nascent structure were blends of trans-1,4- and cis-1,4homopolymers, whereas 1,2-units were randomly distributed in both macromolecules. The blends exhibited two-step melting characteristics for the crystalline trans1,4-polybutadiene, i.e. the low temp. transition from the monoclinic crystal form to the pseudohexagonal mesophase and the high temp. transition from mesophase to the melt. A bimodal character of the endothermic maximum in DSC traces was observed for the former transition. It was also shown that the nascent blend treated by hot toluene possessed a three-phase structure and contained, apart from the well-known trans-1,4-polybutadiene crystalline and amorphous phases, an additional phase component of unknown structure. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; RUSSIA; WESTERN EUROPE

Accession no.807342 Item 27 Polymer 42, No.8, 2001, p.3633-9

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References and Abstracts

DYNAMIC-MECHANICAL AND DIFFERENTIAL SCANNING CALORIMETRY MEASUREMENTS ON CROSSLINKED POLY(ESTER-SILOXANE)URETHANES Ioan S; Grigorescu G; Stanciu A Petru Poni,Institute of Macromolecular Chemistry

FOR THE CHARACTERIZATION OF ORGANICALLY MODIFIED SILICATES Babonneau F; Gualandris V; Maquet J; Massiot D; Janicke M T; Chmelka B F Paris,Universite Pierre et Marie Curie; CNRS; California,University at Santa Barbara

Crosslinked poly(ester-siloxane)-urethanes containing hard and soft segments were synthesised by a single step melting/polyaddition reaction and analysed by means of DMA and differential scanning calorimetry. The soft segments were based on poly(ethylene glycol adipate)diol or poly(diethylene glycol adipate)diol, alpha,omegapoly(dimethylsiloxane)diol and/or polybutadiene diol and the hard segments were based on diglycerin maleate tetrol and MDI or TDI. The effects of frequency and soft and hard segment structure on the tensile properties of the elastomers were examined. It is shown that the thermal curves are significantly affected by both the soft and hard segment structures of the elastomers. 39 refs.

The use of two-dimensional solid-state NMR correlation techniques to probe the chemical homogeneity of organically modified silicate networks was studied. Specifically, silicon-29(proton) heteronuclear correlation NMR experiments revealed the spatial proximity of the two types of silicon units present in a gel obtained from co-hydrolysis of methyldiethoxysilane and triethoxysilane. Similar information was also obtained by using two-dimensional proton homonuclear correlation NMR spectroscopy. Such experiments were only possible by combining the use of high magnetic field (14.10 T) with fast magic angle spinning rate (30 kHz). 10 refs. (10th International Workshop on Glass and Ceramics, Hybrids and Nanocomposites from Gels, ‘Sol-Gel ‘99’, Yokohama, Japan, Sept.1999)

EASTERN EUROPE; RUMANIA

Accession no.806160

EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; USA; WESTERN EUROPE

Item 28 Journal of Applied Polymer Science 79, No.7, 14th Feb. 2001, p.1309-16 VULCANISATION OF CHLOROBUTYL RUBBER. III. REACTION MECHANISMS IN COMPOUNDS CONTAINING COMBINATIONS OF ZINC DIMETHYLDITHIOCARBAMATE, TETRAMETHYLTHIURAM DISULPHIDE, SULPHUR, AND ZNO Hendrikse K G; McGill W J Port Elizabeth,University The sulphur vulcanisation of butyl rubber and chlorobutyl rubber accelerated with TMTD was investigated in the absence of ZnO and the results compared for the different rubbers. Extractable reaction by-products present at different stages of the vulcanisation reaction were analysed using HPLC and atomic absorption spectroscopy and changes taking place during the vulcanisation of chlorobutyl rubber with zinc dimethyldithiocarbamate and TMTD/sulphur/zinc oxide formulations examined. A mechanism, which accounts for dehydrochlorination and crosslinking in the presence of zinc dimethyldithiocarbamate was developed and the influence of accelerated sulphur and chlorine abstraction reactions on vulcanisation assessed. 27 refs. SOUTH AFRICA

Accession no.805895 Item 29 Journal of Sol-Gel Science and Technology 19, Nos.1-3, Dec.2000, p.113-7 NEWLY APPLIED TWO-DIMENSIONAL SOLIDSTATE NMR CORRELATION TECHNIQUES

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Accession no.805098 Item 30 Journal of Rubber Research 3, No.4, 4th Quarter, 2000, p.232-47 STIMULATOR PROTEIN OF RUBBER BIOSYNTHESIS FROM HEVEA BRASILIENSIS LATEX Yusof F; Chow K-S; Ward M A; Walker J M Rubber Research Institute of Malaysia; Hertfordshire,University; Glaxo-Wellcome A rubber biosynthesis stimulator protein from the C-serum of Hevea brasiliensis latex was purified and characterised. Molecular weights and amino acid sequencing of the peptide fragments obtained from trypsin digestion were determined. DNA cloning is also presented. 12 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; MALAYSIA; UK; WESTERN EUROPE

Accession no.804555 Item 31 Revue Generale des Caoutchoucs et Plastiques 77, No.786, May 2000, p.52-8 French VULCANISATION: IDENTIFICATION AND MECHANISMS OF REACTION Plessier L; Lemaitre T; Triquenaux O; Gomez E Ifoca; LRCCP Results are presented of a study in which the sulphur vulcanisation of polyisoprene was carried out at 150C and gas chromatography/mass spectrometry and HPLC were used to determine the chemical nature of

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References and Abstracts

intermediates and accelerator residues formed during the vulcanisation reaction. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.803898 Item 32 ACS Polymeric Materials: Science and Engineering. Fall Meeting 2000. Volume 83. Washington, D.C., 20th-24th Aug.2000, p.426-7 DIFFUSION OF ALCOHOLS THROUGH SULPHONATED PS/PIB/PS BLOCK COPOLYMERS USING FT-IR-ATR Napadensky G; Sloan J M; Tan N B; Crawford D; Mountz D A; Mauritz K A US,Army Research Laboratory; Southern Mississippi,University (ACS,Div.of Polymeric Materials Science & Engng.) PS-polyisobutylene-PS (PS-PIB-PS) block copolymers are known to have excellent barrier properties to hazardous vapours and liquids. However, when these block copolymers are sulphonated, water and small polar molecules are allowed to be transported through the polymer film. In some instances, this could be beneficial and allow the film to be used as a separation membrane. The fundamental physical property required to design and optimise polymers used as barrier and membranes is the diffusion coefficient. For many years, polymer/penetrant mutual diffusion coefficients have been measured by the dip and weigh methods, GC permeation measurements and vapour sorption experiments. The transport properties for a series of alcohols through a sulphonated PS/PIB/PS block co-polymer using FT-IR to monitor the transport process are reported. FT-IR methods offer identification of specific chemical interactions occurring between the polymer and diffusing molecules. A basic FT-IR-ATR Fickian diffusion model is applied to the resultant data. 6 refs. USA

Accession no.802690 Item 33 Polymer International 49, No.12, Dec.2000, p.1658-64 SYNTHESIS AND CHARACTERISATION OF A NOVEL TEREPHTHALATE-BRIDGED LADDERLIKE POLYMETHYLSILOXANE Liu C; Liu Z; Liu Y; Xie P; Zhang R Chinese Academy of Sciences; China Petrochemical Corp. A novel soluble terephthalate-bridged ladder-like polymethylsiloxane is successfully synthesised by stepwise coupling polymerisation in three steps, including hydrosilylation coupling, hydrolysis and polycondensation. The bis(3-methyldichlorosilylpropyl) terephthalate monomer is first synthesised by hydrosilylation reaction in the presence of dicyclopentadienylplatinum(II) chloride

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(Cp2PtCl2) catalyst. The structures of the monomer and the polymer are characterised by FTIR, 1H NMR, 13C NMR and 29Si NMR spectroscopy, mass spectrometry, Xray diffraction, differential scanning calorimetry, vapour pressure osmometry and gel permeation chromatography. Characterisation data indicate that the synthesised polymer possesses an ordered ladder-like structure. 22 refs. CHINA

Accession no.802572 Item 34 Polymer International 49, No.12, Dec.2000, p.1653-7 IONIC ELASTOMER BASED ON CARBOXYLATED NITRILE RUBBER: INFRARED SPECTRAL ANALYSIS Mandal U K GGS Indraprastha University Carboxylated nitrile rubber (XNBR) neutralised by metal oxide forms an ionic elastomer (ionomer) due to formation of ionic clusters by the metal carboxylated salt. Cluster formation in carboxylated nitrile rubber by metal oxide, mainly zinc oxide (ZnO), is studied by IR analyses. Two modes of plasticisation, i.e. plasticisation of the hydrocarbon-rich phase and plasticisation of the ionic domains (hard phase), are also analysed by IR studies. Results reveal that the cluster formation stabilises at higher loading of metal oxide with hexacoordinate salt formation and depends on the type of metal oxide. Spectral studies also reveal that a non-polar plasticiser such as dioctyl phthalate does not affect the characteristic bands of ionic cluster, but polar plasticisers such as dimethylsulphoxide and ammonia solvate the ionic cluster, causing the disappearance of the band corresponding to the hexacoordinated carboxylate salt. IR spectral analysis of the ionomer based on XNBR further confirms earlier claims that the profound change in physical properties of the polymer is due to the presence of physical crosslinks generated by ionic clusters. 19 refs. INDIA

Accession no.802571 Item 35 China Rubber Industry 47, No.12, 2000, p.707-11 Chinese INFLUENCE OF 1,2-PBR AND BR ON CURING BEHAVIOUR AND PHYSICAL PROPERTIES OF EPDM Yang J; Chen Z-H; Lu X-J; Wang D-Z Guangzhou,South China University of Technology Blends of 1,2 butyl rubber and polybutadiene with EPDM rubbers with either peroxide or sulphur cure systems were examined for their curing behaviour, crosslink density and physical property characterisation. It was concluded that

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References and Abstracts

the better cure system for the 1,2 PBR/EPDM blend was the peroxide system. 5 refs. CHINA

Accession no.801439 Item 36 West Conshohocken, Pa., 2000, pp.5. NALOAN ASTM D 5670-.TEST METHOD FOR RUBBER DETERMINATION OF RESIDUAL UNSATURATION IN HYDROGENATED NITRILE RUBBER (HNBR) BY INFRARED SPECTROPHOTOMETRY American Society for Testing & Materials ASTM D 5670-

MICRO STRUCTURAL ANALYSIS OF CARBON GEL Kiuchi Y; Ito M The mechanism of formation and the structure of bound rubber is investigated. Rubber composites produced with different combinations of rubber and filler were studied on the basis of the bound rubber yield and its structure as inferred from NMR data. Results indicated that the chemical interaction at the rubber-filler interface had a great effect on the formation of bound rubber. Polyisoprene composites filled with commercial carbon black and oxidation-treated carbon black were used to investigate the mechanism of formation and structure of the bound rubber in relation to the chemical structure of the carbon black surface. 19 refs. (Translated from Nippon Gomu Kyokaishi, No.10, 1999, p.599)

Version 95 (R2000). Photocopies and loans of this document are not available from Rapra.

JAPAN

USA

Accession no.799376

Accession no.801072 Item 37 Polymer 41, No.9, 2000, p.3405-10 COMPARISON OF RESIDUAL DIPOLAR INTERACTIONS IN UNCROSSLINKED AND CROSSLINKED NATURAL RUBBER BY HIGHRESOLUTION SOLID-STATE NMR SPECTROSCOPY Eulry V; Tekely P; Humbert F; Canet D; Marcilloux J Nancy,Universite Henri Poincare; Hutchinson,Centre de Recherche It is shown that local residual dipolar broadening of protons coupled to carbon-13 is a sensitive way to observe motional constraints from networks and entanglements in crosslinked and uncrosslinked rubber systems. This may be easily obtained from the indirect observation of the proton spin system through carbon-13 resonance under slow magic angle spinning conditions. The method was used to visualise the changes in the amount of physical constraints induced during the mechanical treatment that precedes the vulcanisation process. In this case two four NR samples were studied. Two samples contained curing systems, i.e. sulphur, N-cyclohexyl benzothiazole 2sulphenamide, zinc oxide and stearic acid. Mastication was in a two roll mill. It was shown that, under certain circumstances, the residual dipolar interactions in uncrosslinked NR may be roughly as important as those observed in a highly crosslinked rubber. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.799540 Item 38 International Polymer Science and Technology 27, No. 11, 2000, p.T/31-6

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Item 39 Kautchuk und Gummi Kunststoffe 53, No.12, Dec. 2000, p.711-5 TIME OF FLIGHT SIMS AS A USEFUL TECHNIQUE FOR THE STUDY OF THE INFLUENCE OF CARBON BLACK IN NATURAL RUBBER VULCANIZATION Borros S; Vidal E; Agullo N; van Ooij W J Sarria,Institut Quimic The use of TOFSIMS as a technique to analyse the carbon black surface during the squalene vulcanisation reaction is demonstrated to be a useful tool by which to follow the sulphur vulcanisation kinetics. The results obtained are shown to be in agreement with those derived using the classic techniques of HPLC and GPC. A discussion is presented of the results of the study, which demonstrate that the intermediate compounds are strongly absorbed on the carbon black surface. 12 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; USA; WESTERN EUROPE

Accession no.799300 Item 40 Rubber Chemistry and Technology 73, No.4, Sept./Oct.2000, p.731-42 NEW EMULSION SBR TECHNOLOGY: PART I. RAW POLYMER STUDY Lewandowski L; Sibbald M S; Mallamaci M P Goodyear Tire & Rubber Co. A novel emulsion styrene-butadiene rubber (ESBR) has been developed by blending different molecular weight fractions in the latex phase, followed by co-coagulation, which has some of the rheological characteristics of solution styrene-butadiene polymers. Measurement of two glass transition temperatures and observations using scanning probe microscopy indicate a two-phase co-

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References and Abstracts

continuous composition when the difference in bound styrene between the two components is greater than 18%. Thermal field flow fractionation was used to measure molecular weight distribution, as this has been found better than size exclusion chromatography for the higher molecular weight fractions. Characterisation of viscoelastic behaviour in terminal and rubbery plateau zones used time-temperature superposition, and a crossover in the ESBR blends which was not apparent in 1502 and 1712 types of ESBR was observed. (Presented as paper 11 at the Spring ACS Rubber Division Meeting (Chicago) April 13-16, 1999; revised). 22 refs. USA

Accession no.798624

or contamination. 9 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. Accession no.797699 Item 43 Kauchuk i Rezina (USSR) No.3, 2000, p.24-7 Russian DEVELOPING METHODS TO INCREASE THE BOND STRENGTH BETWEEN THE COMPONENTS OF PLIED-UP RUBBER-CORD COMPOSITES Bashchenko Yu N; Sokolova G A; Shcherbakov A B; Onishchenko Z V

Item 41 Rubber Chemistry and Technology 73, No.4, Sept./Oct.2000, p.694-705 KINETIC ANALYSIS OF THE THERMAL DEGRADATION OF PP-EPDM BLENDS Lopez-Manchado M; Torre L; Kenny J M Madrid,Instituto de Ciencia y Tec.de Polim.; Perugia,University

The effect of modifiers containing standard adhesion promoters and additives on metal cord/rubber and rubber/ rubber adhesion were studied using UV spectroscopy. 12 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. Accession no.797684

Thermogravimetric analysis (TGA) was used to develop a kinetic model of the degradation of blends of polypropylene (PP) and ethylene-propylene-diene rubber (EPDM). TGA under both static (isothermal) and dynamic (constant heating rate) conditions, with a nitrogen purge, was used with activation energies determined from the dynamic test and order of reaction from the static test. The study indicated that activation energy of the degradation process depends on the proportion of the EPDM present, but that the degradation process was a single step reaction rather than there being separate steps for the PP and EPDM components. 24 refs.

Item 44 Journal of Applied Polymer Science 78, No.8, 21st Nov.2000, p.1573-7 NEW TECHNOLOGY OF CRUMB RUBBER COMPOUNDING FOR RECYCLING OF WASTE TIRES Kim J K; Lee S H Gyeongsang,National University

EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; SPAIN; WESTERN EUROPE

Accession no.798622 Item 42 Nippon Gomu Kyokaishi 73, No.7, 2000, p.405-9 Japanese CONTINUOUS DEVULCANISATION BY SHEAR FLOW STAGE REACTION CONTROL TECHNOLOGY FOR RUBBER RECYCLING. PART X. RAPID IDENTIFICATION OF WASTE RUBBERS Murase A; Sato N A pyrolysis IR spectroscopy system using a pyrolysis probe is described for the rapid identification of waste rubbers containing a large amount of carbon black. A small area is rapidly pyrolysed using a heated probe and the gaseous products carried into an FTIR cell with nitrogen gas. It is reported that almost all types of waste rubber can be rapidly identified, despite any surface degradation

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The efficacy of polyurethane and Styrene Butadiene Rubber as binders for ground rubber prepared from waste tyres are compared to a formulation of a compound developed without binder. Without binder, the effect of both sulphur and accelerator (TMTD) content on tensile properties are studied, and also the effect of ageing on these properties. Morphological studies using scanning electron microscopy on the cured samples were carried out to determine the cause of the variation in properties. The suggested uses of the unbound product include rubber blocks, and ballast mats for railway applications. 10 refs KOREA

Accession no.796709 Item 45 Journal of Applied Polymer Science 78, No.8, 21st Nov.2000, p.1551-4 COMPARISON OF INTERMESHING ROTOR AND TRADITIONAL ROTORS OF INTERNAL MIXERS IN DISPERSING SILICA AND OTHER FILLERS Koolhiran C; White J L Akron,University,Inst.of Polym.Engineering A study of the mixing characteristics of intermeshing and tangential rotors on rubber compounds filled with silica,

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References and Abstracts

black and talc shows that the intermeshing rotors more effectively disperse and distribute the fillers and produce compounds with lower viscosity. Dispersion was assessed by studying the change in agglomerate size with mixing time using a scanning electron microscope, distributive mixing using a flow visualisation method and viscosity by measurement with a biconical rotational viscometer. 15 refs USA

Accession no.796706 Item 46 Journal of Applied Polymer Science 78, No.8, 21st Nov.2000, p.1517-20 CHARACTERISATION OF NEW LATEXTIMBER CLONES OF NATURAL RUBBER Ong E L Rubber Research Institute of Malaysia New clones of natural rubber trees, identified as the RRIM 2000 series have been developed to improve both latex yield and timber yield. The latter is important due to increasing demands for rubber wood, whilst with the former it is important that both latex and solid rubber properties are compatible with existing, widely planted, clones. It was shown that mechanical stability time of the latex is satisfactory, and dry rubber content is generally higher than existing clones. Ash content, plasticity retention index, volatile matter and nitrogen content are all within the specification for Standard Malaysian Rubber, whilst molecular weight distribution is largely unimodal. These strains of experimental tree have yet to be assessed for their performance in different climates, soil and disease environments, but the implication is that satisfactory rubber products could be produced from these clones. 2 refs MALAYSIA

Accession no.796702 Item 47 Journal of Applied Polymer Science 78, No.8, 21st Nov.2000, p.1486-94 INFLUENCE OF NONRUBBER CONSTITUENTS ON TACK OF NATURAL RUBBER, 1. AT VERY SHORT TIMES OF CONTACT (PENDULUM TEST) David M O; Nipithakul T; Nardin M; Schultz J; Suchiva K CNRS-UPR; Mahidol University A pendulum test giving a very short contact time between the sample and a glass plate was used to assess the tack energy for various peroxide cured natural rubbers, both whole and purified, with cured synthetic polyisoprene used as a reference. It was shown that the tack energy of the whole natural rubber was lowest, whilst polyisoprene and lipid-free natural rubber was the highest. Tack energy always increased with contact time. Neither surface

© Copyright 2001 Rapra Technology Limited

energy nor bulk viscoelastic properties of the cured materials could explain the differences observed, but chemical analysis of the cured rubber surface indicated differences which appeared to explain differences in the measurements. Whether this is due to the mechanical properties of the surface layer which are different with different compositions, or whether there is some transfer mechanism between the surface layer of rubber and the glass, is subject to further study. 21 refs EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; THAILAND; WESTERN EUROPE

Accession no.796698 Item 48 Journal of Applied Polymer Science 78, No.8, 21st Nov.2000, p.1478-85 ULTRAVIOLET-CURABLE LIQUID NATURAL RUBBER Phinyocheep P; Duangthong S Mahidol University Epoxidised liquid natural rubber was prepared by oxidative degradation of latex using a phenylhydrazine/ oxygen system followed by treatment with performic acid. Photosensitive acrylic acid was bound onto the epoxide ring at a temperature of 80 degrees C. and the reaction was monitored using infrared spectroscopy. Addition of a photocleavage initiator and liquid diacrylate monomer was found to give fast crosslinking under the influence of ultra-violet light, and this reaction was monitored using a double beam photocalorimeter to measure exothermic heat produced from the curing of the acrylate double bond. Investigation of the cure kinetics of the crosslinking reaction indicated that the rate and extent of the reaction were dependant on the diacrylate monomer/photoinitiator concentration. 15 refs THAILAND

Accession no.796697 Item 49 Journal of Rubber Research 3, No.3, 3rd Quarter 2000, p.164-8 INHERENT MOLAR MASS DISTRIBUTION OF CLONES AND PROPERTIES OF CRUMB NATURAL RUBBER Bonfils F; Char C; Garnier Y; Sanago A; Sainte-Beuve J CIRAD; Societe des Caoutchoucs de Grand-Bereby Size exclusion chromatography was used to determine the inherent molar mass distribution of latex samples taken directly from the tree. This was shown, subject to the influence of harvesting and processing, to govern both initial Wallace plasticity and Mooney viscosity of natural rubber prepared from this latex. Examples using rubbers prepared from both latex (5CV60 type) and from cup lump (TSR10 type) are used to illustrate this work. 10 refs EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; IVORY COAST; WESTERN EUROPE

Accession no.796693

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References and Abstracts

Item 50 Journal of Rubber Research 3, No.3, 3rd Quarter 2000, p.142-56 SEASONAL AND CLONAL VARIATIONS IN THE LATEX AND RAW RUBBER OF HEVEA BRASILIENSIS Le Roux Y; Ehabe E; Sainte-Beuve J; Nkengafac J; Nkeng J; Ngolemasango F; Gobina S Cameroon,Institute of Agricultural Research for Development; Buea,University; CIRAD-CP A study of the influences of clonal variations, climactic changes due to seasonal variations, and maturation time of cuplump material on the quality of natural rubber is reported. Quality of natural rubber was assessed by Mooney viscosity, initial Wallace plasticity, plasticity retention index and ash content. The physiological parameters of the latex, collected from the trees before tapping commenced each month, was also examined using a micro-latex diagnosis technique. From this, total solids content, and levels of sucrose, Phosphorus and thiols were assessed. Some significant correlations between total solids content of the latex and Mooney viscosity, and between phosphorus and plasticity retention index, were observed. 18 refs CAMEROON; EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.796691 Item 51 Polymer Testing 20, No.2, 2001, p.151-8 CHEMICAL ANALYSIS OF RUBBER SAMPLES THAT HAD BEEN NATURALLY AGED FOR 40 YEARS Forrest M J Rapra Technology Ltd. Nineteen rubber compounds, which had been aged naturally at locations in Australia and England, were chemically analysed by means of pyrolysis gas chromatography and pyrolysis infrared spectroscopy. The results obtained were compared with those of unaged, remixed samples with similar formulations and attempts made to find a correlation between the data obtained using a relatively simple and rapid technique and those obtained by physical testing using standard test pieces. Depth profiling experiments were also carried out to determine if it was possible to determine differences between the outer surface and middle sections of a relatively thick test piece (Lupke Test Button). 3 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.796645 Item 52 Polymer Degradation and Stability 70, No.3, 2000, p.417-24

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POLYBUTADIENE CROSSLINKED WITH VARIOUS DIOLS - EFFECT ON THERMAL STABILITY Uhl F M; McKinney M A; Wilkie C A Marquette,University Polybutadiene, brominated with N-bromosuccinimide, was crosslinked with the dilithium salts of various diols and the effect of crosslinking on the thermal stability of the brominated polymer investigated. The crosslinked polybutadiene was characterised by gel content and swelling ratio determinations, FTIR spectroscopy and thermal gravimetric analysis. A mechanism of degradation, which occurs in several steps and results in the formation of a significant amount of a non-volatile residue, is proposed. 8 refs. USA

Accession no.794715 Item 53 158th. ACS Rubber Division Meeting - Fall 2000. Conference preprints. Cincinnati, Oh., 17th.-19th. Oct. 2000, paper 101 SOLVING PROBLEMS IN RUBBER FORMULATIONS WITH ANALYTICAL CHEMISTRY Dlunzneski P R Hercules Inc. (ACS,Rubber Div.) Analytical techniques available to the rubber compounder are reviewed. Such techniques can be used in troubleshooting problems and formulation experimentation. The various spectroscopic, chromatographic, and thermo-analytical techniques are described, with details of how they can be applied to solve problems in rubber compounding. USA

Accession no.794199 Item 54 158th. ACS Rubber Division Meeting - Fall 2000. Conference preprints. Cincinnati, Oh., 17th.-19th. Oct. 2000, paper 93 HYDROCARBON RESINS IN CURED ELASTOMER SYSTEMS Schlademan J A; Stockdale M K Goodyear Tire & Rubber Co. (ACS,Rubber Div.) Hydrocarbon resins, used as tackifiers in rubber and adhesive compounds are investigated with reference to their influence on the crosslinking reactions used during processing. Infrared band ratios have been found to be a highly effective means of monitoring the quality and consistency of certain aliphatic C-5 based tackifiers used in these applications. The results of this study indicate that these band ratios may also have value as quality control tools for predicting the effects of these resins on crosslinking reactions in various elastomer compounds.

© Copyright 2001 Rapra Technology Limited

References and Abstracts

Infrared band ratios are also claimed to be potentially valuable as a basis for purchase specifications for ensuring raw material quality and uniformity. 8 refs. USA

Accession no.794191

more detailed characterisation of the mobility of the elastomer network, such as filler-matrix interactions, ageing processes, oils and other organic compounds typically found in rubbers. 23 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.792786 Item 55 158th. ACS Rubber Division Meeting - Fall 2000. Conference preprints. Cincinnati, Oh., 17th.-19th. Oct. 2000, paper 75 CHEMISTRY OF VULCANISATION OF RUBBER Dluzneski P R Hercules Inc. (ACS,Rubber Div.) The advantages are outlined of the use of peroxide vulcanising agents in place of sulphur curing for elastomers. The chemistry of both types of vulcanisation systems is explained. Since the chemical mechanisms of each are very different, rubber compounders, experienced in the use of sulphur are reported to often find difficulties in formulating new products which make use of peroxide curatives. An overview is presented of the types of peroxides available and their properties. A description is included of the chemistry by which peroxides vulcanise rubber, followed by a discussion of the potential chemical interferences which may face rubber compounders converting from sulphur vulcanisation to peroxide curing. USA

Accession no.794176 Item 56 West Conshohocken, Pa., 2000, pp.5. NALOAN ASTM D 3265-. TEST METHOD FOR CARBON BLACK - TINT STRENGTH American Society for Testing & Materials ASTM D 3265Version 2000. Photocopies and loans of this document are not available from Rapra. USA

Accession no.794016 Item 57 Rubber and Plastics News 30, No.6, 13th Oct.2000, p.49-53 USING NMR TECHNIQUES FOR QUALITY CONTROL Kuhn W IIC Innovative Imaging Corp.KG NMR spectroscopy using a dedicated system for crosslink density measurements provides the capabilities to measure the bulk crosslink density of natural rubber, copolymers and blends in a very fast, accurate and fully automatic way. In addition to both types of crosslink density, NMR relaxation parameters can be determined and used for a

© Copyright 2001 Rapra Technology Limited

Item 58 Rubber and Plastics News 30, No.5, 2nd Oct.2000, p.12-4 HIGH-FREQUENCY VISCOELASTICITY OF POLYMER BLENDS Yang H-H; Nikiel L; Gerspacher M; O’Farrell C P Richardson S.,Carbon Co. It has been reported that the wet traction of tyres is associated with the high-frequency viscoelasticity of tyre compounds. An automated acoustic spectrometer was built to measure the high-frequency viscoelastic properties of filled BR/NR and SBR/BR blends. The effects of carbon black loading, polymer blend composition, blend system and mixing technique on the high-frequency viscoelasticity of rubber vulcanisates were studied. The compositional dependence of attentuation coefficient at room temperature depends on the miscibility of polymer blends systems studied. 18 refs. USA

Accession no.792654 Item 59 Kautchuk und Gummi Kunststoffe 53, No.10, Oct.2000, p.592-5 STRUCTURE OF CARBON BLACK AND ITS ASSOCIATIONS IN ELASTOMER COMPOSITES: A STUDY USING NEUTRON SCATTERING Hjelm R P; Wampler W; Gerspacher M Los Alamos National Laboratory Work has been carried out on the use of small-angle neutron scattering and the method of contrast variation to give a new look at reinforcement of elastomers by carbon black in durable rubber products. It was found that in an experimental carbon black, HSA, the aggregates are quasirodlike, containing an average of 4-6 particles. The aggregates have an outer graphite shell and an inner core of lower density carbon. Contrast variation of swollen HSA-polyisoprene gels shows that the HSA is completely embedded in polyisoprene. The agglomerates are formed predominantly by end on associations of the rodlike aggregates. The surface structure of the carbon black appears smooth over length scales above about 1nm. Further studies on production carbon blacks suggest that the shell-like aggregate structure is present in commercial carbon blacks. 8 refs. USA

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Item 60 Kautchuk und Gummi Kunststoffe 53, No.10, Oct.2000, p.566-73 German RELMA - A QUALITY ASSURANCE DEVICE IN THE MIXING ROOM Keuter H; Ackfeld D; Limper A Paderborn,Universitat The RELMA method is a laser induced emission spectral analysis, which is applicable as an instrument for quality assurance in the rubber mixing room. With the RELMA technique, relative element concentrations and their distribution can be determined in a macroscopic scale in usual cycle times of internal mixers. Therefore, quality statements about the compound or even end products can be drawn very fast. Within this paper the optimised RELMA method will be presented and some examples for the application will be shown. In the second part of the application, the RELMA method as a quality assurance instrument for liquids (plasticisers) and disperse solids (carbon black) will be described. 11 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.792612 Item 61 Industria della Gomma 44, No.4, May 2000, p.37-48 Italian VULCANISATION AND SOLID STATE C-13 NMR SPECTROSCOPY Pellicioli L; Negroni F Pirelli Pneumatici SpA Magic angle spinning carbon-13 Fourier transform NMR spectroscopy is examined as a means for studying crosslinking in rubber vulcanisates. Results are presented of studies of vulcanisates based on carbon black and silica filled polybutadiene, SBR and their blends and unfilled SBR. 26 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.790899 Item 62 Rubber Bonding 2000. Conference proceedings. Amsterdam, Netherlands, 15th-16th May 2000, paper 5 CURE KINETICS OF RUBBER-TO-METAL BONDING ADHESIVES Persson S; Olsson T Svedala Skega AB; Lulea,University of Technology (Rapra Technology Ltd.) Since their invention in the 1950s, curemeters have provided the rubber industry and others with valuable information on how the curing reactions of heat-curable rubber compounds are progressing during the

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vulcanisation stage. Since many rubber-to-metal bonds can loosely be described as heat curable rubbers, dissolved in suitable solvents, the same principle of cure metering should therefore apply for rubber-to-metal bonding adhesives as for ordinary rubber compounds. The dynamic mechanical thermal analyser (DMTA) is introduced as an instrument for characterisation of the curing of rubberto-metal bonding agents. The materials studied are Megum 3270 (primer), Megum 100 (adhesive) and NR/ BR (rubber). The method is reliable and necessary, and has excellent potential for optimisation of future bonding agents. 8 refs. EUROPEAN UNION; SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.790031 Item 63 Plastics, Rubber and Composites 29, No.5, 2000, p.229-34 EFFECT OF CAVITY PRESSURE ON CROSSLINK DENSITY OF INJECTION MOULDED SILICONE RUBBER Barbaroux M; Regnier G; Verdu J Dow Corning Healthcare Industries; Ecole Nationale Superieure d’Arts et Metiers The effects of injection moulding conditions (temperatures 120 and 160 deg.C, pressures from 5 to 50 MPa) on the crosslink density of the resulting parts (determined from equilibrium solvent swelling experiments) are studied for an elastomer of the liquid silicone rubber type, in which crosslinking results from platinum catalysed vinyl-silane addition. It is shown, unexpectedly, that a pressure increase leads to an increase in the cure rate, despite the unfavourable effect of pressure on viscosity. 22 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.789932 Item 64 Plastics, Rubber and Composites 29, No.6, 2000, p.253-7 PROCESS OF CURE OF ETHYLENEPROPYLENE DIENE MONOMER RUBBERS. EVALUATION OF STATE OF CURE Azaar K; Lamine B; Granger R; Rosca I D; Vergnaud J M St.Etienne,University; Bucharest,Polytechnic University The process of cure of EPDMs is described by considering the heat conduction through the mould and through the rubber and also the heat generated by the overall cure reaction. The kinetics of the heat evolved from this cure reaction are determined by calorimetry by assuming an Arrhenius’ law for the temperature dependence as well as the cure enthalpy. The cure enthalpy is found to be proportional to the percentage peroxide within the 2-10%

© Copyright 2001 Rapra Technology Limited

References and Abstracts

range, while kinetic parameters such as the preexponential term and the activation energy do not vary with the percentage peroxide. Thus the state of cure, evaluated on a thermodynamic and kinetic basis, can be obtained at any time and position in the sheet. 13 refs. EASTERN EUROPE; EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; RUMANIA; WESTERN EUROPE

Accession no.789896 Item 65 Rubber Chemistry and Technology 73, No.3, July/Aug.2000, p.385-404 SPECTROSCOPIC CHARACTERIZATION OF THE MOLECULAR STRUCTURE OF ELASTOMERIC NETWORKS Koenig J L Case Western Reserve University A review of the literature on the above is presented, covering sulphur vulcanisation mechanism, use of the NMR method for assigning resonances to chemical structure, unaccelerated sulphur vulcanisation of NR, accelerated sulphur vulcanisation of NR and isoprene rubber, sulphur vulcanisation of butadiene rubber, vulcanisation of other elastomer systems, effect of carbon black on vulcanisation of elastomers, effect of silica filler on vulcanisation chemistry, thermooxidation of network structures and NMR imaging of elastomers. 67 refs. USA

Accession no.789317

mechanism in highly prestretched NR and CR are discussed. 34 refs. JAPAN

Accession no.787011 Item 67 Journal of Rubber Research 3, No.2, 2nd Quarter, 2000, p.76-94 PHOTO-CONTROLLED DEGRADATION OF NATURAL RUBBER Solanky S S; Singh R P; Reyx D; Campistron I Pune,National Chemical Laboratory; Le Mans,Universite du Maine In hydrogen peroxide catalysed photo-oxidative degradation of natural rubber, where hydroxy/alkoxy radicals are produced from the hydrogen peroxide or allylic hydroperoxide, the chain cleavage mechanisms are shown to be a classical free radical oxidation process, and not hydroxy radical attack at the methylene-methylene bond. Experimentally, a 2.5 weight percent toluene solution of natural rubber was photolysed at 30 degrees centigrade in a photoreactor under a 400 watt mercury vapour lamp (wavelength approximately 290 nanometers), under both nitrogen and atmospheric air. Fourier transform infra red and carbon thirteen nuclear magnetic resonance spectroscopy were used for characterisation of photoproducts, and viscosity average molecular weigh reduction was monitored by viscosity measurements. 16 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; INDIA; WESTERN EUROPE

Item 66 Polymer Journal (Japan) 32, No.6, 2000, p.505-12 TEM STUDIES ON THIN FILM OF NATURAL RUBBER AND POLYCHLOROPRENE CRYSTALLISED UNDER MOLECULAR ORIENTATION. II. HIGHLY PRESTRETCHED THIN FILMS Tsuji M; Shimizu T; Kohjiya S Kyoto,University Thin films of NR or polychloroprene (CR) are made by casting a 1-2 wt.% solution in n-hexane or benzene onto the water surface, and are prestretched up to a fairly large amount of strain (500-800%) at an ambient temperature in winter-time. Each of the specimens thus prepared is introduced into a transmission electron microscope (TEM) column with a cryo-transfer specimen-holder and examined by TEM observation without any electron staining. Most of the specimens are isothermally crystallised for 1-2 h inside the TEM column by using the holder before TEM observation: at -25 deg.C for NR and at -5 deg.C for CR. On the basis of the morphological observations in bright- and dark-field imaging modes and the selected-area electron diffraction analysis, the identity of the ‘gamma-filaments’ and the crystallisation

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Accession no.786029 Item 68 Journal of Rubber Research 3, No.2, 2nd Quarter, 2000, p.70-5 PARTICLE SIZE DISTRIBUTION OF NATURAL RUBBER LATEX USING ELECTROACOUSTICS Li F; Fellows C M; Gilbert R G; Hunter R J Sydney,University The particle size and distribution in a sample of natural rubber latex diluted to 5 percent solids, as determined electroacoustically in an instrument called an Acoustosizer which uses electrokinetic effects, was compared to similar figures determined by transmission electron microscopy. Results were similar although the shape of the particle size distribution curve was found in each case was a little different, due primarily to instrument effects. Zeta potential determined by both Acoustosizer and other methods were consistent. It was concluded that the Acoustosizer was a valid instrument for determination of particle size distribution in low volume fraction latex samples. 12 refs. AUSTRALIA

Accession no.786028

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Item 69 Journal of Rubber Research 3, No.2, 2nd Quarter, 2000, p.63-9 ASSESSING AGEING RESISTANCE OF CHLORINATED NATURAL RUBBER GLOVES BY THERMOANALYTICAL TECHNIQUE Eng A H; Syahidah Y; Lai P F Rubber Research Institute of Malaysia Differential scanning calorimetry was used to study the ageing resistance of chlorinated natural rubber gloves. The activation energy of oxidation was found to be related to heating rate in accordance with Kissinger’s equation, and correlation with corresponding tensile retention data was linear. Crosslink density of the samples was measured by swelling techniques, but the ratio of crosslink density before and after swelling was not found to correlate with tensile data. The causes of this lack of agreement are considered. 4 refs. MALAYSIA

Accession no.786027 Item 70 Journal of Rubber Research 2, No.4, 4th Quarter, 1999, p.231-8 STRUCTURAL CHARACTERISATION OF WILD RUBBER: GEL CONTENT Marinho J R D; Tanaka Y Universidade Estadual; Tokyo,University of Agriculture & Technology Latex, chemically treated by deproteinisation and transesterification, and extracted from other species of the Hevea family, Hevea Euphorbiaceae and Hevea Moraceae, was compared with that from Hevea Brasiliensis to examine the gel content. Composition of latex and presence of soft (soluble) gel depended on the botanical family. Hard gel, caused by chemical crosslinking between the polymer chains, appears dependent on extended storage. Molecular weight of samples was determined by size exclusion chromatography, and structural information on the polymer chain by nuclear magnetic resonance spectroscopy. 17 refs. BRAZIL; JAPAN

Accession no.786025 Item 71 Journal of Rubber Research 2, No.4, 4th Quarter, 1999, p.223-30 PHOTODEGRADATION OF RAW NATURAL RUBBER UNDER CONTROLLED CONDITION Maidunny Z A Rubber Research Institute of Malaysia A one kilowatt solar simulator was used to study the photodegradation of various grades of both filled and unfilled natural rubber and synthetic polyisoprene. Molecular weight variation with exposure was determined using high-pressure liquid chromatography. Introduction

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of photosensitisers improves the efficiency of degradation of the rubber, as does the presence of chromophores which are present in greater quantity in the less-pure samples of rubber. 15 refs. MALAYSIA

Accession no.786024 Item 72 Polymer International 49, No.7, July 2000, p.691-8 RADIATION DEGRADATION OF EPOXIDISED NATURAL RUBBER STUDIED BY SOLID-STATE NUCLEAR MAGNETIC RESONANCE AND INFRARED SPECTROSCOPY Perera S Griffith University The mechanism of radiation-induced structural changes in epoxidised NR is investigated using NMR and Fourier transform infrared (FTIR) spectroscopy. Samples are irradiated both under vacuum and in air. Because the rubbers crosslink during irradiation, solid-state NMR has to be used. The cross polarised/magic angle spinning NMR spectra are used to calculate the radiation yields. Ring opening of the epoxy groups is found to occur during irradiation. Most of the crosslinking is due to epoxy group ring opening, and very little or no C-C crosslinking is observed. 23 refs. AUSTRALIA

Accession no.784064 Item 73 Polymer International 49, No.7, July 2000, p.633-5 RAPID REPORT CHARACTERISATION OF SILOXANE RESIDUES FROM POLYDIMETHYLSILOXANE ELASTOMERS BY MALDI-TOF-MS Hunt S M; George G A Queensland,University of Technology The hydrophobic recovery properties of polydimethylsiloxane (PDMS) elastomers after environmental degradation arises from the migration of low molecular weight siloxanes from the bulk to the surface. MALDI-TOF-MS analysis of the isotopic distribution of oligomers from the surface of vulcanised PDMS enables unambiguous assignment of these as predominantly cyclic siloxanes ranging from 13 to 47 repeat units with smaller proportions of methyl and hydroxyl terminated linear chains ranging from 12 to 24 repeat units. 11 refs. AUSTRALIA

Accession no.784055 Item 74 China Synthetic Rubber Industry 23, No.4, July 2000, p.219-21

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References and Abstracts

Chinese CURING KINETICS OF PU ELASTOMERS BY FTIR Zaifeng L; Zhenqin X; Caifeng D; Zhaolian G; Dehe L; Guanghua Y Qingdao,Institute of Chemical Technology; Beijing,University of Petroleum The kinetics of curing reaction of PU elastomers is analysed by in situ quantitative FTIR. The reactions, uncatalysed and catalysed by dibutyltin dilaurate (DBTDL), follow second-order kinetics at low conversion. At high conversion, however, the secondorder rate constants decrease with the increase of reaction extent, due to the influence of diffusion control. The reaction kinetics parameters are given and the possible reaction mechanism is further offered. DBTDL is an effective positive catalyst for the reaction of -NCO with OH. 8 refs. CHINA

Accession no.783773 Item 75 ACS Polymeric Materials: Science & Engineering.Spring Meeting 2000.Volume 82.Conference proceedings. San Francisco, Ca., 26th-30th March 2000, p.148 FUNCTIONAL NMR IMAGING OF MATERIALS Blumich B; Demco D E; Stapf S; Goerke U; Chwatinski C; Gasper L; Giesen R; Haken R; Han S Aachen,Institut fur Technische Chemie & Makromolekulare Chemie (ACS,Div.of Polymeric Materials Science & Engng.) The use of nuclear magnetic resonance spectroscopy for the study of stress distributions in strained elastomers, and for the flow of complex fluids is briefly described. It is shown that a homogeneous magnetic field is not required for some studies, which significantly reduces the cost of the technique and facilitates its use outside the laboratory. 8 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.783290 Item 76 Rubber Chemistry and Technology 73, No.2, May-June 2000, p.293-309 SURFACE ACTIVITY AND CHEMISTRY OF THERMAL CARBON BLACK Darmstadt H; Cao N-Z; Pantea D M; Roy C; Suemmchen L; Roland U; Donnet J-B; Wang T K; Peng C H; Donnelly P J Institut Pyrovac Inc.; Dresden,Technische Universitat; Ecole Nationale Superieure de Chimie de Mulhouse; Cancarb Ltd.

Using inverse gas chromatography at infinite dilution, the surface energy of thermal and furnace carbon blacks was determined. The carbon black surface and bulk chemistry were examined using various techniques. A correlation between the surface energy and the polyaromatic character of the carbon black was established. There were no principal differences in surface morphology between thermal and other blacks produced from high purity feedstocks. 24 refs. CANADA; EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; GERMANY; WESTERN EUROPE

Accession no.783006 Item 77 Polymer 41, No.20, 2000, p.7483-8 CHARACTERISATION OF FATTY ACIDS LINKED TO NATURAL RUBBER - ROLE OF LINKED FATTY ACIDS ON CRYSTALLISATION OF THE RUBBER Kawahara S; Kakubo T; Sakdapipanich J T; Isono Y; Tanaka Y Nagaoka,Technological University; Tokyo,University of Agriculture & Technology; Mahidol University A study was made of fatty acids attached to NR molecules using proton NMR spectroscopy and gas chromatography. The effect of attached fatty acids on the crystallisation behaviour of NR was also investigated using differential scanning calorimetry. The types of fatty acid esters having groups attached to the NR molecules were identified as stearic acid, oleic acid, linoleic acid and linoleinic acid. The linked saturated fatty acid ester groups were found to act as nucleating agents during the crystallisation of NR, as confirmed by experiments on model polyisoprenes esterified with fatty acids at the 3,4 isomeric unit. 26 refs. JAPAN; THAILAND

Accession no.781457 Item 78 Rubber Chemistry and Technology 73, No.1, March/April 2000, p.47-55 FTIR INVESTIGATION OF THE MOLECULAR STRUCTURE AT THE CRACK INTERFACE IN UNFILLED AND SILICA FILLED POLYISOPRENE Glime J; Koenig J L Case Western Reserve University Unfilled and silica-filled polyisoprenes were stretched until cracking was initiated. The crack interface was then studied using FTIR to investigate the changes in the molecular structure induced by crack formation. DSC was used to determine the crystallinity of the rubber after it was stretched. 14 refs. USA

Accession no.781124

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References and Abstracts

Item 79 Journal of Polymer Science: Polymer Physics Edition 38, No.11, 1st June 2000, p.1417-23 SOLID-STATE NMR STUDIES OF CIS-1,4POLYISOPRENE CROSSLINKED WITH DICUMYL PEROXIDE IN THE PRESENCE OF TRIALLYL CYANURATE Sung Joon Oh; Koenig J L Case Western Reserve University Solid-state techniques such as direct-polarisation(DP), cross-polarisation(CP) and proton T2 experiments were used to study the network of dicumyl peroxide(DCP)/ triallyl cyanurate(TAC) crosslinked cis-1,4-polyisoprene. Line broadening and cis/trans isomerisation of mobile carbons were observed in the DP experiments. Rigid carbons of network structures was observed with the CP technique. Motional heterogeneity was examined by proton T2 relaxation experiments. Decreases in long T2 values from the mobile non-network structures and short T2 values from the rigid network structures were observed with an increase in peroxide or coagent concentration. The percentage of short T2 in T2 relaxation, which was related to network density, was observed to increase with peroxide and coagent addition. 28 refs. USA

Accession no.781016 Item 80 Polymer Testing 19, No.6, Sept.2000, p.667-72 ANALYSIS OF NATURAL CIS-AND TRANSPOLYISOPRENE MIXTURES BY NEARINFRARED SPECTROPHOTOMETRY Marinho J R D; Monteiro E E C UNESP; Rio de Janeiro,Universidade Federal Natural trans- and cis-polyisoprenes and mixtures of these polymers are analysed by near-infrared spectrophotometry. The relative absorptivity data versus the amount of isomers in synthetic mixtures show a non-linear behaviour. The results are compared with data from polyisoprenes extracted from other vegetal species. 9 refs. BRAZIL

Accession no.780854 Item 81 Polymer Testing 19, No.5, Aug.2000, p.591-602 AGEING OF ETHYLENE-PROPYLENE DIENE RUBBER (EPDM) VULCANISED BY GAMMARADIATION Abdel-Aziz M M; Basfar A A Saudi Arabia,Institute of Atomic Energy Research The results are reported of a study of the effects of several polyfunctional compounds, as crosslinking coagents, on the irradiation vulcanisation of EPDM and of several

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antioxidants and their mixtures on the thermal degradation and accelerated weathering of the EPDM vulcanisates. The coagents employed were polyethylene glycol diacrylates and a modified triacrylic ester and the antioxidants were Irganox 1076, Irgafos 168, Tinuvin 622LD, IPPD and trimethyl quinoline. Correlations between antioxidant type, concentration and efficiency were investigated by means of TGA and DSC and irradiated samples were subjected to tensile testing after heat ageing at 100C for 28 days and accelerated ageing up to 200 hours. 12 refs. SAUDI ARABIA

Accession no.779499 Item 82 Nippon Gomu Kyokaishi 73, No.5, 2000, p.274-6 Japanese IN SITU TEM OBSERVATION OF NATURAL RUBBER THIN FILMS CRYSTALLISED UNDER MOLECULAR ORIENTATION Shimizu T; Tosaka M; Tsuji M; Kohjiya S Transmission electron microscopy is used to provide data on the structure of the natural rubber thin films after stretching. 10 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. Accession no.779419 Item 83 Rubber Chemistry and Technology 72, No.5, Nov./Dec.1999, p.862-75 ATOMIC FORCE MICROSCOPY OF ELASTOMERS: MORPHOLOGY, DISTRIBUTION OF FILLER PARTICLES, AND ADHESION USING CHEMICALLY MODIFIED TIPS Trifonova-Van Haeringen D; Schoenherr H; Vancso G J; Van der Does L; Noordermeer J W M; Janssen P J P Twente,University; Oce-Nederland BV Atomic force microscopy(AFM) was used to investigate the microdispersion of silica and carbon black-based filler particles in unvulcanised and vulcanised EPDM rubbers. Tapping mode phase imaging was found to be particularly useful for imaging of the filler aggregates and for visualisation of single primary filler particles. It was demonstrated that the use of silane coupling agents significantly improved the microdispersion of silica filler in the rubber matrix, as compared with silica without coupling agent and with carbon black. These results correlated well with the observed mechanical properties of the materials. In addition, adhesion imaging and the analysis of measured pull-off forces allowed differentiation between the filler particles and the rubber matrix, as well as between different types of filler particles. The application of chemically modified AFM tips in pull-off force

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References and Abstracts

measurements allowed monitoring of the increase of the hydrophilicity as a result of plasma treatment of the surface of crosslinked polydimethylsiloxane and as a result of chlorination of butyl rubber. 36 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.778379 Item 84 Rubber Chemistry and Technology 72, No.5, Nov./Dec.1999, p.844-53 NOVEL METHOD FOR 13C-NMR SPECTROSCOPY OF POLYMER IN EMULSION: QUANTITATIVE ANALYSIS OF MICROSTRUCTURE OF CROSSLINKED POLYBUTADIENE IN LATEX Kawahara S; Bushimata S; Sugiyama T; Hashimoto C; Tanaka Y Nagaoka,Technological University; Tokyo,University of Agriculture & Technology An analytical method based on high-resolution carbon13 NMR spectroscopy was used to study polymer latex. Suitable concentrations of surfactant and dried rubber content of a polybutadiene latex, which gave the best spectrum, were found to be 1 w/v % and 10%, respectively. The half-widths of resonance peaks for the latex sample were almost identical to the half-widths obtained in solution, which were about one-third the width of those obtained using a solid sample of either a crosslinked or soluble polybutadiene. The signal to noise ratio for the latex sample was slightly smaller than that for the solution sample. The values of spin-lattice relaxation time, T1, for the latex sample were similar to those for the solid sample. These demonstrated that the latex state carbon-13 NMR spectroscopy was a powerful technique for structural characterisation of crosslinked gels in the dispersoid because it gave a high resolution spectrum comparable with solution state spectroscopy, showing short T1 values corresponding to those for solid state carbon-13 NMR spectroscopy. High resolution latex state carbon-13 NMR spectroscopy was used to determine the concentrations of the various isomers of the polybutadiene in the dispersoid. 13 refs. JAPAN

Accession no.778377 Item 85 Rubber Chemistry and Technology 72, No.5, Nov./Dec.1999, p.829-43 FOURIER TRANSFORM RAMAN SPECTROSCOPY FOR CHARACTERIZATION OF NATURAL RUBBER REVERSION AND OF ANTIREVERSION AGENTS Datta R N; Hofstraat J W; Geurts F A J; Talma A G Flexsys BV; Akzo Nobel Central Research

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Fourier transform Raman spectroscopy was used to study the mechanism of reversion and the influence of the antireversion agent, 1,3-bis(citraconimidomethyl)benzene(BCI-MX), in squalene as well as in low molec.wt. synthetic polyisoprene. The formation of non-sulphidic main chain modifications, such as conjugated diene and triene units, along the squalene and isoprene backbone was followed by using this technique. The mode of action and the efficacy of BCI-MX were studied. The decrease in concentration of conjugated diene and trienes by the addition of BCI-MX confirmed the reaction of BCIMX with polyenes to be a Diels-Alder reaction. In addition to the detection of reversion reactions, other processes which occurred during rubber vulcanisation were also monitored using Raman spectroscopy. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.778376 Item 86 Applied Spectroscopy 54, No.4, April 2000, p.528-35 ON-LINE MONITORING OF A LATEX EMULSION POLYMERISATION BY FIBREOPTIC FT-RAMAN SPECTROSCOPY. I. CALIBRATION Bauer C; Amram B; Agnely M; Charmot D; Sawatzki J; Dupuy N; Huvenne J-P CNRS; Lille,Universite des Sciences et Technologies; Rhodia; Bruker Optik GmbH; Lille,Ecole Universitaire d’Ingenieurs The preparation of SBR latex by emulsion copolymerisation was monitored on-line using fibre-optic Fourier transform spectroscopy. Two partial least-squares calibration models with mean-centered spectra over the 3500 to 2700 U 1800-500 cm/1 spectral range were developed and four factors were employed to model the evolution of the dry extract. A two-factors model was used to calibrate the amount of free styrene. 17 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.777539 Item 87 International Polymer Science and Technology 27, No.3, 2000, p.T/42-T/44. (Translation of Kauchuk I Rezina, No.5, 1999, p.23) IMPROVEMENT IN DYNAMIC CHARACTERISTICS OF VULCANISATES Murav’eva L V; Metik V V; Krainokov A V; Vedeneev A I Lomonosov M.V.,State University; Russia,Military Automobile Institute Trials were carried out using different oxidation stabilisers on compounds of butadiene-acrylonitrile rubber. Parts manufactured from these vulcanisates are required to undergo considerable dynamic and consequently, thermal loads and have a long service life, and so to improve the

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thermal stability of this rubber, a new polyfunctional inhibitor M-9 has been developed to inhibit the processes of thermooxidative degradation. The inhibiting effectiveness of the new antiager was studied by means of thermogravimetry and viscometry under isothermal conditions and IR spectroscopy at oxidation temperatures of the rubber ranging from 120 -180 degrees C. The stabilising effectiveness of the new compound was compared with the traditionally used antioxidant Diaphan FP and the new polyfunctional inhibitor B-25. 5 refs. RUSSIA

Accession no.775893 Item 88 New Scientist 166, No.2243, 17th June 2000, p.6 RAPIST BRANDED A new condom “fingerprinting” test is being developed by the University of Technology in Sydney which could help provide evidence to convict a rapist. It has been shown that most brands of Australian condoms can be distinguished using NMR spectroscopy to analyse the molecular structure of a fragment of condom. In total, 33 of the 38 condoms tested could be identified. Eventually, it is hoped to be able to identify all condoms solely by their NMR spectra, using only a vaginal swab. SYDNEY,UNIVERSITY OF TECHNOLOGY AUSTRALIA

Accession no.775788

expressed using a stochastic model of transitional diffusion of structural defects between fixed and fluctuating of the polymer chains. The radiation was found to yield changes in the constrained defect diffusion processes modelling the chain dynamic. 21 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.773133 Item 91 Journal of Macromolecular Science B B38, Nos. 5 & 6, 1999, p.1009-22. NMR RELAXATION AND NMR IMAGING OF ELASTOMERS IN THE COURSE OF THERMAL AGEING Knorgen M; Heuert U; Schneider H; Heinrich G Martin-Luther-Universitat Halle; Continental AG In the course of thermal ageing of elastomers a complex regime exists dependant upon the fillers, temperature, time and the chemical environment. This can be observed by nuclear magnetic resonance methods. One of these methods, using spin-echo can track the decay of the echo magnetisation using a single-chain model with a distribution of dipolar interactions. The experiments used were natural rubber, emulsion and solution polymerised styrene butadiene copolymers. The model is based on the influence of the motions involved which can diminish the residual dipolar interactions. 14 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.773132 Item 89 China Rubber Industry 47, No.5, 2000, p.288-91 Chinese DETERMINATION OF SILICA CONTENT IN RUBBER Wu S-h; Li Z-c 2 refs. CHINA

Accession no.774176 Item 90 Journal of Macromolecular Science B B38, Nos. 5 & 6, 1999, p.1023-35. NMR AND DSC INVESTIGATIONS OF DYNAMIC ASPECTS OF AGEING IN POLYMERS Denner P; Deutschbein L; Walter B Ilmenau,Technische Universitat The dynamical aspects of ageing of cis 1-4 polybutadiene have been examined by proton spin relaxation above the glass transition temperature and differential scanning calorimetry. The polymer chains were crosslinked by ionizing radiation exposure. The relaxation data is

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Item 92 Journal of Applied Polymer Science 76, No.9, 31st May 2000, p.1377-85 BENZOTHIAZOLE-ACCELERATED SULPHUR VULCANISATION. 1. 2MERCAPTOBENZOTHIAZOLE AS ACCELERATOR FOR 2,3-DIMETHYL-2BUTENE Morgan B; McGill W J Port Elizabeth,University A study was made of 2-mercaptobenzothiazole-accelerated sulphur vulcanisation using 2,3-dimethyl-2-butene as a model compound for polyisoprene. High-performance chromatography was employed to analyse heated mixtures containing the curatives only and the curatives and the model compound for residual curatives, intermediates and reaction products. The data obtained indicated that the accelerator formed polysulphidic species in the presence of sulphur, which react with the model compound to form polysulphidic hydrogen-terminated pendent groups, and that crosslinking occurred slowly as a result of the interaction of polythiol pendent groups. 25 refs. SOUTH AFRICA

Accession no.772402

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References and Abstracts

Item 93 Journal of Applied Polymer Science 76, No.7, 16th May 2000, p.1019-27 EFFECT OF COUPLING AGENT AND CHEMICAL TREATMENT ON RICE HUSK ASHFILLED NATURAL RUBBER COMPOSITE Da Costa H M; Visconte L L Y; Nunes R C R; Furtado C R G Rio de Janeiro,Universidade Federal; Rio de Janeiro,Universidade do Estado A study was made of the use of rice husk ash as a filler in a natural rubber compound. Various levels of both milled husk ash (MHA), prepared by milling husk ash and sieving through a 250 mesh sieve, and treated husk ash (THA), prepared by chemical treatment of the milled husk ash, were studied and compared to both a carbon black filled and a silica filled compound. Silane treatment of the husk ash was also examined, with less effect than was expected. Both physical testing of vulcanisates, and electron microscopy studies on the fracture surface of the tensile specimens were used in this study, with an initial examination of the filler by infra-red spectroscopy to determine the presence of precipitated silica groups in both MHA and THA. Physical results were generally lower than is obtained with carbon black or silica, although quite respectable results were obtained at low to medium loading. 13 refs. BRAZIL

Accession no.771966 Item 94 Gummi Fasern Kunststoffe 53, No.2, 2000, p.97-9 German PROCESS FOR DETERMINING THE CONTENT OF ORGANIC SILICON COMPOUNDS ON THE SURFACE OF ELASTOMERIC SEALANTS Gross T; Unger W The use of electron spectroscopy for chemical analysis (ESCA) to provide information on silicon compounds present on the surface of elastomeric sealants is described. 4 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. Accession no.771822 Item 95 Polymer Bulletin 44, No.2, March 2000, p.187-94 USE OF MICROWAVE DIELECTRIC LOSS SPECTROSCOPY FOR CHARACTERISATION OF NATURAL RUBBER/CARBON BLACK COMPOSITES Lucchese L; Liauw C M; Allen N S; Edge M; Thompson F; Whitehouse R S

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Manchester,Metropolitan University; CABOT Technical Centre Microwave dielectric loss spectroscopy was used to study the thermal degradation of natural rubber containing furnace grade carbon black. During crosslinking the dielectric loss progressively increased, but during ageing in air at 150 C, the dielectric loss decreased. Parallel studies on the unfilled matrix showed no dielectric loss variation. It was concluded that the observed changes were related to the development of the interface during curing and its subsequent destruction during ageing. The effects of stabilisers were also investigated. 6 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; USA; WESTERN EUROPE

Accession no.771775 Item 96 157th ACS Rubber Division Meeting - Spring 2000. Preprints. Dallas, Tex., 4th-6th April 2000, paper 44 MICROSCOPY AND ULTRAMICROTOMY AS USEFUL TOOLS FOR THE RUBBER INDUSTRY Roberts D; Couch E F; Wampler W Richardson S.,Carbon Co.; Texas,Christian University (ACS,Rubber Div.) The electron microscope has proved to be a very useful tool in the investigation of carbon black. As it makes use of the very short wavelength of the electron it is possible to achieve extremely high resolution, a feature especially useful when studying the nanometre-sized carbon black particles. Through its use, early workers were able to demonstrate that the size and structure of the carbon black mixed with rubber had a direct effect on its properties. Recently, however, there has been an increased interest in the actual interaction of the carbon black with its rubber matrix. This has prompted efforts to examine the topographical relationship between the rubber matrix and the carbon filler. One promising approach to achieve this is to examine ultra-thin sections of carbon black filled rubber. But this approach has not been easy. Rubber at room temperature simply cannot be sectioned into sections thin enough for electrons to penetrate them. This obstacle can be overcome, however, if the rubber is cooled to very low temperatures. Then with a suitable microtome and knife it is possible to make ultra-thin sections that can be studied with by transmission electron microscopy. This technique is described, pointing out the advantages and disadvantages of this technique together with possible solutions. 8 refs. USA

Accession no.771683 Item 97 157th ACS Rubber Division Meeting - Spring 2000. Preprints. Dallas, Tex., 4th-6th April 2000, paper 43

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SOLID STATE 13C-NMR SPECTROSCOPY ON ACCELERATED SULPHUR VULCANISED CARBON-13 LABELLED EPDM RUBBER Winters R; Lugteriburg J; de Groot H J M; van Duin M Leiden,Institute of Chemistry; DSM Research NV (ACS,Rubber Div.) Accelerated sulphur vulcanised 13C labelled EPDM is analysed using 13C solid state NMR to determine the chemical microstructure of the network. Two formulations are analysed - one with carbon black and oil and one without carbon black and oil. Analysis with high resolution solid-state 13C NMR reveals that sulphur crosslinking takes place at the allylic positions of ENB in agreement with prior low molecular weight model olefin studies. The formulations yield the same network structure. From the integrated intensities of the 13C signals, the conversion of ENB into a crosslink in time can be quantitatively determined with a maximum of 23% of total ENB content. Upon prolonged heating oxidation and reversion of the crosslinks take place. Reversion yields two main products, viz retro formation of ENB and a 4,5,6,7-tetrahydro-4,7-methanobenzo(b)thiophene compound. 20 refs. USA

Accession no.771682

approximate linear increase in these degradation functionalities with increasing oxidation level. 59 refs. USA

Accession no.770514 Item 99 Rubberchem ’99. Conference proceedings. Antwerp, Belgium, 22nd-23rd Nov.1999, paper 17 ELASTOMERIC COMPOUNDS FOR CONTACT WITH FOOD Sidwell J Rapra Technology Ltd. (Rapra Technology Ltd.) Although European Directives have been issued on legislative requirements for food contact plastics, European harmonisation of regulations for rubber or thermoplastic elastomers used in contact with food is yet to occur. The current national requirements within Europe for food contact elastomers are reviewed, including a draft resolution being prepared by the Council of Europe. Findings of a study undertaken at Rapra for MAFF (UK) on the migration of species from a range of food-contact elastomeric compounds are also discussed. 3 refs. EUROPE-GENERAL; EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.769259 Item 98 Macromolecules 33, No.4, 22nd Feb.2000, p.1181-90 INVESTIGATION OF OXIDATIVE DEGRADATION IN POLYMERS USING 17O NMR SPECTROSCOPY Alam T M; Celina M; Assink R A; Clough R L; Gillen K T; Wheeler D R Sandia National Laboratories The thermal oxidation of pentacontane (C50H102) and polyisoprene was studied using 17O NMR spectroscopy. The use of 17O-labelled oxygen for the oxidation process facilitated the identification of non-volatile degradation products, even at low concentrations. With pentacontane, at low levels of oxygen incorporation, the major oxidation products were peroxides, whilst at later stages these species were replaced by increasing concentrations of ketones, alcohols, carboxylic acids, and esters. The analysis of the product distribution helped to identify different free-radical decomposition paths of hydroperoxides, including recombination, proton abstraction, and chain scission. Polyisoprene revealed fewer degradation functionalities, but an increased complexity in the type of degradation species was observed, attributed to structural features such as unsaturation and methyl branching. Alcohols and ethers formed by hydrogen abstraction and free radical termination reactions were the main oxidation products. Compared with pentacontane, the formation of esters and carboxylic acids was relatively minor. There was an

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Item 100 Rubber Chemistry and Technology 72, No.4, Sept./Oct.1999, p.712-20 LONG-CHAIN BRANCHING AND MECHANISM CONTROLLING MOLECULAR WEIGHT IN HEVEA RUBBER Sakdapipanich J T; Kowitteerawut T; Suchiva K; Tanaka Y Bangkok,Mahidol University; Tokyo,University of Agriculture & Technology The linear character of transesterified deproteinised NR was confirmed by the analysis of terminal groups. Data from NMR, GPC and viscometric analyses are discussed. 24 refs. JAPAN; THAILAND

Accession no.767924 Item 101 Macromolecules 33, No.2, 25th Jan.2000, p.326-30 PRIMARY PYROLYSIS PRODUCTS OF HYDROXY-TERMINATED POLYBUTADIENE Ganesh K; Sundarrajan S; Kishore K; Ninan K N; George B; Surianarayanan M Indian Institute of Science; Vikram Sarabhai Space Centre; India,Central Leather Research Institute The degradation of hydroxy-terminated polybutadiene (HTPB), which is used as a binder in solid propellants,

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References and Abstracts

was studied using direct pyrolysis mass spectrometry. The degradation involved a radical process which formed cyclic compounds, as well as beta-CH transfer reactions forming linear oligomers. From considerations of heat of formation data, it was concluded that the formation of 1,3-butadiene monomer was not favoured during the primary chain scission process, but its formation occurred by the dissociation of high molecular weight cyclic and linear oligomers. The presence of strong oxidisers, such as ammonium perchlorate, significantly affected the degradation of HTPB. 18 refs. INDIA

Accession no.767554 Item 102 Journal of Polymer Research 6, No.2, April 1999, p.67-78 STUDY ON THERMAL TRANSITIONS OF TOLUENE DIISOCYANATE-BASED POLYURETHANE ELASTOMERS WITH POLY(TETRAMETHYLENE OXIDE) AS THE SOFT SEGMENT BY TSC/RMA, DSC AND DMA THERMAL ANALYZERS Jung-Mu Hsu; Der-Lern Yang; Huang S K Taiwan,National University of Science & Technology The thermal transitions of the above elastomers were characterised by thermally stimulated depolarisation current(TSDC) measurements and by using the thermal windowing technique on selected specimens in the relaxation mapping analysis(RMA) measurements. Results indicated that the broadened thermal transition in the Tg region as observed in the DSC thermogram was related to the combined Tg transition and the T(global) transition in the TSDC spectrum. The increase in the Tg with a high NCO content could be explained by the structural modification found on the urethanic chain with the additional linkage of the hard segment that affected the cooperative motion of the molecular chain. Data measured from DSC, TDSC/RMA and DMA with simulated DEA and wide-angle X-ray diffraction data were used to characterise the PUs. The RMA measurement led to a compensation search on Tg transition and provided relevant thermokinetic data that correlated the NCO content with changes in enthalpy and entropy on the relaxation behaviours in the Tg transition of PU elastomers. 41 refs. TAIWAN

Accession no.764962 Item 103 International Polymer Science and Technology 26, No.8, 1999, p.T/34-T/37. (Translation of Kauchuk i Rezina, No.3, 1999, p.2) STUDY OF FILLED BLENDS OF INCOMPATIBLE RUBBERS BY MEANS OF XRAY DIFFRACTION ANALYSIS

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Kiselev V Y Lomonosov Institute of Fine Chemical Technology The aim of this work is to study the degree of crystallinity of natural rubber in blends with incompatible elastomers that contain various fillers. The investigation was carried out on natural rubber and on butadiene-acrylonitrile rubbers and polyurethane rubbers with polar fine colloidal silicas as fillers. Electron microscope studies carried out showed that the closer the polarity of the rubbers, the smaller is the size of the dispersed phase, and the greater the difference in polarity of the mixed rubbers, the greater is the amount of non-polar component in the surface layer of the blend. Crystallisation of the natural rubber within the blend of incompatible elastomers depends both on the nature of the polymer components and on the volume ratio of their phases. The introduction of fillers leads to a reduction in the degree of crystallinity of the NR, the magnitude of this reduction being influenced by the nature of the filler. Thus, the use of X-ray diffraction analysis makes it possible by a non-destructive method, to assess the interaction between incompatible polymers, and to establish the role of highly dispersed filler particles in the formation of a strong bond in the rubber-filler adhesion system. 15 refs. RUSSIA

Accession no.764807 Item 104 Rubber Chemistry and Technology 72, No.2, May-June 1999, p.384-97 CARBON BLACK SURFACE CHARACTERIZATION BY TOF-SIMS AND XPS Bertrand P; Weng L T Louvain,Universite Catholique The two analytical techniques, Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and X-ray Photoelectron Spectroscopy (XPS) have been found to be very complementary in the study of surface adsorption, microstructure and activity of carbon black. The sensitivity of the former (TOF-SIMS) is much higher than the latter (XPS) but quantification is much better with XPS. TOF-SIMS in particular has been shown to give information, not only on the functional groups attached, but also on the surface aromaticity and specific high mass structures which appear to be important in the construction of the carbon black particle. (Originally presented to ACS meeting, Indianapolis, May 5-8, 1998, revised July 98) 25 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.763832 Item 105 Rubber Chemistry and Technology 72, No.2, May-June 1999, p.334-42

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STUDIES OF PEROXIDE CURING OF CIS-1,4POLYISOPRENE/DIALLYL PHTHALATE BLENDS BY SPECTROSCOPIC TECHNIQUES Sung Joon Oh; Koenig J L Case Western Reserve University,Dept.of Macromolecular Science Differential scanning calorimetry (DSC), solid state nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR) and equilibrium swelling techniques were used to study the peroxide curing of cis1,4-polyisoprene with addition levels of coagent diallyl phthalate from 0 to 20 percent by weight. It is postulated that, although reaction kinetics are controlled by rate of peroxide decomposition, the coagent catalyses the curing reactions and undergoes both copolymerisation and homopolymerisation during the reaction. Chemically bound coagent domains, which are phase separated are suggested to cause a decrease in segmental mobility with increase in crosslink density. 20 refs

Item 107 Angewandte Makromolekulare Chemie Vol.271, Nov.1999, p.61-7 CHROMATOGRAPHIC INVESTIGATIONS OF MACROMOLECULES IN THE CRITICAL RANGE OF LIQUID CHROMATOGRAPHY. XIII. SEPARATION OF BLENDS OF SBR AND BUTYL RUBBER Essex K E; Braun D; Pasch H Darmstadt,Deutsches Kunststoff-Institut The separation of blends of SBR and butyl rubber was achieved by liquid chromatography at the critical point of adsorption. Using a non-polar stationary phase and methyl ethyl ketone-cyclohexane as the eluent, the critical point of adsorption of BR was established. The exact chemical structure of the blend components was analysed by coupling the chromatographic separation to FTIR detection. 19 refs.

USA

EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

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Accession no.762117

Item 106 Journal of Applied Polymer Science 75, No.5, 31st Jan.2000, p.660-9 INFLUENCE OF MIXING PROCEDURES AND CURING TIME ON MOLECULAR AND TOPOLOGICAL STRUCTURES OF NR/BR VULCANIZATE Jurkowska B; Olkhov Y A; Jurkowski B; Olkhova O M Stomil Rubber Research Institute; Russian Academy of Sciences; Poznan,University of Technology

Item 108 Angewandte Makromolekulare Chemie Vol. 270, Sept. 1999, p. 81-6 CARBON BLACK NITRATION AND NITROSATION AND IT’S APPLICATION TO IMPROVE THE MECHANICAL HYSTERESIS OF A RUBBER TREAD COMPOUND Cataldo F Soc.Lupi arl

Thermomechanical analysis was used to study the influence of mixing procedures and curing time on the structure of blends of butadiene rubber (BR) and natural rubber (NR), containing carbon black. After 20 min vulcanisation, a block structure developed, consisting of two blocks with different transition temperatures. A lowtemperature block was characterised by covalent branching junctions, not influenced by the mixing procedures, whereas the high-temperature block had covalent and topological junctions in concentrations that were dependent upon the mixing method. For curing times in excess of 20 min, changes in molecular weight were dependent upon the mixing procedure. Following further homogenisation and vulcanisation, the rubbers had a characteristic diblock structure. When the carbon black was blended with BR, followed by the addition of NR, the blends were less sensitive to additional homogenisation during further processing. A mechanism is proposed for the creation and transformation of rubbercarbon black junctions during compounding and vulcanisation, where two raw rubbers of different absorptions are used. 29 refs. EASTERN EUROPE; POLAND; RUSSIA

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The chemical structure of a conventional N234 carbon black was carried out using dinitrogen trioxide, nitrogen oxide and dinitrogen tetraoxide in a low temperature treatment. The chemical structure of the resulting black was studied by FT-IR spectroscopy. Extensive nitrosation, nitration and oxidation of the black’s surface was found. Raman spectroscopy showed that the bulk structure was substantially unchanged. In testing in a conventional tread compound, tan delta at 70 degrees centigrade was found to be reduced by some 14%, without significant losses in traction performance. 25 refs EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.760475 Item 109 156th ACS Rubber Division Meeting - Fall 1999. Conference preprints. Orlando, Fl., 21st-23rd Sept.1999, paper 121 SOLID STATE NMR TO CHARACTERISE SILICA Mansencal R L; Evans L R Huber J.M.,Corp.,Engineered Minerals Div. (ACS,Rubber Div.)

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References and Abstracts

NMR spectroscopy is shown to be a valuable tool to investigate the surface chemistry of amorphous precipitated silica. The surfaces of two different highly dispersible silicas are shown to differ in the number and distribution of their hydroxyl groups. Z8715 presents a higher hydroxyl content and more geminal hydroxyl concentration than Z8745. NMR is been shown to be a reliable technique to investigate the reaction of two model silane molecules with the hydroxyls on a silica surface. The reactivity of the two silanes differ with TCMS showing a higher affinity for reaction with isolated silanols than does MTCS. Additionally, techniques of x-ray scattering, SMS and USAXS, show that HDS silica differs in the aggregation pattern from classical precipitated silica. These differences in fractal geometry and the differences in surface chemistry provide important clues to the different behaviour of new generations of precipitated silicas performance in rubber compounds. 20 refs. USA

Accession no.759711 Item 110 156th ACS Rubber Division Meeting - Fall 1999. Conference preprints. Orlando, Fl., 21st-23rd Sept.1999, paper 86 SPATIALLY RESOLVED INVESTIGATIONS OF NETWORK STRUCTURE AND CROSSLINK DENSITY OF DIFFERENTLY CURED AND AGED TECHNICAL RUBBERS BY NMR MICROSCOPY Kuhn W; Denner P; Garbaczyk M; Grinberg F; Jurga S IIC Innovative Imaging Corp.KG; Poznan,University; Ilmenau,Technische Universitat; Ulm,University (ACS,Rubber Div.) Crosslink density is a major parameter determining the mechanical properties of technical rubbers. It can be measured spatially resolved by parameter selective 1H NMR imaging and according transformation of NMR parameters such as spin density, relaxation times and diffusion coefficients into materials properties. This transformation is based on the physical understanding of network dynamics. The results provide a detailed understanding of macroscopic properties on the molecular level. To investigate the influence of filler content, different curing conditions and oxidative ageing processes on the dynamics of the rubber network, parameter selective NMR imaging experiments with respect to T1, T2, T1p and the dipolar correlation coefficient QDCE are performed. The interpretation of NMR data is based on a model free approach, the defect diffusion theory and the analysis of the dipolar correlation effect. The results demonstrate clearly the ability of NMR microscopy to determine the network structure and crosslink density of technical rubbers as function of filler content and curing and ageing conditions. They are in good agreement with results obtained by other methods. A detailed picture of the molecular dynamics and microstructure of the network

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is obtained. Using the model free approach or the dipolar correlation effect for the measurement of crosslink density, NMR relaxometry at low magnetic field strength can be used as a tool for quality control in industrial rubber manufacturing processes, providing results rapidly at low costs. 38 refs. EASTERN EUROPE; EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; POLAND; WESTERN EUROPE

Accession no.759681 Item 111 156th ACS Rubber Division Meeting - Fall 1999. Conference preprints. Orlando, Fl., 21st-23rd Sept.1999, paper 85 DENSITY AND SPATIAL DISTRIBUTION OF CROSSLINKS IN PEROXIDE CURED POLYMERS CONTAINING ZINC DIACRYLATE Castner E S; Mallamaci M P Goodyear Tire & Rubber Co. (ACS,Rubber Div.) Scanning-probe microscopy and swelling experiments are employed to characterise the extent of crosslinking and the spatial distribution of crosslinks in peroxide-cured polymers with zinc diacrylate co-curative. The formulations and curing method are similar to those employed throughout the golf ball industry. The application of the Flory-Rehner equation to swelling experiments allows for the qualitative determination of crosslink density in these systems. The scanning-probe microscope is capable of identifying differences in surface modulus with a spatial resolution of several nanometers, which further elucidates the spatial distribution of crosslink density. Factors influencing the extent of participation of the polymers and the zinc diacrylate in the crosslinking process are discussed, such as the partitioning of the peroxide in mixed systems, the difference in reactivity of the peroxide for the two components and the reactivity of radical species. 20 refs. USA

Accession no.759680 Item 112 International Polymer Science and Technology 26, No.7, 1999, p.T/13-5. (Translation of Kauchuk i Rezina, No.2, 1999, p.12) MIGRATION OF MODIFYING COMPONENTS IN VULCANISATES BASED ON SKI-3 POLYISOPRENE AND SKD POLYBUTADIENE RUBBERS Narkhov S N; Shutilin Y F Voronezh,State Technological Academy An investigation was carried out into the migration of modifying agents in vulcanisates based on polyisoprene and polybutadiene. The modifiers used to improve service life were hexachloro-p-xylene, a compound of resorcinol and urotropin, tetramethylthiuram disulphide and

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diphenyl guanidine. With vulcanisates based on polyisoprene, migration processes are found to be more extensive than for those based on polybutadiene. Overall, the experiment showed the occurrence of migration at a distance of up to 20 mm. The mass exchange relationships thus obtained, can be used in the development of products consisting of two parts: an unmodified base and a locally modified working part which undergoes most wear during service. 7 refs. RUSSIA

Accession no.759574 Item 113 156th ACS Rubber Division Meeting - Fall 1999. Conference preprints. Orlando, Fl., 21st-23rd Sept.1999, paper 161 MAGNETIC RESONANCE INSPECTION OF SYNTHETIC RUBBER Skioss T W; Hennessy M J; Pykett I L Intermagnetics General Corp. (ACS,Rubber Div.) Within the past decade, magnetic resonance (MR) technology has become a proven tool for online analysis of industrial processes. Recent measurements suggest that devices capable of inspecting rubber bales (~30 kg) at full production speeds are viable. Analysis of MR relaxation behaviour allows quantitation of the various compounds within a typical bale of rubber. It is demonstrated that concentrations of water in butadienebased rubbers are detectable at levels of less than 0.01% at a magnetic field strength of 0.15T and nominal measurement time of 4 seconds. MR imaging methods may be employed to measure the distribution of dissolved species such as water and oil. The demonstrated performance of a potential online MR analyser for the rubber industry is achieved through the use of permanent magnets, modular electrical components and intelligent automation software. 7 refs. USA

Accession no.759420 Item 114 156th ACS Rubber Division Meeting - Fall 1999. Conference preprints. Orlando, Fl., 21st-23rd Sept.1999, paper 160 REAL-TIME MONITORING OF POLYMERISATION PROCESSES USING A MIDIR FIBREOPTIC PROBE Puskas J E; Michel A J; Brister L B Western Ontario,University (ACS,Rubber Div.) A novel fibreoptic mid-IR probe is developed for the realtime monitoring of polymerisation processes. The probe is equipped with two interchangeable heads: one is an attenuated total reflectance (ATR) head and the other one is a transmission (TR) head. The TR head can monitor

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very low concentrations (0.1 mmol/L). The ATR probe is used to monitor both homogeneous and heterogeneous isobutylene (IB) polymerisations by the disappearance of the C=C double bond stretch at 1655 cm -1 and of the C-H stretch in the CH3- group at 1375 cm -1. Polymer formation is monitored by the appearance of the following signals characteristic of polyisobutylene (PIB): the 1230 cm -1 band identified as the vibrations of the distorted carbon tetrahedrons (-C(CH3)2- groups); the 1364/1391 cm -1 asymmetrical doublet representing the C-H bending of the t-butyl groups; and the 1470 cm-1 methylene ‘scissoring’ vibration. The TR probe is used to monitor the initiation step in a living IB polymerisation initiated by 2-(2,2-dimethyl-propyl)-2-methyl-oxirane (TMPO-1)/ TiCl4. The appearance of bands characteristic of aldehyde/ ketone isomerisation products and polyethers at 1635, 1665 and 1100 cm-1, respectively, is observed in realtime. The disappearance of the C-O-C stretching at 1260 cm-1 can only be monitored in the absence of IB because of overlapping with the 1230 cm-1 band. Due to the sensitivity of the TR probe the 1655 cm-1 band is saturated at the beginning of the polymerisation, so IB consumption is followed by monitoring the 2nd overtone of the =CH2 bending at 1780 cm-1. The results demonstrate the versatility and powerfulness of this new method. 8 refs. CANADA

Accession no.759419 Item 115 156th ACS Rubber Division Meeting - Fall 1999. Conference preprints. Orlando, Fl., 21st-23rd Sept.1999, paper 154 INELASTIC NEUTRON SCATTERING FROM FILLED ELASTOMERS Nakatani A I; Ivkov R; Papanek P; Yang H; Gerspacher M US,National Inst.of Standards & Technology; Pennsylvania,University; Richardson S.,Carbon Co. (ACS,Rubber Div.) Inelastic neutron scattering experiments are powerful techniques for evaluating local molecular dynamics. These methods are especially sensitive to hydrogen atom containing motions. An overview of these experimental techniques is presented and neutron filter analyser and time-of-flight spectroscopy methods are used to characterise the local dynamics of polymers in the presence and absence of fillers. Of particular interest is the comparison between bound rubber attached to the filler surface and the pure, unbound rubber. A commercial synthetic polyisoprene containing approximately 100% cis-1,4 isomers is compounded with three different carbon blacks (N299, G299 (graphitised N299, and N762). Soxhlet extraction is performed on each of the samples so that corresponding samples containing purely bound rubber with filler are obtained. The filter analyser and time-of-flight spectra show distinct differences between the bound and pure rubber as well as differences based

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References and Abstracts

on carbon black type. Correlation of the spectral differences to the type of carbon black and initial concentration of carbon black is discussed. 21 refs.

surface of the carbon black in squalene model systems. The usefulness of these techniques for both real systems and model systems is demonstrated. 16 refs.

USA

EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.759413

Accession no.758351 Item 116 Macromolecules 32, No.22, 2nd Nov.1999, p.7562-71 COMPARATIVE STUDY USING SMALL-ANGLE X-RAY SCATTERING AND SOLID-STATE NMR OF MICRODOMAIN STRUCTURES IN POLY(STYRENE-BUTADIENE-STYRENE) TRIBLOCK COPOLYMERS Hongshi Yu; Natansohn A; Singh M A; Plivelic T Kingston,Queen’s University; Brazil,National Synchrotron Light Laboratory The complementary techniques of solid-state NMR and small-angle X-ray scattering(SAXS) were used to determine the microdomain structures of a series of commercial SBS triblock copolymers with different molec.wts. The relative locations of multiple scattering peaks, indirect transform and Porod analysis were used to determine the morphology and the sizes of various domains as well as the interfacial thickness between them. Solid-state NMR of proton spin diffusion measurements were also used to estimate the microdomain structure parameters by simulating the spin diffusion processes with a model that considered the effects of proton spin-lattice relaxation. The interfacial thickness, 2 nm for all five materials, and the interdomain distances, ranging from 30 to 42 nm, from NMR were in good agreement with results from SAXS techniques. There were some discrepancies for some of the samples with regard to the domain sizes of dispersed PS phases obtained from the above two techniques. These discrepancies could be mainly caused by the limited quality of the fitting procedure using indirect transform methods. 43 refs. BRAZIL; CANADA

Accession no.759211 Item 117 156th ACS Rubber Division Meeting - Fall 1999. Conference preprints. Orlando, Fl., 21st-23rd Sept.1999, paper 57 SURFACE AND FIBRE-RUBBER INTERFACE ANALYSIS BY TOFSIMS AND OTHER TECHNIQUES Van Ooij W J; Kim J-M; Luo S; Borros S Cincinnati,University; Barcelona,Universitat Ramon Llull (ACS,Rubber Div.) Surface analysis techniques, with an emphasis on timeof-flight SIMS, are used to study reactions occurring at the rubber-steel interface in tyres and in squalene model systems, at the textile cord-rubber interface and at the

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Item 118 156th ACS Rubber Division Meeting - Fall 1999. Conference preprints. Orlando, Fl., 21st-23rd Sept.1999, paper 24 TEM OBSERVATION OF NATURAL RUBBER THIN FILMS CRYSTALLISED UNDER MOLECULAR ORIENTATION Shimizu T; Tosaka M; Tsuji M; Kohjiya S Kyoto,University (ACS,Rubber Div.) Morphology of NR thin films crystallised under molecular orientation is examined by transmission electron microscopy (TEM). A thin film of NR (RSS1) is made by casting its n-hexane (or benzene) solution onto the water surface, and prestretched by a desired amount of strain e (%) up to 800%. Each of the specimens thus prepared is introduced into a TEM column and crystallised at isothermally -25 deg.C with a cryo-transfer specimenholder. Morphological observations in bright- and darkfield imaging modes reveal directly that the length of the lamellae, which are oriented perpendicular to the stretching direction, decrease with increasing E. The result seems to be related to the population density of ‘gammafilaments’ generated only by prestretching. Time-resolved bright-field observation by in situ TEM of the thin film prestretched by E = 200% reveals the following: although the film gives crystalline reflections in its selected-area electron diffraction even before isothermal crystallisation, no well-defined lamellae are recognised; subsequent isothermal crystallisation for 2 h, however, can form welldefined lamellae oriented perpendicular to the stretching direction. This observation suggests that gamma-filaments are formed immediately by prestretching and then the lamellae are nucleated on the gamma-filaments at -25 deg.C. 28 refs. JAPAN

Accession no.758322 Item 119 Polymer 41, No.1, 2000, p.323-34 RADIATION DEGRADATION OF MG RUBBER STUDIED BY DYNAMIC MECHANICAL ANALYSIS AND SOLID-STATE NMR Perera M C S; Rowen C C Griffith University Methyl methacrylate-grafted natural rubber (NR) was prepared by the free radical polymerisation of methyl methacrylate in NR latex, and then subjected to high-

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energy radiation. The changes occurring were studied using dynamic mechanical analysis and solid-state nuclear magnetic resonance spectroscopy. More extractable poly(methyl methacrylate) (PMMA) was formed during the exposure. This was attributed to chain scission of the PMMA molecules. The interfacial region disappeared during irradiation, and phase separation occurred as a consequence of the loss of the grafted polymer which acted as a compatibiliser. The radiation yield of crosslinking and scission in NR and PMMA, respectively, calculated from glass transition temperature data, was comparable to that of the homopolymers irradiated separately. A cis-trans isomerisation of polyisoprene occurred during the irradiation, the peaks being observed in the NMR spectra. 38 refs. AUSTRALIA

Accession no.757136 Item 120 Polymer International 48, No.10, Oct.1999, p.1035-41 STRUCTURE DEVELOPMENT IN SILICAFILLED RUBBER COMPOSITES Ono S; Kiuchi Y; Sawanobori J; Ito M Tokyo,Science University Structure development in silica-filled polyisoprene was investigated using wide line pulsed NMR and highresolution solid-state NMR, combined with transmission electron microscopy. The rubber phase consisted of bound rubber and free rubber, the bound rubber consisting of multiple phases with different mobilities. The amount of bound rubber and its mobility were determined by the type of silica used. There was negligible bonding between silanol groups and rubber molecules, the principle mechanism forming the bound rubber was physical adsorption of rubber molecules onto the silica surface. The amount of bound rubber was affected by the state of aggregation of the silica particles, which in turn was determined by the particle size and the concentration of silanol groups on the particles. The amount of bound rubber, and the chemical structure of the polyisoprene, changed with heat treatment. It was concluded that the increase of bound rubber with heat treatment was due to the development of chemical crosslinks in both the bound and the free rubber phases. 21 refs. JAPAN

Accession no.756184 Item 121 Macromolecules 32, No.19, 21st Sept.1999, p.5994-7 QUANTITATIVE ANALYSIS OF SEQUENCE LENGTH DISTRIBUTION OF 1,2 UNITS IN POLYBUTADIENES BY OZONOLYSIS-GPC METHOD Kakuta K; Tamai H; Wong P-H; Kawahara S; Tanaka Y

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Tokyo,University of Agriculture & Technology; Nagaoka,Technological University The sequence distribution of 1,2 units in a variety of polybutadienes was determined by gel permeation chromatography (GPC) analysis of ozonolysis products. Ozonides from the polybutadiene were converted to trifluoroacetates by reduction with lithium aluminium hydride, followed by esterification with trifluoroacetic anhydride. The trifluoroacetates derived from 1,4-1,4- and 1,4-(1,2)n-1,4 sequences, where n is 1 to 7, were observed as GPC peaks using a refractive index detector. The concentration of each sequence was determined from the relative peak intensities using correction factors determined using model compounds and by direct weighing of each peak. Polybutadienes prepared by anionic polymerisation had a sequence distribution of 1,2 and 1,4 units corresponding to Bernoullian statistics, whereas the 1,4-(1,2)n-1,4 sequence was significantly higher than the theoretical value for 1,2 units in cis-1,4 polybutadiene. 17 refs. JAPAN

Accession no.756049 Item 122 Journal of Applied Polymer Science 74, No.11, 9th Dec.1999, p.2625-30 RHEOLOGICAL CHARACTERISATION OF ETHYLENE VINYL ACETATE COPOLYMERS Arsac A; Carrot C; Guillet J Laboratoire de Rheologie Using various analytical techniques including size exclusion chromatography to determine molecular weight distribution, differential scanning calorimetry to study melting point and dynamic mechanical spectroscopy to study glass transition temperature, samples of ethylene vinyl acetate containing between 5 and 40 weight percent of vinyl acetate were characterised. It was shown that glass transition temperature was almost independent of composition, and that rheological behaviour in the molten state is much more dependent on molecular weight distribution and branching rather than on chemical composition. A unique set of Williams Landel Ferry (WLF) coefficients is indicated. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.756003 Item 123 Journal of Rubber Research 2, No.3, 3rd Quarter, 1999, p.150-9 NR LATEX PARTICLE SIZE AND ITS MOLECULAR WEIGHT FROM YOUNG AND MATURE HEVEA TREES Kovuttikulrangsie S; Tanaka Y Prince of Songkla University; Tokyo,University of Agriculture & Technology

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References and Abstracts

The age of young Hevea trees was shown to affect the size of latex particles. Young seedling trees less than 3 years old had small rubber particles of size less than 1 micrometre, while mature trees showed particle sizes up to 4 micrometres. NR latex particles from virgin trees of clones RRIM 600, aged from 1 to 7 years, showed average particle size distribution of about 0.30 to 0.65 micrometre. The weight-average molec.wt. increased dramatically from 330,000 to 1,200,000. The polydispersity or MWD of rubber was extremely wide, between 3 and 10. Different clones of 25 year old regularly tapped trees exhibited mode average particle sizes of about 1.0 micrometre. The number-average molec.wt. was from about 670,000 to 3,000,000 and the polydispersity was very extensive between 5 and 11. 6 refs. JAPAN; THAILAND

Accession no.755912 Item 124 Journal of Thermal Analysis and Calorimetry 56, No.3, 1999, p.1107-13 DSC ANALYSIS OF THE INDUCTION PERIOD IN THE VULCANISATION OF RUBBER COMPOUNDS Simon P; Kucma A Slovak,Technical University; Slovak Republic,Rubber Research Institute Vulcanisation of rubber compounds was studied by DSC under isothermal and non-isothermal conditions. The parameters of an Arrhenius-like equation describing the temp. dependence of induction period were obtained both from isothermal and non-isothermal measurements. A new method for obtaining the kinetic parameters from nonisothermal measurements, based on the dependence of onset temp. of vulcanisation peak on heating rate, is presented. A procedure for the evaluation of temp. difference between the furnace and sample is proposed. It was shown that the treatment of non-isothermal DSC measurements gave the kinetic parameters free of systematic errors. The method could also be used for studying other reactions exhibiting the induction period. 8 refs. SLOVAK REPUBLIC; SLOVAKIA

Accession no.755851 Item 125 Elastomery 3, No.4, 1999, p.28-33 REINFORCEMENT OF ELASTOMERS: EFFECT OF POLYMER/FILLER INTERACTIONS ON THE DYNAMICS OF ELASTOMERIC CHAINS AT THE INTERFACE Vidal A; Haidar B CNRS-ICSI Detailed information obtained on the structure and properties of the interphase between a filler and an

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elastomeric matrix from studying molecular dynamics of polymer chains in elastomer/filler blends is presented. It was found that the interactions which take place at the polymer/filler interface are selective and dependent on the filler/polymer couple being studied. Dynamic mechanical testing, differential scanning calorimetry, relaxational behaviour and solid state NMR were reported to have been used to obtain information. 13 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.755222 Item 126 Journal of Polymer Science: Polymer Chemistry Edition 37, No.16, 15th Aug.1999, p.3129-38 SYNTHESIS AND CHARACTERIZATION OF HIGH MOLECULAR WEIGHT CARBOXYLATED POLYBUTADIENE Gong L; Wool R P; Friend A D; Goranov K Delaware,University; Illinois,University High molecular weight carboxylated polybutadienes were synthesised by the hydrocarboxylation of polybutadienes (PBD) at 140-150 C using PdCl2(PPh3)2 and SnCl2.2H2O catalysts. Number-average molecular weights of 98000200000, and carboxylic acid contents of 0.5-10 mol% were achieved. At low levels of hydrocarboxylation, there was little change in the glass transition temperature, and significant chain scission and crosslinking were not detected. Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and Raman spectroscopy showed that the carboxylic groups were incorporated on the pendant (1,2) PBD double bonds as well as the backbone (1,4) double bonds, suggesting that the hydrocarboxylation reaction did not just occur at the terminal carbons of the pendant double bonds. 32 refs. USA

Accession no.753396 Item 127 Kunststoffe Plast Europe 89, No.8, Aug.1999, p.27-8 English; German QUALITY ASSURANCE THROUGH COUPLING TGA AND FTIR Hoffmann F Mettler-Toledo GmbH The decomposition behaviour of rubbers can be determined in both quantitative and qualitative terms by coupling thermogravimetry (TGA) and IR spectroscopy (FTIR). This makes it possible to compare materials with a high level of reproducibility. (Translated from Kunststoffe p.82-4). EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.753244

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Item 128 Rubber Chemistry and Technology 72, No.1, March-April 1999, p.165-173 STUDIES OF ELASTOMER OXIDATION VIA THERMAL ANALYSIS Burlett D J Goodyear Tire & Rubber Co. Prepared samples of polybutadiene with differing vinyl levels were treated with different antioxidants and subjected to analysis using differential scanning calorimetry, from which activation energies of the oxidative process could be determined, and fourier transform infra red from which the chemistry of the oxidative process could be determined. Both isothermal and dynamic scanning techniques were used on the DSC. Activation energies were compared with familiar 1 per cent oxygen absorption figures. (Paper originally presented to ACS Indianapolis meeting May 5-8,1998, revised July 1998) 10 refs USA

Accession no.753131 Item 129 Rubber Chemistry and Technology 72, No.1, March-April 1999, p.109-118 ENCAPSULATION IN TERNARY ELASTOMER BLENDS Yasuaki Koseki; Moo Sung Lee; Macosko C W Toyobo Research Center; Minnesota,University Transmission Electron Microscopy was used to study a ternary blend of NBR, Chlorinated Polyethylene and EP rubber. Different encapsulation effects were noted depending on the chlorine content of the chlorinated polyethylene and the acrylonitrile content of the NBR where different grades of these materials were used in a fixed blend ratio with EP rubber. Interpretation of the results used solubility parameter, melt viscosity differences in the NBR and CM, and a spreading coefficient concept. In general the CM was seen to encapsulate the NBR in the EP matrix, but for particular blends the opposite encapsulated structure was observed which was not always in agreement with predictions. 29 refs JAPAN

Accession no.753126 Item 130 Journal of Applied Polymer Science 74,No.3, 17th Oct.1999, p.490-501 APPLICATION OF THERMOMECHANICAL MASS SPECTROSCOPY FOR ANALYSIS OF MOLECULAR AND TOPOLOGICAL STRUCTURE OF RUBBER Jurkowska B, Olkhov Y A,Jurkowski B STOMIL; Russian Academy of Sciences; Poznan,University of Technology

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A novel method is applied to study the topological and molecular structures of multi-component rubber. This method is based on the thermomechanical analysis of a solid polymer. A diblock amorphous structure is found for the studied rubber network. These blocks differ a great deal in their glass transition temperature. The methodology of how to calculate the crosslink density in each block, the molecular weight distribution of the chains between the junctions of the network and the shares of low-temperature (soft) and high-temperature (hard) blocks in a structure of the rubber network are also shown. Based on these data it is possible to calculate the number-average and weight-average molecular weight and the polydispersity coefficients of the chains between the junctions of the network. 30 refs. EASTERN EUROPE; POLAND; RUSSIA

Accession no.752303 Item 131 Kautchuk und Gummi Kunststoffe 52, No.10, Oct.1999, p.663-9 ADVANCES IN EPDM TECHNOLOGY. STRUCTURE DETERMINATION AS A KEY TO IMPROVED PRODUCT PERFORMANCE AND CONSISTENCY Meijers P W L J; Maag L R; Beelen H J H; Van de Nen P M DSM Elastomers NV Details are given of an analytical method developed by DSM for the quantification of the level of long chain branching in new-generation grades of EPDM. Using this method, by means of dynamic mechanical spectrometry, a rheological fingerprint of the EPDM polymer structure is obtained, and from which the level of long chain branching can be derived. However, the method is of limited use in a production environment, and therefore, the Mooney Stress Relaxation test has been studied as an alternative method for quantifying polymer structure in terms of controlled long chain branching. 12 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.751760 Item 132 Polymer 40, No.25, 1999, p.7013-7 OBSERVATION OF IMMOBILE REGIONS IN NATURAL RUBBER AT AMBIENT TEMPERATURE BY SOLID-STATE 13C CP/MAS NMR SPECTROSCOPY Larsen F H; Rasmussen T; Pedersen W B; Nielsen N C; Jakobsen H J Aarhus,University; West Company A/S; Riso National Laboratory The existence of immobile regions in NR (Neorub, SMR CV60) corresponding to a few percent of the monomer

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References and Abstracts

units was detected at ambient temp. using carbon-13 cross-polarisation/magic angle spinning NMR spectroscopy. For synthetic rubbers (Natsyn 2200, Cariflex IR), no immobile regions were detected at all. By application of different physical and chemical treatments to NR, it was shown that mastication, gammairradiation and increasing the temp. slightly above the ambient temp. reduced the amount of immobile regions. 27 refs. DENMARK; EUROPEAN COMMUNITY; EUROPEAN UNION; SCANDINAVIA; WESTERN EUROPE

gel fraction of the particles were lower than those of the granulates, and were further reduced by reprocessing. Thermal analysis revealed similar behaviour of particles and granulates in a nitrogen environment, but there was considerable thermooxidative degradation of fine particles in air. Chemical analysis showed that some of the bonds were broken during pulverisation and that partial devulcanisation had taken place. 25 refs. USA

Accession no.749895

Accession no.751688 Item 133 Journal of Applied Polymer Science 74, No.5, 31st Oct.1999, p.1250-63 POLYISOPRENE, POLY(STYRENECOBUTADIENE), AND THEIR BLENDS. I. VULCANIZATION REACTIONS WITH TETRAMETHYLTHIURAM DISULFIDE/ SULFUR Mallon P E; McGill W J Port Elizabeth,University Polyisoprene(IR), SBR and their blends were vulcanised with TMTD/sulphur in a differential scanning calorimeter at a programmed heating rate and isothermally in a press at 130C. IR was found to crosslink more rapidly than SBR, the difference being attributed to the greater reactivity of the accelerator polysulphides in the initiating reaction with IR than with SBR. In blends, the greater reactivity of IR led to the earlier crosslinking of IR, the depletion of curing agents in the IR phase and the diffusion of curing agents from SBR to IR. A zone of highly crosslinked material thus developed in IR close to the interface. 34 refs.

Item 135 155th ACS Rubber Division Meeting, Spring 1999. Conference Preprints. Chicago, Il., 13th-16th April 1999, Paper 73, pp.26 ANALYTICAL PROPERTIES OF SILICA: A KEY FOR UNDERSTANDING SILICA REINFORCEMENT Blume A Degussa-Huels AG (ACS,Rubber Div.) A number of silicas were characterised for particle size distribution, specific silanol group density, surface activity and dispersion coefficient, and relationships between these filler properties and the performance of tyre tread compounds were investigated. Effects on rheological and mechanical properties and cure rate were examined, and parameters for the improvement of dispersion, dynamic stiffness and vulcanisation behaviour were identified. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; USA; WESTERN EUROPE

Accession no.749885

SOUTH AFRICA

Accession no.751466 Item 134 155th ACS Rubber Division Meeting, Spring 1999. Conference Preprints. Chicago, Il., 13th-16th April 1999, Paper 85, pp.28 ANALYSIS OF RUBBER PARTICLES PRODUCED BY THE SOLID STATE SHEAR EXTRUSION PULVERIZATION PROCESS Bilgili E; Arastoopour H; Bernstein B Illinois,Institute of Technology (ACS,Rubber Div.) Vulcanised NR granulates were pulverised by a solid state shear extrusion process, and the resulting particles were studied by physical, chemical and thermal analyses. Reprocessing of the powder resulted in narrower particle size distribution, and heat generated in the extruder caused surface oxidation and agglomeration of the particles. The particles had irregular shapes and rough surfaces and showed surface porosity, but no microporosity was detected by nitrogen BET analysis. Crosslink density and

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Item 136 155th ACS Rubber Division Meeting, Spring 1999. Conference Preprints. Chicago, Il., 13th-16th April 1999, Paper 40, pp.24 APPLICATIONS OF ULTRA-HIGH RESOLUTION EVANESCENT MICROWAVE IMAGING PROBE IN TIRE AND RUBBER MEASUREMENTS Tabib-Azar M; Mowdood S K; LeClair S Case Western Reserve University; Pirelli Tire LLC; US,Air Force Research Laboratory (ACS,Rubber Div.) The use of evanescent microwave probes for imaging non-uniformities in a variety of materials is discussed. Applications of this technique are illustrated by a number of examples, including the study of the surface structure of EPM samples and damage detection in tyres. 25 refs. WRIGHT-PATTERSON AIR FORCE BASE USA

Accession no.749856

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References and Abstracts

Item 137 155th ACS Rubber Division Meeting, Spring 1999. Conference Preprints. Chicago, Il., 13th-16th April 1999, Paper 30, pp.12 CHEMICALLY SENSITIVE IMAGING OF TIRE BLENDS USING X-RAY MICROSCOPY Dias A J; Urquhart S G; Ade H; Smith A P; Stevens P Exxon Chemical Co.; North Carolina,State University; Exxon Research & Engineering Co. (ACS,Rubber Div.)

(ACS,Rubber Div.) Emulsion SBR was prepared by blending high and low molecular weight polymers with different styrenebutadiene compositions, and the blends were characterised by a combination of analytical and rheological methods. A two-phase co-continuous morphology was observed by scanning probe microscopy when the bound styrene difference between the two components was greater than 18%, consistent with the two Tg’s measured by modulated DSC. Blending also reduced the amount of very high molecular weight material observed in conventional emulsion polymers by thermal field-flow fractionation. This technique was superior to size exclusion chromatography for fully characterising the molecular weight and MWD of the polymers. Time temperature superposition was used to characterise the viscoelastic behaviour in the rubbery platean and terminal zones. 21 refs.

Results are presented of experiments in which scanning transmission X-ray microscopy and near edge X-ray absorption fine structure spectroscopy were used in the morphological characterisation of tyre compounds based on blends of a brominated isobutylene-methylstyrene copolymer and polybutadiene, and in the study of the distribution of carbon black and silica fillers in the blends. 7 refs.

USA

USA

Accession no.749829

Accession no.749847 Item 138 155th ACS Rubber Division Meeting, Spring 1999. Conference Preprints. Chicago, Il., 13th-16th April 1999, Paper 19, pp.16 FEASIBILITY OF DETERMINING THE AMOUNT OF OIL IN STYRENE-BUTADIENE TYPE RUBBER BY PULSED NMR SPECTROSCOPY Ghebremeskel G N; Westendorf N; Hendrix C Ameripol Synpol Corp. (ACS,Rubber Div.) NMR spectroscopy using a spin echo was applied to determining the amount of oil in SBR and polybutadiene extended with aromatic and naphthenic oils. The measurement was based on the markedly different relaxation rates of the polymer and oil phases of the samples. The combined signal of the two phases was obtained by sampling the free induction decay following a 90 degree pulse in a spin echo sequence. The signal echo representing the oil phase was measured when the solid phase signal decayed to a negligible value. The oil content values obtained by this method were in good agreement with those obtained by solvent extraction. 6 refs.

Item 140 155th ACS Rubber Division Meeting, Spring 1999. Conference Preprints. Chicago, Il., 13th-16th April 1999, Paper 5, pp.33 MANUFACTURE OF EPDM WITH CONSISTENT POLYMER AND COMPOUND RHEOLOGY Wortman W A; Beardsley K P; Caldwell J D Uniroyal Chemical Co. (ACS,Rubber Div.) GPC, Mooney relaxation and dynamic mechanical analysis were evaluated as quality control techniques in EPDM production. Three vanadium catalysed polymers of similar Mooney viscosity but varying in degree of branching were characterised to demonstrate the sensitivity of these tests to structure, and the same methods were applied to a series of 12 consecutive production lots of EPDM. Compound processability and cure characteristics were studied, cured compound samples were tested for carbon black dispersion, and the rheological properties of raw polymer samples were compared to those of compounded samples. Vanadium based catalyst systems were shown to be capable of producing EPDM with very consistent rheology. 8 refs. USA

Accession no.749823

USA

Accession no.749836 Item 139 155th ACS Rubber Division Meeting, Spring 1999. Conference Preprints. Chicago, Il., 13th-16th April 1999, Paper 11, pp.32 NEW EMULSION SBR TECHNOLOGY. I. RAW POLYMER STUDY Lewandowski L; Sibbald M; Johnson E; Mallamaci M Goodyear Tire & Rubber Co.,Chemicals Div.

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Item 141 Journal of Applied Polymer Science 73, No.13, 23rd Sep.1999, p.2779-81 INTERFACIAL REACTION OF STANNIC OXIDE IN SILICONE RUBBER AT 300 C Zhengtao Su Beijing,Institute of Aeronautical Materials The thermal stability of vulcanised silicone rubber, containing stannic oxide as a heat stabiliser, was

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References and Abstracts

investigated by ageing the rubber at 300 C for 24 hours in air, followed by analysis using X-ray photoelectron spectroscopy. The Sn was reduced during vulcanisation and heat ageing, which contributed to the thermal stability of the vulcanised rubber. 4 refs. CHINA

Accession no.747731 Item 142 Journal of Applied Polymer Science 73, No.13, 23rd Sep.1999, p.2587-93 MIGRATION BEHAVIORS OF WAX TO SURFACE IN RUBBER VULCANIZATES Choi S-S Kumho R & D Center The migration behaviour of wax, a mixture of normal alkanes and their isomers, in carbon black-filled natural rubber (NR), styrene-butadiene rubber (SBR), and butadiene rubber (BR) was evaluated at 60 and 80 C over a period of 14 days. The migration behaviour was similar to the evaporation behaviour, the amount of wax migrating to the surface and evaporating at 80 C decreased with increasing molecular weight of the normal alkanes. The migration in NR was influenced more by the molecular weight of the alkanes than it was in SBR and BR. The major factors influencing the migration behaviour of the wax are discussed in conjunction with structure calculations and wax evaporation experiments. 15 refs. KOREA

Accession no.747712 Item 143 Revista de Plasticos Modernos 77, No.515, May 1999, p.529-35 Spanish EFFECT OF PLASTICISERS ON THE MICROSTRUCTURE AND CONDUCTIVE PROPERTIES OF EPDM BASED IONOMERS Bashir H; Linares A; Acosta J L Instituto de Ciencia y Tecnologia de Polimeros Membranes for use in fuel cells were prepared from sulphonated EPDM ionomers containing paraffin oil, butyl phthalate or non-sulphonated EPDM plasticisers, and the influence of these plasticisers on the microstructure and electrical properties of the ionomers was investigated. Degree of sulphonation was studied by X-ray photoelectron spectroscopy, microstructure by DSC and DMA, and conductivity by complex impedance spectroscopy. The plasticisers displaced the Tg towards lower temperatures, improving processability and dimensional stability. The conventional plasticisers adversely affected conductivity due to the inhibition of hydration, while samples plasticised with EPDM showed considerably higher conductivity as a result of increased hydration. 6 refs.

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EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.745774 Item 144 China Synthetic Rubber Industry 22, No.4, 1999, p.210-2 Chinese STUDY ON RELATIVE MOLECULAR MASS DISTRIBUTION OF LOW CIS-1,4POLYBUTADIENE RUBBER BY GPC Li Y; Xiushan H; Xinghao Z Jilin Chemical Group Corp. The relative molecular mass distribution of low cis-1,4polybutadiene rubber (LCBR) was studied by GPC. The LCBR of Japan Asaprene 730 A was defined as 4 star branched polymer. LCBR was synthesised by coupling polymerisation and pilot plant test was guided by the distribution curves of GPC. 6 refs. CHINA

Accession no.742883 Item 145 Applied Spectroscopy 53, No.5, May 1999, p.547-50 ANALYSIS OF ODOROUS VAPOUR EXHALED FROM RUBBER BY SURFACE-ENHANCED RAMAN SCATTERING Hill W; Wehling B; Klockow D Germany,Institut fuer Spektrochemie & Angewandte Spektroskopie Vulcanised rubber evolves an evil-smelling gas for months after contact with the fumigant methyl bromide. Analysis of the gas by surface-enhanced Raman scattering (SERS) shows that it contains traces of a thiomethyl compound, identified as methyl mercaptane. SERS can be used to determine gas-phase concentrations of methyl mercaptane in the low ppbv range by analysing the velocity of adsorption. The investigated sample demonstrates the capability of SERS for the detection and identification of very low gas concentrations of substances that are adsorbed irreversibly at silver surfaces. 13 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.740337 Item 146 ACS, Polymeric Materials Science and Engineering. Vol.76. Conference proceedings. San Francisco, Ca., Spring 1997, p.193. 012 SOLID-STATE 13C NMR STUDIES OF CHANGES IN CROSSLINKED CARBON STRUCTURE DURING HEATING UNDER AIR AND NITROGEN ENVIRONMENTS Parker D D; Koenig J L

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Case Western Reserve University (ACS,Div.of Polymeric Materials Science & Engng.) The degradation of NR can be caused by different factors including elevated temperature and oxidation. 13C NMR has previously been used to examine the concentration of the different crosslinked structures, 13C-Sx-13C and the trans isoprene isomer in the range of 1070ppm. The changes in the concentration of the different C-Sx-C crosslink structures under thermo-oxidative conditions are examined. Unfilled NR is sulphur vulcanised to 100% cure using t-butylbenzothiazole sulphenamide (TBBS) as accelerator. The rubber in 2 mm thick sheets is extracted with chloroform to remove vulcanisation compounds and then heated at 100 and 150 deg.C under both air (oxygen) and nitrogen environments with samples taken at different time intervals. The samples are examined on a Bruker MSL 300 instrument with a CP/MAS probe using magic angle spinning at 3500 kHz. Peak areas are determined using a Biorad Win-LR software program. 2 refs. USA

Accession no.737972 Item 147 Polymer Degradation and Stability 64, No.2, May 1999, p.197-205 INFLUENCE OF CURE AND CARBON BLACK ON THE HIGH TEMPERATURE OXIDATION OF NATURAL RUBBER. I. CORRELATION OF PHYSICO-CHEMICAL CHANGES Edge M; Allen N S; Gonzalez-Sanchez R; Liauw C M; Read S J; Whitehouse R B Manchester,Metropolitan University; Cabot Corp. The thermooxidative stability of NR was studied at 150C as a function of the cure process (sulphur, sulphurless or peroxide curing) and the properties of the carbon black filler (five different carbon blacks were used). The thermooxidation was followed by iodometric analysis of hydroperoxide levels, FTIR spectroscopy and differential thermal analysis. The results were discussed and they showed that the type of curing system had an effect on the degradation profile, but the surface reactivity and structure of the carbon black had a controlling role in each system.13 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; USA; WESTERN EUROPE

Accession no.737341 Item 148 Nippon Gomu Kyokaishi 72, No.1, 1999, p.37-42 Japanese OBSERVATION OF THE DISPERSION OF SILICA IN SILICONE RUBBER Kobayashi Y; Hori Y; Aoki T Tokuyama Corp.

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Specimens of silica-dispersed silicone rubber were prepared by modified freeze fracture, and scanning electron microscopy was applied for observation of the dispersion of the silica. 7 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.735066 Item 149 China Synthetic Rubber Industry 22, No.3, 1999, p.178 FLUORESCENCE STUDIES OF ASSOCIATION BEHAVIOUR OF SBS MICELLES Peijun J; Jian X; Meiling Y; Lianghe S Chinese Academy of Sciences Fluorescence spectroscopy has been applied to the study of the molecular structure of styrene-butadiene-styrene block copolymer micelles. These micelle systems have potential applications in many areas including surface modification and drug delivery. The process of SBS micelle formation by fluorescence is studied. 3 refs. CHINA

Accession no.734403 Item 150 International Polymer Science and Technology 25, No.10, 1998, p.23-5 REACTION OF SULPHENAMIDE ACCELERATORS WITH SULPHUR UNDER TEMPERATURE CONDITIONS MODELLING THE VULCANISATION SCHEDULE Tarasov D V; Vishnyakov I I; Grishin B S Results are reported of a study of the thermochemical processes occurring under temp. conditions similar to vulcanisation schedules with N-oxydiethylene-2benzthiazyl sulphenamide and N-cyclohexyl-2benzthiazyl sulphenamide and their mixtures with sulphur. Experiments were carried out using a chromato-mass spectrometer and a TGA-DTA thermal analyser. The formation of high molec.wt. polysulphides in the thermolysis products of sulphenamides with sulphur at vulcanisation temps. was established. 3 refs. (Full translation of Kauch.i Rezina, No.5, 1991, p.39) RUSSIA

Accession no.733369 Item 151 Journal of Polymer Science: Polymer Physics Edition 37, No.11, 1st June 1999, p.1095-103 PSEUDOHEXAGONAL CRYSTALLINITY AND THERMAL AND TENSILE PROPERTIES OF ETHENE-PROPENE COPOLYMERS Guerra G; Ruiz de Ballesteros O; Venditto V; Galimberti M; Sartori F; Pucciariello R

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References and Abstracts

Salerno,University; Montell Polyolefins; Basilicata,University Structural, melting and mechanical characterisations on uncrosslinked ethylene-propylene copolymers samples, obtained using a metallocene-based catalytic system and having an ethylene content in the range 80 to 50 mol % were conducted by X-ray diffraction, DSC and tensile testing, respectively. Samples with an ethylene content in the range 80 to 60 mol % presented a disordered pseudohexagonal crystalline phase, whose melting moved from about 40C down to about -20C as the ethylene content was reduced. The marked effect of the crystalline phase on tensile properties of uncrosslinked ethylenepropylene copolymers was shown. In particular, the highest EB values were obtained for samples being essentially amorphous in the unstretched state and partially crystallising under stretching. The lowest tension set values (most elastic behaviour) were observed for samples exhibiting, already in the unstretched state, microcrystalline domains acting as physical crosslinks in a prevailing amorphous phase. 53 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.733337 Item 152 Materiaux & Techniques 86, Nos.9/10, Sept./Oct.1998, p.59-61 TESTING AND ANALYSIS OF RUBBER-TOMETAL BONDED PARTS Jacks J Acadia Polymers Inc. The shortcomings of techniques such as Fourier transform IR spectroscopy and energy dispersive X-ray analysis in the study of failure in rubber-to-metal bonded parts are discussed. Results are presented of a study in which SEM and X-ray photoelectron spectroscopy were used in the failure analysis of a rubber-to-steel bonded component which had failed after exposure to hydrocarbon oil at 150C. The results suggested premature curing of the adhesive as the most likely cause of failure. USA

Accession no.732508 Item 153 Rubber Chemistry and Technology 71, No.4, Sept-Oct. 1998, p.766-77 NITROSAMINE FORMATION IN RUBBER. II. INFLUENCE OF CURE Willoughby B G; Scott K W Rapra Technology Ltd. Details are given of nitrosamine formation in twenty-nine different EPDM cures. Both ingredient and processrelated effects were investigated. Two different levels of tetramethylthiuram disulphide and carbon black were

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variables in this study, as was the type of carbon black used. Batch effects with respect to both polymer and carbon black were also studied as was the presence or absence of mercaptobenzothiazole. 14 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.730170 Item 154 International Polymer Science and Technology 25, No.9, 1998, p.T/37-9 INFLUENCE OF DIFFUSION OF MODIFIER RU1 FROM THE CARCASS INTO THE BREAKER OF A CAR TYRE ON THE RUBBER-TO-METAL CORD BOND STRENGTH Shmurak I L Russia,Scientific Research Institute of the Tyre Industry The radial car tyre which was studied had the breaker reinforced with brass-coated metal cord (4L22) and contained modifier RU-1 (resorcinol-containing adhesion promoter) initially in the carcass rubber. Diffusion into the breaker of the tyre was confirmed by the colour reaction between resorcinol-containing compounds and iron (III) chloride. Model systems as well as real tyre specimens were studied. Rubber-cord adhesion was tested by the H method. The results confirmed the reduction in the bond strength of metal cord to breaker rubber under the influence of RU-1 conversion products diffusing from the carcass rubber. A degradation mechanism involving breakdown of copper-sulphur bonds by ammonia is proposed. Reduction in bond strength can be avoided by replacing the hexamethylene tetramine component of modifier RU-1 with hydroxymethyl derivatives of melamine, which do not detach ammonia, or by adding substances to the rubber mix that contain an epoxy or an isocyanogen group. Rubbers involved were synthetic polyisoprene and NR. 14 refs. RUSSIA

Accession no.729165 Item 155 Journal of Polymer Science : Polymer Physics Edition 37, No.8, 15th April 1999, p.859-66 NANO-DEFORMATION OF CRYSTALLINE DOMAINS DURING TENSILE STRETCHING STUDIED BY ATOMIC FORCE MICROSCOPY McLean R S; Sauer B B Du Pont de Nemours E.I.,& Co.Inc. Pebax segmented PU elastomers were solvent-cast onto glass microscope slides from 0.1 wt % solutions for the thin films (20-50 nm) and 7 wt % solutions for thick films (10-50 micrometres). Films were slowly peeled off the glass, stretched to the desired extension and laid back down on the glass while retaining the stretch. Atomic force microscopy was then used to study the films. The results

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obtained are discussed with reference to the nanodeformation of crystalline domains. 46 refs. ATOCHEM INC.

blends which are in current use. Materials are indexed under both polymer and trade name. Accession no.725345

USA

Accession no.727123 Item 156 International Polymer Science and Technology 25, No.7, 1998, p.87-95 STRUCTURAL CHARACTERISATION OF ELASTOMERS BY X-RAY SCATTERING METHODS Murakami T; Murakami S; Ikeda Y A review of the literature on the structural analysis of elastomers by wide-angle and small-angle X-ray scattering methods is presented. Modern X-ray measurement systems are described, with particular reference to the imaging plate and the position-sensitive proportional counter. The structural analysis of polymer gels by small-angle X-ray scattering is described and the structural analysis of ionic elastomers by X-ray scattering methods is considered. 39 refs. (Full translation of Nippon Gomu Kyokaishi, No.3, 1998, p.129) JAPAN

Accession no.727061 Item 157 Gummi Fasern Kunststoffe 51, No.12, Dec.1998, p.958-64 German DISPERSION MONITORING IN RUBBER PRODUCTION Andersson L O; Persson S; Skoog L Optigrade AB The authors discuss the Reflected Light Method for monitoring the dispersion of fillers in rubber compounds. 10 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.726948 Item 158 Shawbury, Rapra Technology Ltd., 1997, pp.315. 220.00. 30cms. 9922 RAPRA COLLECTION OF INFRARED SPECTRA OF RUBBERS, PLASTICS AND THERMOPLASTIC ELASTOMERS. SECOND EDITION Sidwell J A This book provides a set of transmission and pyrolysate spectra of a comprehensive range of technically important rubber and plastics materials including copolymers and

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Item 159 European Polymer Journal 35, No.4, April 1999, p.743-9 STUDY OF THE MICROSTRUCTURE AND THERMAL PROPERTIES OF TETRAFLUOROETHYLENE-PROPYLENE ELASTOMERS Kostov G; Bessiere J M; Guida-Pietrasanta F; Bauduin G; Petrov P Bourgas,University; Montpellier,Ecole Nationale Superieure de Chimie The above elastomers, containing from 41 to 53 mol % tetrafluoroethylene, were prepared by emulsion copolymerisation in batch operation, initiated by a redox system with tert-butylperoxybenzoate. Alternating copolymers with a wide range of monomer compositions were obtained. The composition curve had one azeotropic point at 46.7 mol % tetrafluoroethylene(TFE). The reactivity ratio calculated from NMR and elemental analysis was found to be r(TFE) 0.014 and r(propylene) 0.18. Highly alternating structures of the copolymers synthesised were proved. Copolymer compositions calculated from NMR spectra corresponded to those obtained by elemental analysis. The thermal properties were measured by DSC and TGA and discussed in relation to the copolymer structure. 25 refs. BULGARIA; EASTERN EUROPE; EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.725220 Item 160 Kautchuk und Gummi Kunststoffe 52, No.2, Feb.1999, p.124-33 German CRITICAL COMPARISON OF GC AND HPLC IN THE ANALYSIS OF RUBBER COMPOUNDS Stein G; Wunstel E; Held C Wiesbaden,Fachhochschule Methanolic extracts for chromatographic separation were obtained from a carbon black filled NBR vulcanisate. Possible errors in the preparation of the extracts are discussed. Gas chromatography does not show a number of ingredients due to their low volatility and to thermal decomposition in the injection port or on the column. HPLC conceals substances with low UV absorption. Substances early eluted in HPLC show peak broadening from strong extraction solvents; with dithiocarbamates, interaction with heavy metals from metallic parts of the equipment were noted. The influence of pH of the eluent is demonstrated; with its variation and with changes in the detection wavelength an optimisation in HPLC separation power can be achieved. 14 refs.

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References and Abstracts

EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.721414 Item 161 Journal of Applied Polymer Science 71, No.12, 21st March 1999, p.1995-2005 ANALYSIS OF UNBOUND MATERIALS IN CARBON-BLACK-FILLED NR VULCANIZATES Sung-Seen Choi; Hoon Kim; Jong In Kim; Haeng Rok Cho; Dong Kyu Oh Kumho R & D Center The extraction of unbound materials from carbon blackfilled NR vulcanisates with different cure systems was studied using various solvents with different dielectric constants (n-hexane, toluene, THF, acetone and acetonitrile). The extraction was performed at room temp. and 40C for 2 days and in the boiling solvent for 8 h. Amounts of materials extracted from the NR vulcanisates with n-hexane, toluene and THF were greater than those with acetone and acetonitrile. Amounts of extracted materials from the NR vulcanisate with a high crosslink density were less than those from the NR vulcanisate with a low one. TGA of the NR vulcanisates before and after the extraction were carried out to investigate components of the extracted materials. It was found that there were polymer components and metal complexes, as well as organic materials with a low molec.wt., in the extracted materials. Abilities of the solvents to extract unbound materials from the NR vulcanisates are discussed. 13 refs. KOREA

Accession no.719466 Item 162 Journal of Applied Polymer Science 71, No.12, 21st March 1999, p.1987-93 MIGRATION BEHAVIORS OF ANTIOZONANTS TO THE SURFACE IN NR VULCANIZATES, DEPENDING ON THE SEASON: EFFECT OF WAX Sung-Seen Choi Kumho R & D Center The effect of a wax film on the surface of a rubber vulcanisate on migration of antiozonants was studied outdoors for two months in the summer, autumn and winter using NR vulcanisates containing various types of waxes with different MWDs. The antiozonants used were N-phenyl-N’-isopropyl-p-phenylenediamine(IPPD), N-phenyl-N’-(1,3-dimethylbutyl)-pphenylenediamine(HPPD), N,N’-di(sec-butyl)-pphenylenediamine(SBPPD) and N,N’-di(1,4dimethylpentyl)-p-phenylenediamine(DMPPD). The migration rates of the antiozonants in the vulcanisate without wax were faster than those in the vulcanisates with waxes. The antiozonants migrated slower in the vulcanisate containing wax with a higher MWD than in

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the vulcanisate with a low one. In summer, the migration rates of SBPPD and DMPPD were faster than those of IPPD and HPPD, respectively. In the autumn, however, the migration rates of SBPPD and DMPPD were slower than those of IPPD and HPPD, respectively. The differences of migration behaviours of the antiozonants, depending on season and wax type, are discussed. 12 refs. KOREA

Accession no.719465 Item 163 ACS Polymeric Materials Science & Engineering, Spring Meeting 1998. Volume 78. Conference proceedings. Dallas, Tx., Spring 1998, p.61. 012 CHARACTERISATION OF HYDROXYLTERMINATED POLYBUTADIENES USING TWO-DIMENSIONAL CHROMATOGRAPHY Pulda J Kaucuk AS (ACS,Div.of Polymeric Materials Science & Engng.) Hydroxyl-terminated polybutadienes (HTPB) are low molecular weight prepolymers with considerable importance in many applications. Their specific properties are utilised in the formulation of special oil or PU coatings, adhesives, scaling materials, binders for solid propellants and other products. Mechanical properties and ageing characteristics of these products are correlated particularly with distributions of molecular weights and functionality of polybutadiene. For example, in spite of the fact that only bifunctional molecules are expected, non- and monofunctional species are also generated in the case of anionic polymerisation. Therefore, the determination of these independent distributions is very important for prediction of mechanical properties of the products. Emphasis is placed on the simultaneous determinations of the molecular weight distribution and functionality type distribution of HTPB (with a dominant content of 1,2units; prepared by anionic polymerisation) and verification of separated fractions according to their functionality. 7 refs. CZECH REPUBLIC

Accession no.719171 Item 164 ACS Polymeric Materials Science & Engineering, Spring Meeting 1998. Volume 78. Conference proceedings. Dallas, Tx., Spring 1998, p.25-6. 012 SURFACE IMAGING AND DEPTH PROFILING OF LATEXES: SS-PAS AND ATR FT-IR/FTRAMAN MICROSCOPY Zhao Y; Urban M W North Dakota State University (ACS,Div.of Polymeric Materials Science & Engng.)

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It has been indicated that the mobility of low molecular weight materials, in particular surfactant molecules, may be affected by the glass transition temperature and subsequently, by free volume of a polymer matrix, surface tension at the film-air and film/substrate interfaces, compatibility and coalescence times, to name just a few. The scope of previous studies is expanded, utilising attenuated total reflectance, FT-Raman microscopy and step-scan photoacoustic Fourier transform infrared spectroscopy in an attempt to elucidate a molecular origin of latex non-homogeneity. 8 refs. USA

Accession no.719143 Item 165 ACS Polymeric Materials Science & Engineering, Spring Meeting 1998. Volume 78. Conference proceedings. Dallas, Tx., Spring 1998, p.132. 012 ANALYSIS OF CHAIN DYNAMICS AND SHORTRANGE ORDER IN BLOCKY COPOLYMERS BY SOLID STATE NMR White J L; Dias A J Exxon Chemical Co. (ACS,Div.of Polymeric Materials Science & Engng.) Polyisobutylene is unique among elastomeric polymers in that while the glass transition temperature is low, segmental dynamics at temperatures above Tg are relatively slow due to steric constraints resulting from the molecular packing of methyl groups. Results of NMR experiments on solid polyisobutylene (PIB) and copolymers with paramethylstyrene (PIB-PMS) are described in which the dynamics of chain motion in PIB homopolymers and PIBPMS copolymers are compared as function of temperature. One- and two-dimensional solid-state 1H, 13C and 2H results clarify previously published reports on local vs. correlated segmental dynamics for PIB. Distinct differences in aromatic ring dynamics as a function of PMS concentration are also observed for PIB-PMS copolymers. While PMS dynamics are found to be sensitive to PMS concentration in the copolymer, PIB motions appear to be independent of the comonomer incorporation. These results may be understood based on the clustered or blocky incorporation of PMS comonomer segments in the polymer chain. Relaxation and 2D HETCOR experiments are used to define morphology for the PMS clusters in the copolymer, and the results are consistent with a 3 nm domain size for the clusters. Emphasis is placed on the morphological information available from the 2D 13C-1H HETCOR/spin diffusion technique. 5 refs. USA

Accession no.719070 Item 166 ACS Polymeric Materials Science & Engineering, Spring Meeting 1998. Volume 78. Conference proceedings.

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Dallas, Tx., Spring 1998, p.111-2. 012 SMALL ANGLE NEUTRON SCATTERING FROM ISOTOPIC AND DIBLOCK COPOLYMER STAR MOLECULES Hutchings L R; Richards R W; Thompson R L Durham,University (ACS,Div.of Polymeric Materials Science & Engng.) Star polymers where all the arms are of equal length constitute the simplest branched polymer architecture because all the grafts emanate from a single point. Polymers of this type provide models to explore the rheological and structural aspects of branched polymers and these studies are relevant to the most recent forms of star type polymers, dendrimers. When the star polymer may itself be a copolymer of some sort, then the combination of isotopic, chemical and architectural differences when the star polymer is mixed with linear polymers may lead to distinctive behaviour in the interaction parameters as the composition of the linear/ star polymer blend is altered. The simplest system in terms of small angle neutron scattering is a star polymer where only one arm of the star is deuterium labelled. This type of molecule is also interesting because in principle it allows us to evaluate the radius of gyration of the labelled arm directly and thus determine the effect of grafting density. Furthermore such molecules allow the possibility to be addressed that parameter between labelled and unlabelled arms may differ from that between linear (matrix) polymer and the labelled arm. The results of small angle neutron scattering (SANS) experiments on star polymers of polybutadiene, wherein one arm is full deuterium labelled, are discussed. Star polymers have been mixed with linear hydrogenous polymer with molecular weight equal to that of the arm and equal to that of the star polymer. The scattering laws are outlined and details of the experiments are presented. Selected results epitomise the data and some of the results of fitting the scattering laws to the data are given. 10 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.719058 Item 167 Kautchuk und Gummi Kunststoffe 51, No.12, Dec.1998, p.865-7 DETECTION OF INTERFACIAL LAYERS IN ELASTOMER SAMPLES BY NMR IMAGING Blumler P; Litvinov V; Dikland H G; van Duin M Aachen,RWTH; DSM Research BV The detection of interfacial layers in EPDM samples by NMR imaging is reported. Although the samples were prepared on laboratory scale equipment, it is very likely that similar structures will be caused by folding and pressing processes in typical rubber mixing methods. Spin-echo and gradient-echo techniques were used to differentiate between voids and inhomogeneities inside the elastomer by characteristic changes of the magnetic susceptibility. Layer-

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References and Abstracts

like structures were observed which result from folding of the material during the mixing process. Although these layers are glued together by the flow and tack of the material, the interface remains different from the bulk. A healing of the interface is possibly slowed down because of the high entanglement density in EPDM. The existence of such interfacial layers may have significance for other analytical methods which probe bulk properties as well as for failure analysis. 9 refs.

The microstructure of rubber blends of nitrile rubber, styrene-butadiene rubber and chloroprene rubber was studied using light microscopy, scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. The atomic force microscopy was found to be the best method for studying the morphology of low-compatibility rubber blends. 3 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology.

EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; NETHERLANDS; WESTERN EUROPE

EASTERN EUROPE; HUNGARY

Accession no.718676

Accession no.716736

Item 168 Macromolecular Chemistry & Physics 200, No.2, Feb.1999, p.358-67 PHOTOCROSSLINKING OF FUNCTIONALISED RUBBERS. VII. SBR BLOCK COPOLYMERS Decker C; Viet T N T CNRS

Item 171 Gummi Fasern Kunststoffe 51, No.9, Sept.1998, p.729-33 German CHARACTERISATION OF THE DISTRIBUTION OF MINERAL OIL PLASTICISER COMPONENTS IN ELASTOMER BLENDS Giese U; Peterseim V; Schuster R H DIK

The photocrosslinking of SBR was monitored using IR spectroscopy. The disappearance of the pendent vinyl double bonds upon UV exposure in the presence of an acylphosphine oxide photoinitiator was monitored. 29 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.716966 Item 169 Nippon Gomu Kyokaishi 71, No.9, 1998, p.541-8 Japanese ANALYSIS OF THE INTERACTION BETWEEN POLYMER AND FILLER - CARBON BLACK Nishi T Tokyo,University The author discusses the interface between polymers and other materials, and reviews the analysis of interaction between polymers (using natural rubber) and carbon black using pulse nuclear magnetic resonance and other methods. 30 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.716741 Item 170 Muanyag es Gumi 35, No.7, July 1998, p. 209-14 Hungarian INVESTIGATING THE MORPHOLOGY OF LESS COMPATIBLE RUBBER BLENDS Nagy P; Czvikovsky T; Nagy T T; Seregely I; Nagy P Budapest,Technical University; Taurus Emerge Gumiipari Kft; MTA Central Chemical Research Institute

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The authors discuss how the processability of rubber mixes and the mechanical properties of vulcanisates are controlled and influenced by the addition of plasticisers such as those based on mineral oils. Especially in binary rubber blends, the effect of the plasticiser is determined by the equilibrium distribution of the plasticiser or individual plasticiser components between the elastomer phases. A method has been developed for monitoring this equilibrium distribution, based on a diffusion test in a sandwich arrangement followed by determination of plasticiser concentrations in the separate polymer phases by extraction using high-pressure liquid chromatography. 23 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.716715 Item 172 Kauchuk i Rezina (USSR) No.3, 1998, p.35-8 Russian PREPARATION OF ELASTOMER COMPOSITIONS BY ACTIVATING MIXING Britov V P; Rebnitskii A V; Sevast’yanov L K; Bogdanov V V St.Petersburg,Technological Institute The authors discuss the theory of “activating mixing”, when the energy transmitted to mix components is expended not only on dispersion and homogenisation but also on the initiation of chemical interactions between the components. The infrared spectra and physicomechanical properties of various blends of rubbers are

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sample mixing methods. The results obtained are discussed from the viewpoint of the supersaturation theory. 12 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology.

shown, and the possibility is established of using activating mixing in processes for obtaining epoxy-rubber compositions and for the modification of polyisoprene in solution. 8 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology.

JAPAN

RUSSIA

Accession no.713851

Accession no.716686 Item 173 Journal of Rubber Research 1, No.4, 1998, p.199-208 EPOXIDE GROUPS IN NR. II. CARBON 13 NMR STUDY OF UNDEGRADED NR Eng A H; Kodama S; Tangpakdee J; Kawahara S; Tanaka A Y Malaysia,Rubber Research Institute; Okayama Prefecture Industrial Technology Centre; Tokyo,University of Agriculture & Technology The level of epoxide groups on the NR main chain molecule was examined using carbon 13 NMR. 9 refs. JAPAN; MALAYSIA

Accession no.716199 Item 174 Nippon Gomu Kyokaishi 71, No.3, 1998, p.129-39 Japanese STRUCTURAL CHARACTERISATION OF ELASTOMERS BY X-RAY SCATTERING METHODS Murakami T; Murakami S; Ikeda Y Kyoto,University A survey and description of techniques of analysis of elastomers using X-ray scattering, including the imaging plate and position sensitive proportional counter, are given. 39 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.713941 Item 175 Nippon Gomu Kyokaishi 71, No.1, 1998, p.54-60 Japanese EFFECTS OF SOME FACTORS RELATED TO THE SUPERSATURATION THEORY ON THE BLOOMING OF ALIPHATIC AMIDES Mori K; Shimizu K; Okoshi M; Matsunami S Iwate,University; Nippon Kasei Co.Ltd. Blooming of aliphatic amides from NBR vulcanisates was investigated with regard to the effect of stearamide concentration, the types of aliphatic amides used, methods of testing and monitoring the blooming, and different

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Item 176 Nippon Gomu Kyokaishi 71, No.2, 1998, p.90-7 Japanese ANALYSIS OF STATE OF DISPERSION OF COMPOUNDED RUBBERS BY TRANSMISSION ELECTRON MICROSCOPY Maehara A; Akiyama S Bridgestone A review is presented of modern technologies used for rubber analysis (analytical electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, electron energy loss spectroscopy), and the use of transmission electroscopy for analysis of the dispersion of NR/SBR and NR/BR blends is described. 13 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.713795 Item 177 Nippon Gomu Kyokaishi 71, No.2, 1998, p.78-84 Japanese STRUCTURAL ANALYSIS OF VULCANISED RUBBER BY PYROLYSIS-GAS CHROMATOGRAPHY Okumoto T Toyoda,Technical University Analysis of the structure of vulcanised elastomers such as EPDM by pyrolysis-gas chromatography is described. 15 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.713793 Item 178 Nippon Gomu Kyokaishi 71, No.2, 1998, p.68-77 Japanese HIGH-RESOLUTION NMR STUDIES OF VULCANISED ELASTOMERS Mori M; Koenig J L Yokohama Rubber Co.; Case Western Reserve University

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References and Abstracts

A review is given of the application of high-resolution nuclear magnetic resonance for analysis composition and cure of vulcanised elastomers. 68 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.713792 Item 179 ACS Polymeric Materials Science and Engineering. Fall Meeting 1998. Volume 79. Conference proceedings. Boston, Mas., 23rd-27th Aug.1998, p.352-3. 012 SMALL-ANGLE X-RAY SCATTERING AND DSC STUDIES ON THE DOMAIN STRUCTURE AND INTERPHASE DIMENSIONS IN POLYURETHANE-UREA Musselman S G; Santosusso T M; Sperling L H Air Products & Chemicals Inc.; Lehigh University PU elastomers are phase-separated multiblock copolymers composed of a glassy or crystalline hard block and an elastomeric soft block. Polyether or polyester diols ranging in molecular weights from 500 to 5000 g/mol comprise the soft segments, while diisocyanates composed of the reaction products of chain extenders or crosslinkers comprise the hard segments. When diamines are used as the chain extender, the resultant polymers are known as polyurethane-ureas. These materials can undergo crosslinking through the formation of allophonate or biuret bonds. Physical crosslinking is also present in these materials as a consequence of hydrogen bonding and crystallinity. The elastomers of this study utilise TDIterminated polytetramethylene glycol prepolymers with chains extended with the diamines 4,4'-methylene bis-2chloroaniline (MBOCA) or 4,4'-methylene bis-(3-chloro2-6-diethylaniline) (MCDEA) as chain extenders. The use of these chain extenders has been shown to result in improvements in physical and mechanical behaviour of these PU elastomers. Prepolymers containing a broad distribution of oligomers and those with controlled oligomer content are compared to determine if differences in tensile, compression and thermal properties are the result of differences in morphology as determined by SAXS and differential scanning calorimetry. The objective is to evaluate the microstructure of this new class of materials and to examine whether these parameters correlate with end use behaviour. USA

Accession no.713425 Item 180 Kauchuk i Rezina (USSR) No.5, 1997, p.15-6 Russian COMPARATIVE ASSESSMENT OF THE EFFECTIVENESS OF ETHYLENE-PROPYLENE

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RUBBER STABILISERS UNDER CONDITIONS OF THERMOMECHANICAL DEGRADATION Kimel’nlat V I; Vol’fson S I; Chebotareva I G; Kadyrova V K; Mukmeneva N A Kazan,State Technological University The authors describe the use of pressure relaxation time spectra of ethylene-propylene rubber for the assessment of changes in the molecular structure of the polymer. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. RUSSIA

Accession no.713247 Item ß181 Kauchuk i Rezina (USSR) No.1, 1997, p.16-20 Russian INFLUENCE OF THE MICROSTRUCTURE OF POLYBUTADIENES ON THE FORMATION OF NETWORK STRUCTURES IN THEIR BLENDS WITH CIS-1,4-POLYISOPRENE Shershnev V A; Shundrina I K; Yulovskaya V D; Evreinov Yu V Moscow,Lomonosov Institute The materials studied were mixtures of cis-1,4polyisoprene and polybutadienes differing in their content of 1,4- and 1,2-units.The influence of the microstructure on the formation of network structures was studied by investigating the glass transition temperature, relaxation component of deformation and the mechanical properties of the vulcanisates. 8 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. RUSSIA

Accession no.711979 Item 182 Macromolecules 31, No.25, 15th Dec.1998, p.8871-7 ROUSE AND REPTATION DYNAMICS OF LINEAR POLYBUTADIENE CHAINS STUDIED BY DEUTERIUM NMR TRANSVERSE RELAXATION Klein P G; Adams C H; Brereton M G; Ries M E; Nicholson T M; Hutchings L R; Richards R W Leeds,University; Durham,University Deuterium NMR was used to investigate two different types of dynamics of linear polybutadiene chains in the melt. The transverse relaxations of short Rouse chains of molecular weight 640-3000 were biexponential, which has been attributed to separate decays of the methylene and methine deuterons. Interpretation of the transverse relaxation rates using a model for Rouse dynamics, combined with molecular simulations, gave the shortest

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Rouse unit as approximately 4.4 monomers and the shortest Rouse time as 0.00000083 s. The reptation dynamics of higher molecular weight entangled chains were investigated using ABA isotopic triblock copolymers, of total molecular weight 14000-135000, where A is protonated polybutadiene of molecular weight greater than the entanglement molecular weight and B is a deuterated block. These polymers were specifically synthesised so that the fast motion of the Rouse-like chain ends should not complicate the signal. The fundamental parameters found for the Rouse chain were used in the reptation model, assuming fast dynamics, and gave an entanglement molecular weight, of 5380 or approximately 21 Rouse units. This entanglement molecular weight is more than twice the conventional value, obtained from rheology, and is more suggestive of the critical molecular weight, consistent with previous NMR work. The theoretical analysis used in this work is based on the assumption that the chain dynamics are fast on the time scale set by the NMR deuterium quadrupolar interaction. The highest molecular weight samples were found to not satisfy this criterion and indicate the molecular weight at which a new theoretical approach is needed. 19 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.711635 Item 183 Angewandte Makromolekulare Chemie Vol.261/262, Dec.1998, p.123-33 USE OF NMR RELAXATION AND NMR IMAGING IN STUDYING THE AGEING OF RUBBER Knorgen M; Heuert U; Menge H; Schneider H Halle,Martin-Luther-Universitat NMR was used to study the ageing of rubber filler materials. The methods used are spin-echo hydrogen ion NMR including variable echo times and parameterselective NMR hydrogen ion imaging (materials properties imaging). The decay of the echo-magnetisation is discussed on the basis of a single chain model with a distribution of dipolar interactions. This model is based on the influence of a very fast but anisotropic local motion as well as larger and slower motions, which are liable to diminish the residual dipolar interaction. Carbon black filled NR as well as silica and carbon black filled emulsion- and solution-SBR and milled tyre rubber are the systems under investigation showing some characteristic features of the ageing course observable by NMR. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.711102 Item 184 Angewandte Makromolekulare Chemie Vol.261/262, Dec.1998, p.1-7

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IMAGING CHEMILUMINESCENCE TECHNIQUE APPLIED TO THERMOOXIDATION OF POLYMERS POSSIBILITIES AND LIMITATIONS Ahlblad G; Reitberger T; Terselius B; Stenberg B Sweden,Royal Institute of Technology; Kristianstadt,University Advances in imaging chemiluminescence were briefly summarised and recent results obtained by monitoring the oxidation depth profiles in polybutadiene rubber and the physical spreading of oxidation between EPDM particles were presented. The potential and the limitations of the technique were discussed in some detail. 23 refs. SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.711090 Item 185 IRC ’98. Conference Proceedings. Paris, 12th-14th May 1998, p.357-8. 012 French AFM STUDY OF SILICA DISPERSION IN FILLED ELASTOMERS UNDER DEFORMATION Lapra A; Bokobza L; Monnerie L; Silberzan P ESPCI (AFICEP; Societe de Chimie Industrielle) Results are presented of tapping mode atomic force microscopy studies of filler dispersion in stretched and unstretched samples of silica filled SBR. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.710629 Item 186 IRC ’98. Conference Proceedings. Paris, 12th-14th May 1998, p.283-8. 012 French RUBBER AND ATMOSPHERIC EMISSIONS: REGULATIONS AND ANALYTICAL TECHNIQUES Aubin C; Coupard A; Khalfoune H; Le Huy M LRCCP; SEP-DPPC (AFICEP; Societe de Chimie Industrielle) French and European Union legislation relating to the control of emissions in the workplace is examined, with particular reference to the rubber processing industry. Air sampling and analytical procedures used in the detection of nitrosamines formed in vulcanisation reactions are reviewed. 2 refs. EU; EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE; WESTERN EUROPE-GENERAL

Accession no.710622 Item 187 IRC ’98. Conference Proceedings.

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References and Abstracts

Paris, 12th-14th May 1998, p.259-60. 012 French STUDY OF THE INFLUENCE OF VULCANISATION ON N-NITROSAMINE FORMATION MECHANISMS IN RUBBERS Amelot V; Derouet D; Brosse J C; Aubin C; Gomez E Maine,Universite; LRCCP; IFOCA (AFICEP; Societe de Chimie Industrielle) The methodology used in a study of nitrosamine formation in vulcanisation processes accelerated by tetraethylthiuram disulphide is described. This involved the characterisation of nitrosable species and the mechanisms of their formation, and studies of the influence of vulcanisation reactions and curing systems on the formation of nitrosable species. The results of the study are summarised. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.710619 Item 188 IRC ’98. Conference Proceedings. Paris, 12th-14th May 1998, p.237-8. 012 French MODELLING THE VULCANISATION OF THICK COMPONENTS Boube M F Hutchinson SA (AFICEP; Societe de Chimie Industrielle) The vulcanisation kinetics of thick diene rubber components were characterised by rheometric and DTA techniques, and the results were compared in experimental studies and finite element analysis. Predictions obtained on the basis of DTA measurements were found to be unreliable, and more precise simulations were obtained using a vulcanisation model based on rheometric measurements. 3 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.710616 Item 189 Nippon Gomu Kyokaishi 70, No.5, 1997, p.269-73 Japanese SUITABILITY OF THE TWO THEORIES OF BLOOMING OF STEARAMIDE FROM NBR Mori K; Shimizu K; Matsunami S Iwate,University; Nippon Kasei Co.Ltd. Blooming of stearamide (SA) in NBR vulcanisates was studied with regard to factors such as bloom weight, nitrile content of the NBR, solubility of SA in NBR, relation between the solubility parameters of NBR and SA, and DSC measurement of SA in NBR. The bloom weight decreased with increase in acrylonitrile content from 0 to almost 29%, and the solubility of the SA in NBR also

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increased. In NBR with acrylonitrile content exceeding 29%, the bloom weight decreased gradually, though the solubility decreased. Similar results were obtained in the relation between bloom weight and difference in solubility parameters of SA and NBR. This shows that either of the two blooming mechanisms is operating in the blooming of SA in MBR. In NBR with low acrylonitrile content the supersaturation mechanism explains the blooming of SA, and in NBR with high acrylonitrile content the energy slope mechanism may be applied for the blooming of SA. 8 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.710483 Item 190 Nippon Gomu Kyokaishi 70, No.6, 1997, p.325-32 Japanese PLASMA TREATMENT OF ELASTOMERS Naito K; Kato N Bridgestone Co.Ltd. The method and equipment for low-temperature plasma treatment of elastomers are described, and spectroscopic and microscopic methods for analysis of the treated surfaces are reviewed. 69 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.710433 Item 191 Materiale Plastice 34, Nos.3-4, 1997, p.203-9 Rumanian SPECTRAL CHARACTERISATION OF POLYDIENES OBTAINED WITH THE NDCL3 3TBP-TIBA CATALYTIC SYSTEM Iovu H; Hubca G; Dimonie M; Simonescu E; Badea E G Bucharest,Polytechnic University; ICECHIM Polyisoprene and polybutadiene obtained with the NdCl3 3TBP-TIBA catalytic system in different conditions, were characterised by their IR, H-NMR, C-NMR and Raman spectra. The microstructure of the respective polymers was evaluated quantitatively from the IR spectra and only qualitatively from the rest of the spectra. Both polymers have a high 1,4-cis unit content. 13 refs. EASTERN EUROPE; RUMANIA

Accession no.709984 Item 192 Journal of Adhesion Science and Technology 12, No.12, 1998, p.1377-90

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SURFACE STUDIES ON THE ADDITIVE MIGRATION AND DIFFUSION IN THE WINDOWSEAL RUBBER COMPONENT INFLUENCING ADHESION TO COATING Dimopoulos M; Choudhury N R; Ginic-Markovic M; Matisons J; Williams D R G South Australia,University; Adelaide,University The diffusion behaviour of additives of different rubber samples (masterbatch and final automotive EPDM rubber compounds) was identified and quantified using complementary techniques such as contact angle measurements, X-ray photoelectron spectroscopy(XPS), size exclusion chromatography and ATR FTIR spectroscopy. The influence of different methods of processing (milling and extrusion) on the diffusion behaviour and change in rubber surface chemistry was investigated. Contact angle measurements using scanning Wilhelmy and sessile drop methods over prolonged time mainly showed an increase in the polar component of the surface energy for the samples, although the total surface energy did not change significantly. XPS analysis showed that, in masterbatch samples, the main additive excluded on the surface was the zinc salt of fatty acid. The diffusion coefficient of zinc stearate was found to be 0.0000001083 sq cm/s from contact angle measurement, which was in good agreement with other stearate diffusants in the rubber matrix. Sulphur diffusion over time was more marked in the milled final sample. SEC indicated a mixture of additives with different molec.wts. extracted from the sample surface. 15 refs. AUSTRALIA

Accession no.709678 Item 193 Composite Interfaces 6, No.1, 1999, p.19-25 TRIMETHYLCHLOROSILANE MODIFIED SILICA SURFACES: CHARACTERIZATION BY INVERSE GAS CHROMATOGRAPHY(IGC) USING POLYDIMETHYLSILOXANE(PDMS) OLIGOMERS AS PROBES Balard H; Papirer E; Khalfi A; Barthel H Institut de Chimie des Surfaces et Interfaces; Wacker Chemie GmbH The use of IGC, with PDMS oligomers as specific molecular probes, to monitor the influence of the trimethylsiloxy group coverage on the surface properties of silylated silica in a large range of silylation ratios is discussed. The use of IPC to provide the value of the PDMS monomer unit/silica surface interaction energy is also described. 5 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; GERMANY; WESTERN EUROPE

Accession no.709621

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Item 194 Second International Conference on Carbon Black. Conference proceedings. Mulhouse, 27th-30th Sept.1993, p.119-22. 51B SIMS/XPS INVESTIGATIONS ON THE SURFACE CHEMISTRY OF RUBBER AND COLOUR BLACKS Albers P; Freund B; Prescher G; Seibold K; Wolff S Degussa AG (Societe Francaise de Chimie; CNRS; HauteAlsace,Universite; Societe Industrielle de Mulhouse; Ecole Nationale Superieure de Chimie de Mulhouse) There are numerous parameters that govern the reinforcing potential of rubber blacks. These are specific surface area, aggregate size and shape distributions (structure) and surface activity. Hydrogen content particularly plays an important role in the reinforcing potential, because it can affect the surface activity. A partial graphitisation of rubber blacks leads to a decrease in the reinforcing properties, partially due to a reduced concentration of hydrogen on the surface. This reduction in hydrogen can be measured by tracer techniques or SIMS. Variations in hydrogen content are surface related properties of carbon blacks, and correlate directly to the tread wear rating. It is possible to qualitatively discriminate between enhanced aliphatic and aromatic/ graphitic surface hydrogen. These investigations focus on the suitability of using SIMS measurements at different erosion rates or sputter times as a means to detect surfacebonded hydrogen as well as its concentration profile in regions adjacent to the surface. Furthermore, by taking advantage of the different fragmentation characteristics of carbon blacks, it is possible to use controlled ioninduced decomposition as a method to measure the different sensitivities of carbon black surfaces. 6 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.709093 Item 195 Slovak Rubber Conference ’97. Conference proceedings. Puchov, 20th-21st May 1996, p.350-65. 4 RUBBER PROPERTIES AS A FUNCTION OF CARBON BLACK SURFACE AREA AND AGGREGATE SIZE Columbian Chemicals Co. (Matador AS) It is well known that SBR, BR, NBR, EPDM and other elastomers in which the molecular chains are not oriented when stretched yield low gum tensile strength (300-400 psi). The same polymers, when compounded with 50 phr of selected carbon black may yield a vulcanised tensile strength as high as 4000 psi. This improvement in breaking strength is identified as a reinforcement effect. Increasing reinforcement has been defined as increased modulus, rupture energy, tear and tensile strength,

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References and Abstracts

cracking, fatigue and abrasion resistance. Today, rubber compounders can select from a wide range of commercial carbon blacks depending on the properties imparted to the final rubber product, as well as compound processability and cost. Some of the different aspects of carbon black reinforcement are reviewed, emphasising the effects of varied carbon black colloidal properties and black loading on the processing and vulcanisate properties for different elastomers. 20 refs. USA

Accession no.708413 Item 196 Slovak Rubber Conference ’97. Conference proceedings. Puchov, 20th-21st May 1996, p.179-88. 4 Slovak KINETIC ANALYSIS OF VULCANISATION IN RUBBER COMPOUNDS BY DSC Simon P; Taraba V; Kucma A Bratislava,Slovak Technical University; Matador AS (Matador AS) The kinetic analysis of curing of rubber compounds, measured by DSC, is presented. A new method of obtaining the kinetic parameters, of induction period of vulcanisation from non-isothermic DSC measurements, is proposed. The difference between the induction periods measured by DSC and a rheometer is explained by a difference in the mechanism of heat transfer in both methods. It is shown that the model of n-th order reaction describes the kinetics of vulcanisation very satisfactorily when the existence of induction period is taken into account. The possible use of the dynamic DSC method in the study of rubber compounds curing is proposed. 9 refs. SLOVAK REPUBLIC; SLOVAKIA

Accession no.708394 Item 197 Polymer Degradation and Stability 63, No.1, 1999, p.121-6 CROSSLINKING ON AGEING OF ELASTOMERS. I. PHOTOAGEING OF EPDM MONITORED BY GEL, SWELLING AND DSC MEASUREMENTS Baba M; Gardette J L; Lacoste J Blaise Pascal,Universite The crosslinking reactions occurring during the photooxidation of EPDM (Vistalon 7500) were examined by measuring changes in gel fraction, degree of swelling and freezing point by DSC. The correlation with the variation of the carbonyl index showed that the crosslinking process was very efficient (similar to that obtained by peroxide vulcanisation) and occurred at the very early stages of the photooxidation. Gel fraction measurements showed that chain scissions were detected as soon as the

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formation of oxidation photoproducts could be observed by IR analysis of the oxidised polymer. 19 refs. EXXON EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.708140 Item 198 Polymer Degradation and Stability 62, No.2, 1998, p.395-401 OXIDATION OF RUBBERS ANALYSED BY HORIZONTAL ATR/IR SPECTROSCOPY Delor F; Barrois-Oudin N; Duteurtre X; Cardinet C; Lemaire J; Lacoste J Blaise Pascal,Universite; Renault; Hutchinson The analysis of rubbers containing large amounts of carbon black by IR spectroscopy is difficult, particularly studies of their chemical evolution upon ageing. The use of a horizontal ATR accessory equipped with a germanium crystal is described. Horizontal ATR(Ge)/FTIR analysis of both thermal- and photooxidations of EPDM, polychloroprene and NBR were first validated by conventional transmission spectroscopy in the absence of carbon black. Horizontal ATR(Ge) was then used with fully formulated rubbers with the aim of studying their long-term behaviour. The effects of temp., UV exposure, carbon black or stress as well as the oxidation profile across the materials on the identification of carboxylic acid/carboxylate groups were examined. 8 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.706569 Item 199 Polymer Science Series B 40, Nos.9-10, Sept.-Oct.1998, p.357-64 THERMOMECHANICAL ANALYSIS FOR DETERMINATION OF THE MOLECULAR MASS DISTRIBUTION OF BULK POLYMERS Ol’khov Y A; Irzhak V I Russian Academy of Sciences Methodological aspects of using the thermomechanical analysis technique for the determination of the MWD of linear polymers and tie chains of crosslinked polymers in the bulk are considered. The possibilities offered by this method and the applicability limits of the approach are demonstrated. 20 refs. (Full translation of Vys.Soed.B, 40, No.10, 1998, p.1706-14) RUSSIA

Accession no.706449 Item 200 IRC ’98. Conference proceedings. Paris, 12th-14th May 1998, p.115-6. 012 STATE OF CURE MEASUREMENTS ON THIN REINFORCED ELASTOMERS BY AN ULTRASONIC TECHNIQUE

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Kirchhoff J; Knoop F-M; Mewes D Hannover,Universitat; ContiTech Holding GmbH (AFICEP; Societe de Chimie Industrielle) An ultrasonic technique is used to examine the state of cure, or the effect of heating time, respectively, in thin calendered sheets of elastomers. Sample thicknesses are 2 and 1 mm. The samples are partially reinforced by a fabric layer. Results of the measurements are presented for NBR and NR type carbon black-filled elastomers. An ultrasonic transmission technique is used for the experiments. The frequency of the ultrasonic pulse is in the range of 2 MHz. By measuring speed of sound and attenuation of the elastomers, the state of cure can be characterised. The temperature effect on ultrasonic measurements in NBR and NR type elastomers is described. 4 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.706204 Item 201 IRC ’98. Conference proceedings. Paris, 12th-14th May 1998, p.113-4. 012 SYNTHESIS AND USE OF DEUTERATED POLYBUTADIENE TO STUDY FILLER/CARBON BLACK INTERACTIONS BY SOLID STATE NMR Joguet L; Haidar B; Vidal A; Delmotte L ICSI-CNRS; Ecole National Superieur de Chimie de Mulhouse (AFICEP; Societe de Chimie Industrielle) Solid-state NMR is an established method to study the mobility of macromolecular chains through numerous possible approaches. An appropriate spectroscopic method for the study of glassy or extremely low mobility states is 2H NMR. It provides, under some assumptions, an access to lower correlation times of motions than 1H or 13C NMR techniques. Partially deuterated polybutadiene is synthesised by anionic polymerisation, with different molecular weights ranging from 2,000 to 70,000 g/mol, and an identical microstructure. The results of solid-state NMR investigation are reported. 4 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.706203 Item 202 IRC ’98. Conference proceedings. Paris, 12th-14th May 1998, p.105-6. 012 INVERSE GAS CHROMATOGRAPHY: INVESTIGATION OF SILICAS USED FOR THE REINFORCEMENT OF PDMS ELASTOMERS Papirer E; Balard H; Khalfi H; Barthel H ICSI-CNRS; Wacker Chemie GmbH (AFICEP; Societe de Chimie Industrielle) Important characteristics of fillers for elastomers are particle size and size distribution, particle morphology

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and extent of surface area, as well as surface properties such as surface groups nature and content and surface energy. The determination of particle size and other bulk properties may be made using standard methods. Evaluation of surface chemical characteristics is far from a solved problem. These latter define, on one hand, the chemical surface reactivity, but also the aptitude of the surface to undergo surface modification procedures that are currently performed to adapt the surface characteristics for optimum dispersion or interaction with the polymer matrix. Given the specificity of the surface groups, there is no universal method for the modification of fillers. In fact, there are methods designed for each family of fillers. This is typically the case for silicas used for the reinforcement of polydimethylsiloxane (PDMS). The use of inverse gas chromatography to investigate the surface properties of silica-filled PDMS is described. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; GERMANY; WESTERN EUROPE

Accession no.706201 Item 203 IRC ’98. Conference proceedings. Paris, 12th-14th May 1998, p.87-8. 012 XPS AND XRD STUDY OF PHENOMENA AT RUBBER-STEEL CORD INTERFACE UNDER DIFFERENT AGEING CONDITIONS Dujko E; Cerelast S C Bucharest,Research Institute for Rubber Processing (AFICEP; Societe de Chimie Industrielle) It has been shown that chemical and crystallographic structure of rubber-brass plated cord interface is critical for adhesion strength. The analysis of the compounds formed at interface during vulcanisation and of the structure modification during post-vulcanisation under degradation conditions could offer interesting and useful information about the rubber compounds and cord parameters. Surface and interface analytical techniques are developed for the study of composite structure of rubber-cord layer and to establish possible correlations between certain diffusion phenomena to interface of the adhesion bonds-determining elements, adhesion strength, bonding resistance under degradation conditions. Two rubber compounds typically for bonding to brass-plated cord are studied with different adhesive systems. EASTERN EUROPE; RUMANIA

Accession no.706197 Item 204 IRC ’98. Conference proceedings. Paris, 12th-14th May 1998, p.407. 012 AN EVALUATION OF CROSSLINKING REACTIONS OCCURRING IN PHOTO AND THERMAL OXIDATION OF DIENIC ELASTOMERS Baba M; Commereuc S; Lacoste J

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References and Abstracts

UMR CNRS (AFICEP; Societe de Chimie Industrielle) When subjected to oxidation, dienic elastomers are altered both in their chemical structures and in their mechanical characteristics. Among these alterations the appearance of oxidation products (with or without chain scissions) as well as crosslinking can be singled out. An attempt is made to calculate the chronological order of appearance of crosslinking and oxidation products (detectable par IR). Two elastomers - EPDM and polycyclooctene - are studied.

RELEASE OF PYRIDINE ALDOXIME CHLORIDE Gupta D C; Sumana G; Jain R India,Defence Research & Development Organisation; Jiwaji,University Details are given of the hydrolytic polycondensation of a series of polysiloxanes and their copolymers. Characterisation was undertaken using intrinsic viscosity, IR spectroscopy, and NMR. The controlled release of pyridine aldoxime chloride from the polymers is discussed. 23 refs.

EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

INDIA

Accession no.706025

Accession no.702896

Item 205 IRC ’98. Conference proceedings. Paris, 12th-14th May 1998, p.353-4. 012 INFLUENCE OF CARBON BLACK FILLERS ON CROSSLINK DENSITY Kelm J; Tobisch K BAM Federal Institute for Materials Research & Testing (AFICEP; Societe de Chimie Industrielle)

Item 207 Journal of Polymer Science : Polymer Physics Edition 36, No.15, 15th Nov.1998, p.2805-10 DIFFERENTIAL SCANNING CALORIMETRY(DSC) AND RAMAN SPECTROSCOPY STUDY OF POLYDIMETHYLSILOXANE(PDMS) Soutzidou M; Panas A; Viras K Athens,National University; Athens,Kapodistrian University; Manchester,University

Crosslink density is an extremely important factor in determining physical properties of vulcanisates. In considering the significance of crosslink density, it is necessary to distinguish between the apparent concentration of physical crosslinks and the concentration of chemically discrete crosslinks which result directly from vulcanisation. Crosslink density or intercrosslink chain density is frequently calculated from equilibrium swelling data or from stress-strain data. The separation of chemical crosslinks can be obtained using the ideas of Mullins. Carbon black introduces some deviations in these experiments because of the interactions of polymer chains and the carbon black particles. The original formulas for swelling and stress-strain are used in this case in a modified version introducing correction terms. A more recent technique for the measurement of intercrosslink chain density is the 1H NMR relaxation method. This method takes the non-exponentiality of the decay into account which contains the information on the slight anisotropy of the movement of intercrosslink chains. This small anisotropy is the base for estimating the intercrosslink chain density. The separation of entanglements and chemical crosslinks can be obtained by measuring a corresponding uncured sample EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.706007 Item 206 Journal of Applied Polymer Science 70, No.9, 28th Nov.1998, p.1837-46 SYNTHESIS AND CHARACTERISATION OF POLYSILOXANES FOR CONTROLLED

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PDMS was studied by laser Raman spectroscopy and DSC. The Si-O-Si skeletal model at 489/cm and the C-Si-C deformation bands at 188/cm and 158/cm were studied as functions of temp. from ambient to -130C and the effects of temp. were interpreted in accordance with results from thermal analysis. The crystallinity of PDMS was found to depend markedly on cooling conditions and it was possible, by careful thermal treatment, to achieve a high-melting form (Tm -36C). The Raman spectra of PDMS contained a number of bands that were sensitive to the crystallinity of the sample. Of these, the two Si-O-Si skeletal deformation bands offered the best prospect of quantitative use via the peak height intensity ratio. 36 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GREECE; UK; WESTERN EUROPE

Accession no.702740 Item 208 Journal of Applied Polymer Science 70, No.7, 14th Nov.1998, p.1371-83 SOLID-STATE CARBON-13 NMR STUDIES OF CHANGES IN CROSSLINKED CARBON STRUCTURE OF NATURAL RUBBER DURING HEATING UNDER AIR AND NITROGEN ENVIRONMENTS Parker D D; Koenig J L Case Western Reserve University The chemical changes that occur in thermal degradation of sulphur-cures NR were investigated using carbon-13 NMR analysis. The changes in concentration of different crosslink structures under thermooxidative conditions were examined. Samples were heat aged at different temperatures

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under both air (oxygen) and nitrogen environments to observe differences in crosslink structure due to temperature and thermooxidative degradation. 26 refs. USA

Accession no.702164 Item 209 ITEC ’96 Select. Conference proceedings.. Akron, Oh., 1996, p.21-32. 6T REVIEWING WAYS OF ANALYZING POLYMERS IN RUBBER COMPOUNDS Frisone G J; Schwarz D L; Ludwigsen R A Smithers Scientific Services Inc. (Rubber & Plastics News) A series of round robin tests was used to evaluate the various techniques currently used in analytical laboratories for the investigation of unknown rubber compounds. The analytical method for the analysis was determined by the participating laboratory, and a single technique only was used. A secondary objective of the study was to explore the variations in sample preparation, instrumentation parameters and data reporting. Results are discussed and analysed of six passenger tyre tread stock formulations, which were provided to each of 12 participating laboratories. USA

Accession no.701527

Item 211 Macromolecules 31, No.19, 22nd Sept.1998, p.6409-16 INFLUENCE OF END GROUP AND MOLECULAR WEIGHT ON BR FINGERPRINT SECONDARY ION MASS SPECTRA Eynde X V; Bertrand P; Dubois P; Jerome R Louvain,Universite Catholique; Liege,University BR samples of different molecular weight were synthesised by anionic polymerisation initiated by butyllithium. They were analysed by TOF-SIMS to investigate the sensitivity of this method toward the butyl end group and toward the molecular weight. Other molecular weight calibration methods were also used and are discussed in terms of their accuracy and physical meaning. 37 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.699439 Item 212 China Rubber Industry 45, No.9, 1998, p.564-7 Chinese THERMAL PYROLYSIS CHROMATOGRAPHY AND MASS SPECTROSCOPY OF POLYCHLOROPRENE Zhao Bangrong; Zhao Guiping 5 refs.

Item 210 Macromolecules 31, No.17, 25th Aug.1998, p.5690-4 SYNTHESIS OF MODEL MULTIGRAFT COPOLYMERS OF BUTADIENE WITH RANDOMLY PLACED SINGLE AND DOUBLE POLYSTYRENE BRANCHES Xenidou M; Hadjichristidis N Athens,University Model multigraft copolymers of butadiene and styrene with randomly placed trifunctional, poly(butadiene-graftstyrene) and tetrafunctional branchpoints, poly(butadienegraft-two styrene chains), were synthesised by hydrosilylation of polybutadiene about 92 wt% 1,4) with dimethylchlorosilane and methyldichlorosilane, respectively, followed by reaction of the resultant siliconchloride groups along the backbone with polystyryllithium. The extent of hydrosilylation was controlled by appropriate adjustment of the silane/double bond ratio. Characterisation carried out by size exclusion chromatography (UV and refractive index detectors), low angle laser light scattering, differential refractometry and NMR spectroscopy indicated that the synthesised branched molecules have a high degree of molecular and compositional homogeneity. 23 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GREECE; WESTERN EUROPE

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CHINA

Accession no.699142 Item 213 China Rubber Industry 45, No.9, 1998, p.524-7 Chinese CALCULATION FOR CRYSTALLINITY OF POLYCHLOROPRENE(CR) VULCANIZATE BY PEAK SEPARATION OF X-RAY DIFFRACTION(XRD) Zhang Yimin; Du Baoshi; Liu Fang Zhengzhou,University; Zhengzhou,Cable Works College Based on the XRD theory, a calculation formula for the crystallinity of CR vulcanisate was deduced from the separation between the crystallinity peak and the noncrystallinity scattering peak of CR vulcanisate by XRD, the derivation of the correction factors for crystallinity peak strength and non-crystallinity scattering peak strength and the composition of the crystallinity diffraction strength. The resultant formula was used to study the relationship between the crystallinity of CR vulcanisate and its curing time. 6 refs. CHINA

Accession no.699133

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References and Abstracts

Item 214 Elastomery 1, No.6, 1997, p.20-6 Polish DEVELOPMENT OF TESTING PROCEDURE OF PETROLEUM WAXES STRUCTURE Kleps T; Parys T; Piaskiewicz M STOMIL The structure of petroleum (paraffin) waxes is considered to be the fundamental feature characterising their efficiency as agents for protection of rubbers against ozone attack. A method for testing of the structure of such waxes is described which involves optical microscopy, DSC and gas chromatography. It is shown that the proposed procedures permit study of the crystalline and chemical structures of the waxes. The gas chromatography method permits calculation of the content of paraffin hydrocarbons in the range from 17 to 43 carbons. The content of normal and non-normal hydrocarbons for each carbon number can also be determined. 11 refs. EASTERN EUROPE; POLAND

Accession no.699077 Item 215 Elastomery 2, No.3, 1998, p.18-25 Polish PHYSICOCHEMICAL ANALYSIS OF RUBBER AND RAW MATERIALS Kleps T STOMIL Methods for studying the physicochemical properties of raw materials are discussed, together with a general scheme for analysis of rubber compounds. A method for running the investigations is outlined. The basic standards in the range of study of rubber and raw materials are given. 16 refs. EASTERN EUROPE; POLAND

Accession no.699070 Item 216 Luntai Gongye 18, No.10, 1998, p.612-4 Chinese ANALYSIS OF TACKLESS RUBBER PARTS Wang Dengxiang Shanghai Tire & Rubber Group Corp.Ltd. Analysis of tack-free tyre parts showed that the main factors which caused the tack-free rubber parts were sulphur blooming and extended storage period. The necessary instruments for analysis included a microscope with 60-fold magnification, an IR spectrometer and a UV spectrometer. A flow diagram of surface analysis is presented, the examining procedure of sulphur and nonsulphur blooming is described and the causes of the

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surface substances appearing in the tack-free rubber parts are discussed. CHINA

Accession no.699053 Item 217 China Synthetic Rubber Industry 21, No.5, 1998, p.266-70 Chinese APPLICATIONS OF THERMAL ANALYSIS IN THE RUBBER INDUSTRY Han F; Yin R Shenyang,Rubber Research & Design Institute A brief review is presented of the applications of thermal analysis in the rubber industry. Details are given of the main composition of vulcanisates, the selection of plasticisers and antiagers in formula design. The monitoring of vulcanisation and ageing of mixtures is discussed. 13 refs. CHINA

Accession no.697428 Item 218 Macromolecules 31, No. 16, 11th Aug. 1998, p.5529-35 DIFFUSION OF GASES IN SILICONE POLYMERS. MOLECULAR DYNAMICS Charati S G; Stern S A Syracuse,University Diffusion coefficients of helium, oxygen, nitrogen, carbon dioxide and methane at 300K in four silicone polymers, namely, poly(dimethylsiloxane), poly(propylmethylsiloxane), poly((trifluoropropyl)methylsiloxane), and poly(phenylmethylsiloxane), were estimated by molecular dynamics simulations. The estimated diffusion coefficients decrease with increasing size of the polymer side chains and of the penetrant molecules, as was also found experimentally. The estimated diffusion coefficient for helium in poly(dimethylsiloxane) is consistent with its experimental value. The values of the estimated diffusion coefficients for the other gas/silicone systems considered in this study were within 40-60% above or below the corresponding experimental values. The diffusion mechanism and some problems associated with the estimation of gas diffusion coefficients in polymers by molecular dynamics simulations are discussed. Tg and density data are shown for the polymers. 35 refs. USA

Accession no.696683 Item 219 Polymer 39, No.21, 1998, p.5053-7 HIGH RESOLUTION ELECTRON MICROSCOPY STUDY OF SINGLE CHAIN SINGLE CRYSTALS OF GUTTA PERCHA

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Fengyu Su; Lizhi Liu; Enle Zhou; Jianyu Huang; Renyuan Qian Chinese Academy of Sciences Single chain single crystals of gutta percha were prepared and were studied by means of electron diffraction and high-resolution electron microscopy (HREM). Electron diffraction patterns showed that the single chain single crystal was of a new crystalline modification, the delta form. HREM images showed that there was a defect region in the crystal showing a vague lattice image, but that the defect did not affect the coherence of the whole crystal lattice. The results were discussed with reference to the crystal formation and melting processes. 7 refs. CHINA

Accession no.696598 Item 220 Food Additives and Contaminants 15, No.1, 1st Jan.1998, p.79-83 COMBINED GC AND SNIFFING PORT ANALYSIS OF VOLATILE COMPOUNDS IN RUBBER RINGS MOUNTED ON BEER BOTTLES Linssen J P H; Rijnen L; Legger-Huiysman A; Roozen J P Wageningen,Agricultural University Two types of rubber rings used on clasps of swing top beer bottles were investigated for the presence of volatile compounds. Samples were incubated under different conditions and after dynamic headspace sampling were analysed by combined GC and sniffing port analysis. 7 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.695962 Item 221 Analytica Chimica Acta 371, No.1, 1998, p.89-96 QUANTITATIVE ANALYSIS OF NITRILE RUBBER/CHLOROPRENE BY PYROLYSIS/GAS CHROMATOGRAPHY/MASS SPECTROMETRY Fuh M R S; Gim-Yu Wang Soochow,University Studies were conducted of the use of the above combination of techniques for analysis of nitrile rubber(NBR)/chloroprene rubber(CR) materials. The pyrolysis products of nitrile rubber and chloroprene were identified and a reaction mechanism proposed. The peak ratio of 1-chloro-4-(1-chloroethenyl)cyclohexene and benzonitrile was used for quantitative measurement of CR/NBR composition in vulcanised samples. Good linearity and recovery were achieved. A series of vulcanised CR/NBR blended rubber materials was analysed using this method. Reasonable agreement between the estimated and the actual CR composition of these commercial rubber materials was obtained. 10 refs. TAIWAN

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Item 222 Journal of Applied Polymer Science 69, No.8, 22nd Aug. 1998, p.1557-61 SYNTHESES AND PROPERTIES OF SILICONE RUBBER/ORGANOMONTMORILLONITE HYBRID NANOCOMPOSITES. Shengjie Wang; Chengfen Long; Xinyu Wang; Qiang Li; Zongneng Qi Chinese Academy of Sciences Silicone rubber/organomontmorillonite hybrid nanocomposites were prepared using a melt-intercalation process, and characterised by x-ray diffraction, transmission electron microscopy and thermogravimetric analysis. The organomontmorillonite particles exfoliated to a thickness of approximately 50 nm, and were uniformly dispersed within the silicone rubber matrix. The mechanical properties and thermal stability of the prepared materials were very close to those of aerosilicafilled silicone rubber. 10 refs. CHINA

Accession no.693602 Item 223 Rubber Chemistry and Technology 71, No.2, May/June 1998, p.300-9 FTIR ANALYSIS OF SILICA-FILLED NATURAL RUBBER Kralevich M L; Koenig J L Case Western Reserve University The interactions of silica filler in zinc-activated, sulphurvulcanised cis-1,4-polyisoprene(IR) were characterised using FTIR-ATR spectroscopy. The variables examined were increased levels of silica and quality of mixing of the batch. The increased silica level resulted in band broadening and a frequency shift to lower wavenumbers of the silica absorbance region due to a combination of physical and chemical adsorption of the rubber and parts of cure system on the silica surface. The peaks that appeared near 1040 and 1017/cm were attributed to physical interactions between silica and the NR. Some chemical bonding of the IR was, however, present as a result of a free radical reaction that took place during the milling process. Inefficient mixing had an effect comparable with adding less filler, according to the above results, i.e. there was less ‘effective’ filler in the poorly mixed samples because poor dispersion promoted agglomeration of the polar silica in the non-polar hydrocarbon rubber. 21 refs. USA

Accession no.692440 Item 224 NRC 98 - Nordic Rubber Conference 1998. Conference proceedings. Halmstad, Sweden, 4th-5th June 1998, paper 4. 012 ELASTOMERS IN CONTACT WITH FOOD

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References and Abstracts

Jolly A Rapra Technology Ltd. (Sveriges Gummitekniska Forening; NGTR) This paper outlines migration studies undertaken with regard to elastomeric materials in contact with food. The materials studied were natural rubber, nitrile rubber, EPDM, fluoropolymer and silicone.

DSC. The samples were prepared using an immobilised titanium-magnesium catalyst and a random copolymer based on BR prepared with a homogeneous vanadium-containing catalyst used as a reference material. 34 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; RUSSIA; WESTERN EUROPE

Accession no.689363

SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.692111 Item 225 Adhesive Technology 15, No.2, June 1998, p.30-2 TESTING RUBBER-TO-METAL BONDED PARTS Jacks J Acadia Polymers Inc. The use of X-ray photoelectron spectroscopy and scanning electron microscopy to deduce that the failure of a rubberto-metal bonding application is caused by premature crosslinking of the adhesive is described. By eliminating other possible causes of debonding, such as contamination, a more robust manufacturing process is developed. USA

Accession no.689881 Item 226 Journal of Rubber Research 1, No.2, 1998, p.67-76 EPOXIDE GROUPS IN NATURAL RUBBER. I. CARBON-13 NMR STUDY OF OXIDATIVE DEGRADED RUBBERS Eng A H; Tangpakdee J; Kawahara S; Tanaka A Y Rubber Research Institute of Malaysia; Tokyo,University Epoxide groups in NR, derived from oxidative degradation of the polymer, were found mainly to be in cis-configuration. The amount of trans epoxide increased with increasing degradation temperature of the NR. The presence of cis epoxide groups in low molecular weight fractions of NR, could be associated with by-products of oxidative degradation of the polymer. 12 refs. JAPAN; MALAYSIA

Accession no.689742 Item 227 Journal of Macromolecular Science B B37, No.4, 1998, p.431-50 STRUCTURE OF BR SYNTHESISED WITH A NEW CATALYST SYSTEM Antipov E; Podolsky Y; Plate N; Stamm M; Fischer E W Russian Academy of Sciences; Mainz,Max-PlanckInstitut The structure, phase composition, and temperature behaviour of two polybutadienes were studied by X-ray scattering and

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Item 228 Tire Technology International 1998, p.126-30 IDENTIFYING RUBBER BLENDS USING DTG CURVES Amraee I A; Aghafarajollah S H; Rahmani R Iran Tyre Manufacturing Co. Thermal gravimetry analysis is a successful technique for the identification of NR/BR and NR/SBR blends in a vulcanised compound. In thermal analysis, the type of elastomers in vulcanised rubber can be identified by the degradation mechanism of different elastomers. This comprehensive article supplies a detailed analysis of a new method of qualitative and quantitative identification of such blends, using a thermal gravimetric analyser, by means of standard curves obtained from DTG thermograms. Details of the experiment and methodology, together with test results and samples of comparisons of DTG curves are supplied. 3 refs. IRAN

Accession no.685073 Item 229 153rd ACS Rubber Division Meeting - Spring 1998. Conference preprints. Indianapolis, In., 5th-8th May,1998. Paper 41. 012 CARBON BLACK STRUCTURE: WHAT WE HAVE LEARNED FROM NEUTRON SCATTERING Hjelm R P; Gerspacher M; Yang H H Los Alamos National Laboratory; Richardson S.,Carbon Co. (ACS,Rubber Div.) Small-angle neutron scattering has provided information on the structure and shape of carbon black and the structure of carbon black networks in rubber composites. The problem for determining the structure of these materials by neutron scattering is to resolve scattering length density fluctuations from the components and also from voids and other defects in the material. Immersing the material with fluids having different amounts of deuteration - the method of contrast variation - can do this. The results and potential of the method in the materials science of carbon black and durable rubber products are reviewed. 7 refs. USA

Accession no.683258

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Item 230 153rd ACS Rubber Division Meeting - Spring 1998. Conference preprints. Indianapolis, In., 5th-8th May,1998. Paper 36. 012 LOW EXTRACTABLE LEAD STABILISERS Grossman R F Hammond Group,Halstab Div. (ACS,Rubber Div.) Lead-containing additives, including litharge, red lead, dibasic lead phthalate and dibasic lead phosphite, are used in EPDM, CPE, CSM, ECO and FKM elastomers to improve moisture resistance, heat stability and electrical properties. Although generally non-migratory, such additives when extracted under vigorous conditions, such as in the EPA Toxic Characteristic Leaching Procedure, may yield sufficient soluble lead that product scrap would be classed as hazardous waste. This forms an impediment to transport to sites for recycling. Modified lead stabilisers have been developed such that reaction products arising from stabilisation are extremely insoluble. The effect is to lower dramatically TCLP lead extraction. 10 refs. USA

Accession no.683253 Item 231 153rd ACS Rubber Division Meeting - Spring 1998. Conference preprints. Indianapolis, In., 5th-8th May,1998. Paper 23. 012 MICROSCOPIC IMAGE ANALYSIS OF ELASTOMERS CAN INFER PHYSICAL PROPERTIES DiFoggio R; McElrath K O; Tisler A L; Ball J W Exxon Chemical Co. (ACS,Rubber Div.) Immiscible elastomers are often blended together. The ways in which the elastomer ingredients are mixed together and how they are cured make a big difference in the resulting morphologies of the microscopic elastomer domains, even if one starts out with the same set of ingredients. Distinct micron-sized elastomer domains can be observed for such blends by using transmission electron microscopy or atomic force microscopy. By applying image analysis techniques, the number, shapes and areas of these domains can be quantified. Good correlations are found between these quantitative image parameters and physical properties such as Shore A, adhesion, DeMattia crack length and fatigue to failure. These correlations demonstrate the importance of microscopic morphology to the performance of elastomer blends. 5 refs. USA

Accession no.683241 Item 232 China Synthetic Rubber Industry 21, No.3, 1998, p.178-9 Chinese

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EFFECT OF BENTONITE ON UNACCELERATED SULFUR VULCANIZATION OF SBR Peng Shuwen; Zhao Zhenmin; Lu Jianchun; Jiang Chunxian; Huang Yingchao Jilin Chemical Industry Corp. The addition of 20 phr or less of bentonite to a nonaccelerated SBR/sulphur composition was shown to decrease the scorch time, while addition of more than 20 phr bentonite had no effect on scorching. The addition of bentonite to the composition had little effect on the rate of vulcanisation. From IR spectroscopy, it was found that bentonite not only accelerated the formation of rubber ions but also absorbed rubber ions and that the two actions could offset each other. 6 refs. CHINA

Accession no.682783 Item 233 Journal of Rubber Research 1, No.1, 1998, p.14-21 BRANCHING IN NR Tangpakdee J; Tanaka Y Tokyo,University of Agriculture & Technology The number of branch-points in NR was analysed for the rubber from deproteinised fresh-field and high-ammonia latices using carbon 13 NMR and osmometric measurement before and after transesterification of the rubber. 21 refs. JAPAN

Accession no.682732 Item 234 Rubber Chemistry and Technology 71, No.1, March-April 1998, p.53-61 WET SKID PROPERTIES OF FILLED RUBBERS AND THE RUBBER-GLASS TRANSITION Heinrich G; Dumler H B Continental AG The physical relationships between wet skid resistance of filled rubber compounds and the dynamics of the corresponding bulk polymers in the rubber-glass transition zone were investigated. It was shown how wet grip data and their ratings correlate with dynamic Tgs in the NMR time scale for the spin-spin relaxation time that characterises the relaxation of transverse magnetisation. The corresponding frequency was independent of the Larmor frequency of the NMR experiment. Some molecular aspects of the network dynamics in the transition zone were considered. 24 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.682555

© Copyright 2001 Rapra Technology Limited

References and Abstracts

Item 235 Rubber Chemistry and Technology 71, No.1, March-April 1998, p.17-25 REFLECTOMETRY - A NEW METHOD OF MEASURING FILLER DISPERSION Gerspacher M; Nikiel L; Yang H H; O’Farrell C P Richardson S.,Carbon Co. A new method of measuring carbon black dispersions in rubber is presented. The method is based on measurement of the light reflectivity from the rubber sample using standard equipment used in the evaluation of tint strength of carbon black (ASTM D3265). The method can be used for cured and uncured samples. It was shown that samples with better dispersed carbon black reflect less light compared with samples with poor carbon black dispersion. 7 refs. USA

Accession no.682552 Item 236 Polymer Engineering and Science 38, No.4, April 1998, p.689-92 MECHANISM OF TRIALLYLCYANURATE AS A COAGENT IN EPDM PEROXIDE VULCANISATION Murgic Z H; Jelencic J; Murgic L Zagreb,University The reaction mechanism of EPDM peroxide vulcanisation, in the presence of triallyl cyanurate as a coagent, was studied by IR spectroscopy and equilibrium swelling. Coagent triallyl cyanurate was added to prevent the scission of polymer chains during the curing process. 16 refs. CROATIA

Accession no.681703 Item 237 Kautchuk und Gummi Kunststoffe 51, No.5, 1998, p.364-9 German COMPARATIVE INVESTIGATIONS OF THE CROSSLINK DENSITY OF ELASTOMERS Kelm J; Tobisch K; Leisen J BAM; Georgia,Institute of Technology The obtaining of crosslink density or intercrosslink chain density of natural rubber vulcanisates with and without carbon black is discussed, by means of the H-NMR transversal relaxation, the analysis of uniaxial stress-strain measurements, the investigation of swelling properties and in peroxide-cured samples by calculation. The aim of the study is to compare the results obtained with these techniques in order to find out the limits and possibilities. To this end, several vulcanisation systems with different types and concentrations of carbon black were investigated to provide a consistent idea of network characteristics. 15 refs.

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EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; USA; WESTERN EUROPE

Accession no.681312 Item 238 Rubber and Plastics News 27,No.20, 4th May 1998, p.28-31 ANALYZING COMPOUNDS USING PYROLYSIS METHOD Ghebrehiwet N; Ghebremeskel N; Hendrix C Ameripol Synpol Corp. The use is discussed of pyrolysis and gas chromatography in the characterisation of rubber blends in the presence of carbon black and fillers. Experiments were carried out on binary and tertiary elastomeric blends containing natural rubber, polybutadiene and SBR. The method is claimed to identify sub-milligram amounts of binary and tertiary mixtures of vulcanised and unvulcanised rubber materials, with very little sample preparation. 15 refs. USA

Accession no.681143 Item 239 Journal of Applied Polymer Science 68, No.11, 13th June 1998, p.1821-8 INFLUENCE OF SILICA CONTENT ON MIGRATION OF ANTIDEGRADANTS TO THE SURFACE IN NR VULCANIZATES Choi S-S Kumho R&D Center The migration of antidegradants to the surface in silicafilled natural rubber (NR) vulcanisates was studied with migration-generating equipment using a vacuum technique. The antidegradants studied were 2,6-di-t-butyl4-methyl phenol (BHT), N-phenyl-N-isopropyl-pphenylene-diamine (IPPD), N-phenyl-n-(1,3dimethylbutyl-p-phenylenediamine (HPPD) and wax. The migration rate was dependent upon the silica content, the rates for BHT, IPPD and HPPD decreasing with increasing silica content over the range of 30 to 70 phr. IPPD migrated faster than BHT and HPPD, whilst BHT migrated faster than HPPD at 60 and 80C, but slower than HPPD at 100C. The lower molecular weight waxes migrated faster than those of higher molecular weight. The activation energies for surface migration were calculated. 14 refs. SOUTH KOREA

Accession no.680612 Item 240 Carbon Black Science and Technology. 2nd edition. New York, N.Y., Marcel Dekker, 1993, p.89-173. 51B MICROSTRUCTURE, MORPHOLOGY AND GENERAL PHYSICAL PROPERTIES Hess W M; Herd C R

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Columbian Chemicals Co. Edited by: Donnet J-B; Bansal R C; Wang M-J (Centre de Recherches sur Physico-Chimie Surf.Sol.; Panjab,University; Degussa AG) The physical properties of carbon black have received considerable attention over the past 70 years or more, as the reinforcement of elastomers, the protection of plastics from UV degradation, and the blackness and tint properties of paint and ink coatings are all highly dependent on particle size and other aspects of carbon black morphology and microstructure. All of these properties have been the subject of extensive reviews. Each of these reviews provide additional information in the specific areas cited. 269 refs. USA

Accession no.679938 Item 241 Polymer Technology for the New Millennium. Conference proceedings. Blue Mountains, Australia, 12th-15th Oct.1997, paper 19. 012 HIGH RESOLUTION SOLID STATE 1H NMR SPECTROSCOPY IN THE INVESTIGATION OF THE FILLER-RUBBER INTERACTION Dutta N K; Choudhury N R; Haidar B; Vidal A; Donnet J B; Delmotte L; Chezeau J M Monash,University; South Australia,University; CNRS; Ecole Nationale Superieure de Chimie de Mulhouse (Australasian Plastics & Rubber Institute) A new approach to investigate filler-polymer interaction by using solid state high-resolution high speed 1H magic angle spinning NMR spectroscopy is described. Pulsed NMR measurements are carried out on pure SBR, and on solvent-extracted carbon gels. High resolution of the samples may be achieved either at higher temperature using lower spinning rate, or at room temperature by using very high rate of spinning. The high resolution proton spin-spin relaxation time, Ts is measured successfully for each of the principle resonance species present in the elastomer. This measurement reveals an insight into the site-specific nature of the polymer/filler interaction. The relative immobilisation of the different protons shows the methine proton to be much more immobilised than the aromatic and methylene species. The effect of filler loading, equilibration time and severity of extraction on filler/rubber interactions is also discussed These studies provide a very important understanding in the structure and formation mechanism of carbon gel in filled elastomeric systems. 18 refs. AUSTRALIA; EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; USA; WESTERN EUROPE

Accession no.679813 Item 242 Polymer Technology for the New Millennium. Conference proceedings.

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Blue Mountains, Australia, 12th-15th Oct.1997, paper 18. 012 DIRECT AND INDIRECT SURFACE ANALYSIS OF DIFFUSION AND MIGRATION OF ADDITIVES IN AUTOMOTIVE WINDOW SEAL COMPONENTS Dimopoulos M South Australia,University (Australasian Plastics & Rubber Institute) Automotive window seal compounds are highly filled and highly extended EPDM rubber based compounds with coatings. Most rubber formulations are complex mixtures of different additives. It has often been observed that the additives diffuse and migrate to the surface with time resulting in loss of coating adhesion to the rubber. Therefore, it is necessary and important to identify the different additives diffusing and migrating to the surface and hence creating problems in adhesion. The standard automotive window seal formulation of Bridgestone is described. Migration of additives is studied with different samples by both direct and indirect surface analysis methods. Contact angle measurement and XPS are the direct surface probing techniques whereas indirect method involves rapid extraction of the additive from the surface with a solvent followed by gel permeation chromatography and FTIR analysis. 5 refs. AUSTRALIA

Accession no.679812 Item 243 Journal of Polymer Science : Polymer Chemistry Edition 35, No.16, 30th Nov.1997, p.3393-401 METHOD OF DETERMINING THE DEGREE OF BRANCHING FROM THE GEL PERMEATION CHROMATOGRAM FOR STAR-SHAPED SBS THERMOPLASTIC BLOCK COPOLYMERS Jeng-Ming Liu; Chi-Sheng Chang; Raymond ChienChao Tsiang Taiwan,National Chung Cheng University A GPC calculation method was developed for characterisation of star-shaped styrene-butadiene block copolymers. The method enabled determination of the degree of branching of the synthesised polymer without the need for a priori measurement of the true molec.wts. of the SBS star polymer and its linear polymeric arm. In order to illustrate the simplicity of this method, nearly monodisperse threearm and four-arm model star polymers were synthesised by linking living diblock polymeric arms of the PS-blockpolybutadiene type with silicon tetrachloride as the multifunctional linking agent. The good agreement between the degree of branching calculated from the GPC chromatogram and that actually measured by multiple angle laser light scattering corroborated the validity of the calculation method. 16 refs. TAIWAN

Accession no.679185

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References and Abstracts

Item 244 Rubber Chemistry and Technology 70, No.4, Sept./Oct.1997, p.671-80 SOLID-STATE CARBON-13 NMR STUDIES OF VULCANIZED ELASTOMERS. XVII. EFFECT OF CARBON BLACK GRADE ON THE NETWORK STRUCTURE IN NATURAL RUBBER VULCANIZATES Mori M; Koenig J L Case Western Reserve University The vulcanisation chemistry and network formation of carbon black-filled NR vulcanised with sulphur and N-tertbutylbenzothiazole sulphenamide were studied using solidstate carbon-13 NMR and equilibrium swelling measurements. A reduction in the sulphur rank of the A1 type sulphide and increased proportion of B1 type polysulphide were observed when the carbon black concentration increased in NR. At the same loading level, the structural property or grade of carbon black did not qualitatively affect the type of sulphide formation. The efficiency of the intermolecular crosslinking over the whole range of sulphurisations was 45.7% for the unfilled vulcanisate. The extent of the chemical sulphurisation reactions was constant with black incorporation, while the total network increased with increases in the black loading. The amount of physical entanglements was found to increase linearly with the carbon black concentration. 16 refs. (Fall ACS Rubber Division Meeting, Louisville, Oct.1996) USA

Accession no.679135 Item 245 Rubber Chemistry and Technology 70, No.4, Sept./Oct.1997, p.549-59 MICROSTRUCTURE OF NATURAL RUBBER LATEX FILMS Cook S; Cudby P E F; Davies R T; Morris M D Tun Abdul Razak Research Centre An electron microscopy technique which was previously used to visualise the crosslinked regions in vulcanised blends of dry rubber was applied to films made from NR latex. The method involved swelling the latex film with styrene, polymerising the styrene, sectioning the sample and then staining with osmium tetroxide to reveal the rubber network when observed by TEM. The micrographs showed the higher ratio of interparticle to intraparticle crosslinks in a sulphur post-vulcanised film as compared with a sulphur prevulcanised film. They also showed that, as in dry rubber films, the mesh size of the visible rubber network correlated with the crosslink density of the rubber. The technique also revealed that the crosslink distribution in peroxide prevulcanised latex was significantly different from that in latices prevulcanised using sulphur or radiation. 13 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.679125

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Item 246 Polimeros: Ciencia e Tecnologia 7, No.1, Jan./March 1997, p.37-43 Portuguese APPLICATIONS OF FOURIER TRANSFORM INFRARED SPECTROSCOPY IN THE ISOMERIC CHARACTERISATION OF HYDROXYLTERMINATED POLYBUTADIENES USED IN THE SYNTHESIS OF PU PROPELLANTS Takahashi M F K; Polito W L Brazil,Instituto de Aeronautica e Espaco; Sao Carlos,Instituto de Quimica The distribution of configurational isomers in hydroxylterminated polybutadiene polyols used in the manufacture of PU propellants was determined by Fourier transform IR spectroscopy using both solution and liquid film techniques. There was good agreement between the results obtained using the two techniques and with those obtained by NMR spectroscopy. 21 refs. BRAZIL

Accession no.679095 Item 247 TAPPI 1997 Polymers, Laminations and Coatings Conference. Conference Proceedings. Book 2. Toronto, Ontario, 24th-28th Aug.1997, p.529-32. 012 FILM FORMATION OF POLYMER DISPERSION FILM OBSERVED BY AFM Kimpimaki T; Savolainen A Tampere,University of Technology (TAPPI) Styrene-butadiene copolymer dispersions were examined for relationships between drying temperature, particle coalescence and barrier properties. Coalescence of adjacent polymer particles was determined by atomic force microscopy for coatings dried on board and for films dried inside an aluminium bowl. The samples were dried in an air circulation oven for various times at temperatures from 50 to 150C. High drying temperatures or prolonged drying times increased the coalescence of the particles, and the angle between adjacent particles (coalescence angle) decreased with proceeding coalescence. The coalescence angle and the water vapour transmission rate appeared to have good equivalence, indicating that the barrier properties depended mainly on the drying conditions. 2 refs. CANADA; FINLAND; SCANDINAVIA; USA; WESTERN EUROPE

Accession no.679015 Item 248 Polymer Bulletin 40, Nos.4-5, April/May 1998, p.525-32 THERMAL STABILITIES OF END GROUPS IN HYDROXYALKYL TERMINATED POLYDIMETHYLSILOXANE(PDMS) OLIGOMERS

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References and Abstracts

Yilgor I; Yilgor E Istanbul,Koc University The thermal stabilities of alpha,omega-hydroxypropyl, alpha,omega-hydroxybutyl, alpha,omega-2-hydroxypentyl and alpha,omega-hydroxyhexyl terminated PDMS oligomers were studied. Hydroxypropyl and hydroxybutyl terminated PDMS oligomers showed degradation upon heating, through the loss of functional end groups as determined by FTIR spectroscopy and GPC. alpha,omegaHydroxyhexyl and alpha,omega-2-hydroxypentyl terminated PDMS oligomers were stable under similar conditions. Instability of the end groups was due to the backbiting of the terminal silicon in the PDMS by the primary hydroxyl oxygen, leading to the formation of 5and 6-membered, stable, heterocyclic compounds. Loss of end groups also resulted in a dramatic increase in the molec.wts. of the oligomers produced, as determined by GPC. 19 refs. TURKEY

Accession no.678430 Item 249 Macromolecules 31, No.8, 21st April 1998, p.2468-74 MALDI-TOF-MS COPOLYMER ANALYSIS: CHARACTERIZATION OF A POLYDIMETHYLSILOXANE-COPOLYHYDROMETHYLSILOXANE AS A PRECURSOR OF A FUNCTIONALIZED SILICONE GRAFT COPOLYMER Servaty S; Koehler W; Meyer W H; Rosenauer C; Spickermann J; Raeder H J; Wegner G; Weier A Max-Planck-Institut fuer Polymerforschung; Goldschmidt Th.,AG The above copolymers was characterised with respect to chain length distribution, heterogeneity of chemical composition and sequence distribution using size exclusion chromatography(SEC), proton and silicon-29 NMR and MALDI-TOF-mass spectroscopy. As a result of ambiguities in the peak assignment, the deconvolution of the mass spectrum into the bivariate copolymer distribution was not possible. The expected mass spectrum was also computed from the SEC and NMR data. It was then mapped out onto the measured one and an almost perfect agreement was found within the peak resolved low molar mass range, leaving only a small number of adjustable parameters. As a result, it could be shown that a large number of chains contained no functionalisable units at all. 34 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.678346 Item 250 China Synthetic Rubber Industry 21, No.2, 1998, p.114

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Chinese EPOXIDATION OF LOW VINYL BR RUBBERS Wang Y; Qi S; Song X; Guan C; Gu M Dalian,University of Technology Details are given of the preparation of high relative molecular mass epoxide low vinyl BR rubber with different degrees of epoxidation in either alkane or aromatic solvents under different reaction conditions. Characterisation was undertaken using DSC and NMR. CHINA

Accession no.676884 Item 251 China Rubber Industry 45, No.3, 1998, p.131-6 Chinese STUDY ON PROPERTIES OF MODIFIED MVBRS. II. STUDY ON TG AND DYNAMIC MECHANICAL PROPERTIES Li Yang; Liu Huiming; Gu Mingchu Beijing Yanshan Petrochemical Co.; Dalian,University of Science & Technology The Tg and the dynamic mechanical properties of four kinds of modified medium polybutadiene rubbers (MVBRs) were systematically investigated. The results showed that L-B-MVBR had better dynamic mechanical properties and lower heat build-up; the star-branched structure and the increase of molecular weight and 1,2polybutadiene content were beneficial to form the microphase separated structure; the appropriate ratio of the 1,2-polybutadiene block to the 1,4-polybutadiene block resulted in a remarkable microphase separated structure. 4 refs. CHINA

Accession no.675016 Item 252 Journal of Applied Polymer Science 67, No.13, 28th March 1998, p.2131-40 THERMAL CROSSLINKING OF BR AT ULTRAHIGH PRESSURES Zeng X-R; Ko T-M South China,University of Technology; Singapore,National University BR samples were simultaneously compressed and annealed between 25 and 180C. Solid-state carbon 13 NMR and FTIR showed that some C=C bonds in the BR were opened to form the crosslinking network structures with C-C linkages and that partial cis-trans isomerisation took place during the treatments. Tg and crystallinity were determined using DSC. 24 refs. CHINA; SINGAPORE

Accession no.672803

© Copyright 2001 Rapra Technology Limited

References and Abstracts

Item 253 Rubber Chemistry and Technology 70, No.3, July/Aug.1997, p.468-518 NMR IMAGING OF ELASTOMERS: A REVIEW Bluemler P; Bluemich B Aachen,Lehrstuhl fuer Makromolekulare Chemie A review is presented of the literature on the use of NMR imaging for applied research in the field of elastomers and the versatility of the technique for various applications is demonstrated. A brief introduction to the principles of NMR imaging is first given. The possibilities of NMR for tailoring image contrast to specific parameters are then considered. Some examples are given of special contrast features in NMR images and the quantitative interpretation is discussed. The necessary hardware is reviewed. 158 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.671092 Item 254 Rubber Chemistry and Technology 70, No.3, July/Aug.1997, p.368-429 THIURAM- AND DITHIOCARBAMATEACCELERATED SULFUR VULCANIZATION FROM THE CHEMIST’S PERSPECTIVE; METHODS, MATERIALS AND MECHANISMS REVIEWED Nieuwenhuizen P J; Reedijk J; Van Duin M; McGill W J Leiden,University; DSM Research; Port Elizabeth,University Research methodologies for the investigation of the mechanism of vulcanisation are described and the reactivity of thiuram and dithiocarbamate chemicals is discussed. The mechanism and chemistry of both thiuramand dithiocarbamate-accelerated sulphur vulcanisation are then considered. The integration of the original mechanistic ideas from the 1960s and the results obtained in the past three decades are shown to lead to a more balanced appraisal of events during vulcanisation. Proposals for future research are made. 262 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; SOUTH AFRICA; WESTERN EUROPE

Accession no.671090 Item 255 Kautchuk und Gummi Kunststoffe 51, No.2, Feb.1998, p.118/21 German QUANTITATIVE ANALYSIS OF ANTIOXIDANTS IN ELASTOMERS BY SFE (SUPERCRITICAL FLUID EXTRACTION) Werthmann B; Neyen V; Milczewski F; Borowski R The total amount of solvent extracts by SFE is determined in seven vulcanised rubbers with different polarity. For

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comparison the rubber materials are extracted in accordance with DIN ISO 1407 (conventional method). The extracts are especially prepared and the amount of antioxidants analysed offline by high performance liquid chromatography under defined conditions. The results of SFE and conventional solvent extraction (Soxhlet extraction) are comparable, but the SFE offers more advantages. 10 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.670432 Item 256 Macromolecules 31, No.1, 13th Jan.1998, p.77-85 EFFECTS OF CARBON DIOXIDE SORPTION ON THE ROTATIONAL REORIENTATION DYNAMICS OF A MODEL SOLUTE DISSOLVED IN MOLTEN PDMS Niemeyer E D; Bright F V New York,State University The effects of polymer molecular weight, temperature, and carbon dioxide gas sorption on the rotational reorientation dynamics of a model solute dissolved in PDMS were investigated. Time-resolved fluorescence anisotropy measurements in PDMS polymers of various molecular weights were undertaken to determine the bisdibutylphenylperylenedicarboximide rotational dynamics. Correlations between bisdibutylphenylperylenedicarboximide rotational reorientational dynamics and PDMS bulk density are discussed. 35 refs. USA

Accession no.669402 Item 257 Macromolecules 30, No.26, 29th Dec.1997, p.8344-59 THERMAL AND QUENCHED FLUCTUATIONS OF POLYMER CONCENTRATION ON PDMS GELS Rouf-George C; Munch J-P; Schosseler F; Pouchelon A; Beinert G; Boue F; Bastide J Strasbourg,Universite Louis Pasteur; Strasbourg,Institut Charles Sadron; CNRS; Rhone-Poulenc Silicones The fluctuations of polymer concentration in highly crosslinked PDMS gels were studied as a function of swelling degree in a good solvent using neutron and light scattering techniques. The total scattering intensity was separated into the contributions arising from thermal and quenched fluctuations. A new picture for fluctuations of concentration in polymer gels is proposed and discussed in relation with recent models. 56 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.669365

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References and Abstracts

Item 258 China Synthetic Rubber Industry 21, No.1, 1998, p.53 MICELLES OF POLYSTYRENE-B-BUTADIENEB-STYRENE TRIBLOCK COPOLYMER IN BUTANONE STUDIED BY GPC Peijun J; Jian W; Jinshen W; Meiling Y; Lianghe S Chinese Academy of Sciences Polystyrene-b-butadiene-b-styrene triblock copolymer (SBS) can associate reversibly to form micelles in butanone which is a selective solvent for PS block. The micelles consist of a core of insoluble polybutadiene block and a shell of soluble polystyrene block. The size of SBS micelles is larger than that of the molecularly dissolved SBS, then SBS micelles elute faster than the copolymer chains in GPC columns. The apparent relative molecular mass, polydispersity, micelle mass ratio, association number (i.e. the number of copolymer chains forming a micelle), critical molecular concentration and critical molecular temperature of SBS micelles are studied by GPC. 1 ref. CHINA

Accession no.668632 Item 259 Journal of Applied Polymer Science 67, No.3, 18th Jan.1998, p.501-12 STRUCTURE AND MECHANICAL PROPERTIES OF NITRILE RUBBERS MODIFIED WITH IODINE Bielinski D M; Slusarski L; Wlochowicz A; Slusarczyk C Lodz,Technical University Nitrile rubbers, both common and hydrogenated, revealed some kind of ordering, as detected by wide angle X-ray spectroscopy. Strain-induced crystallisation was responsible for the enhanced degree of crystallinity for HNBR. In the case of NBR, another mechanism was proposed, namely specific interactions between carboncarbon double bonds from butadiene and cyano groups from acrylonitrile monomer units, leading to an ethylene diamine complex formation. Iodination reduced the degree of crystallinity of both materials; their stiffness increased as a result of modification, probably due to dipole-dipole interactions or hindering effects accompanying introduction of ‘large’ iodine atoms into the macromolecular structure. 19 refs. EASTERN EUROPE; POLAND

Accession no.665737

PHOTOELECTRON SPECTROSCOPY AND DYNAMIC CONTACT ANGLE MEASUREMENTS Lin Li; Chi-Ming Chan; Lu Tao Weng Hong Kong,University of Science & Technology Five NBR samples containing from 23 wt.% to 40 wt.% acrylonitrile were analysed by NMR to determine their triad and tetrad sequence distributions. Bulk compositions were determined precisely by NMR,.g. NBR-30 was 29.96 wt.% acrylonitrile. Surfaces were analysed by Xray photoelectron spectroscopy and solid surface tensions were determined by dynamic contact angle measurements. For NBR-23, NBR-29 and NBR-30, the surface fractions of acrylonitrile groups were less than in the bulk, whereas for NBR-35 and NBR-40, the surface compositions were very close to their bulk compositions. Comparison of sequence distribution and surface enrichment data shows that surface segregation of the butadiene group occurs in copolymers with a high intensity of the triad sequence (BBB). Surface segregation of the butadiene segments in NBR-23, NBR-29 and NBR-30 increased the dynamic contact angle values. There was a linear relationship between the contact angle and the acrylonitrile surface concentration. Relevance to oil resistance is suggested. 19 refs. HONG KONG

Accession no.663992 Item 261 Macromolecular Chemistry & Physics 198, No.11, Nov.1997, p.3485-98 LIGHT SCATTERING STUDY OF RANDOM DISORDER IN LIQUID CRYSTALLINE ELASTOMERS Clarke S M; Nishikawa E; Finkelmann H; Terentjev E M Cambridge,University; Freiburg,Universitat A structural study is reported of a non-uniform director texture in nematic and smectic liquid crystalline elastomers. Polarised light scattering was used to probe the equilibrium director correlations in the region of transition under stress between the opaque polydomain material and the transparent, macroscopically monodomain elastomer. Theoretical predictions were compared with experimental results for polyoxymethylsilylene. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; UK; WESTERN EUROPE

Accession no.663256 Item 260 Macromolecules 30, No.12, 16th June 1997, p.3698-700 EFFECTS OF SEQUENCE DISTRIBUTION OF POLY(ACRYLONITRILE-BUTADIENE) COPOLYMERS ON THE SURFACE CHEMICAL COMPOSITION AS DETERMINED BY X-RAY

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Item 262 Elastomery No.4, 1997, p.27-36 Polish DYNAMIC TG AS A CRITERION FOR THE WET SKID BEHAVIOUR OF TREAD COMPOUNDS

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References and Abstracts

Heinrich G; Rennar N; Dumler H Continental AG Details are given of an estimation of static and dynamic Tg of a series of rubbers by means of DSC, dynamic mechanical analysis and NMR. Wet skid resistance was also estimated. 20 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.663234 Item 263 China Synthetic Rubber Industry 20, No.6, 1997, p.350-2 Chinese EFFECT OF N,N’-METAPHENYL BISMALEIMIDE ON CROSSLINKING AND NETWORK STRUCTURE OF EPDM Luo Dongshan; Zhou Peng; Fan Hong; Wang Dizhen South China,University of Technology The influences of N,N’-metaphenyl bismaleimide (MPBM) on the crosslinking rate constant and activation energy in EPDM peroxide curing reaction were measured and calculated by MDR 2000 non-disc rheometer, oscillating disc rheometer and DSC. It was shown that MPBM could efficiently decrease the apparent activation energy of the reaction and increase the reaction rate and crosslinking density. The equilibrium stress-strain analysis and the equilibrium swelling test also showed that the structural parameters of EPDM vulcanisation network increased by the incorporation of MPBM. It was proved that MPBM with bifunctionality was an effective crosslinking assistant for EPDM rubber with saturated main chain. 4 refs. CHINA

Accession no.662837 Item 264 Journal of Materials Science 32, No.22, 15th Nov.1997, p.6119-26 DIELECTRIC SPECTROSCOPY - ANALYTICAL TOOL FOR MONITORING DETERIORATION DUE TO HIGH ENERGY RADIATION IN ETHYLENE PROPYLENE DIENE TERPOLYMER (EPDM) VULCANISATES Shah C S; Patni M J; Pandya M V Indian Institute of Technology The use of dielectric spectroscopy for monitoring the high energy radiation ageing and stabilisation of EPDM vulcanisates is demonstrated. The measurement of dielectric constants and dielectric losses in the frequency domain help to quantify the physicochemical changes in the bulk due to high energy irradiation. It is found that the relaxation time calculated using an empirical approach is exponentially related to the total exposed dose. A quantitative comparison of different antirads with a control vulcanisates is demonstrated by using parameters defined

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as relative efficiency indices (REI) and relative stability indices (RSI). Three types of REI parameters are defined and computed from dielectric measurements after irradiation over a period of time at a fixed frequency. These REI values are a good estimate of antirad efficiency for energy scavenging and transient charge scavenging. Two types of RSI parameters are defined and computed from the frequency scans of dielectric properties for a material exposed to various doses of gamma irradiation. These RSI values provide a good estimate of the rate and extent of changes in the physicochemical structure due to irradiation. A third type of RSI, computed from equilibrium swelling measurements, closely matches that obtained from dielectric data. It is concluded that the deterioration is predominantly created by a crosslinking reaction even after the addition of antirads. It is observed that polymeric antirads provide the highest efficiency stability. 15 refs. INDIA

Accession no.662366 Item 265 Kautchuk und Gummi Kunststoffe 50, No.11, Nov.1997, p.804-6 129 XENON NMR STUDY OF CARBON BLACKFILLED EPDM Sperling K; Veeman W S; Litvinov V M The investigation of carbon-black filled EPDM by means of 129 Xenon NMR spectroscopy is described. Unvulcanised EPDM is filled with three types of commercial available carbon blacks, differing in particle size and specific surface. 129 Xe NMR spectra indicate that Xe atoms are absorbed in the mobile EPDM domains of both filled and unfilled material. In addition, a resonance of Xe adsorbed in the bound rubber fraction is detected. From the chemical shift and line width of this resonance it is concluded that the EPDM chains around the carbon black particles have a strongly diminished mobility. 12 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.662345 Item 266 Adhesives Age 40, No.11, Oct.1997, p.36-8 SEM AND XPS TESTING AND ANALYSIS OF RUBBER-TO-METAL BONDED PARTS Jacks J Acadia Polymers This article examines the analysis of failure of bonding rubber to metal, looking in particular at scanning electron microscopy (SEM) testing, and X-ray photo-electron spectroscopy (XPS) testing. A case study example is discussed, and conclusions are drawn. USA

Accession no.661039

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References and Abstracts

Item 267 Industrial & Engineering Chemistry Research 36, No.11, Nov.1997, p.4763-7 HYDROCOPROCESSING OF SCRAP AUTOMOTIVE TYRES AND COAL. ANALYSIS OF OILS FROM AUTOCLAVE COPROCESSING Anderson L L; Callen M; Ding W; Liang J; Mastral A M; Mayoral M C; Murillo R Utah,University; CSIC Hydrocoprocessing of scrap automotive tyres and a lowrank coal was carried out in a magnetically stirred autoclave. Derived products were characterised using gas chromatography-mass spectrometry and thin layer chromatography with an FID detector. 21 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; USA; WESTERN EUROPE

Accession no.660828 Item 268 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints. Cleveland, Oh., 21st-24th Oct.1997, Paper 130, pp.17. 012 RAPID ANALYTICAL METHOD FOR THE DETERMINATION OF VOLATILE NNITROSAMINES IN BABY BOTTLE NIPPLES Andress M; Gurley T; Harsch S Abbott Laboratories (ACS,Rubber Div.) A new method for determining the concentration of nitrosamines in baby bottle nipples is described. The nitrosamines are purged out of the sample using a partial vacuum and heat, collected on a solid phase cartridge, eluted with methylene chloride and methanol, and measured by gas chromatography and thermal energy analysis. This method takes 3 to 4 hours to complete, compared to 2 to 3 days in the case of extraction procedures. 22 refs. USA

Accession no.659571 Item 269 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints. Cleveland, Oh., 21st-24th Oct.1997, Paper 123, pp.19. 012 HNBR AND LONG-TERM SERVICEABILITY IN MODERN AUTOMOTIVE LUBRICANTS. I. ANALYTICAL STUDY Tripathy B S; Smith K C Federal-Mogul Corp. (ACS,Rubber Div.) The mechanism responsible for the hardening of hydrogenated nitrile rubber automotive seal compounds on prolonged exposure to automatic transmission fluids at high temperature was investigated using Fourier transform IR spectroscopy. The increase in hardness was

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found to result primarily from chemical attack at the acrylonitrile (AN) sites. This chemical attack first resulted in the formation of isocyanide or isonitrile ions. The proposed mechanism involved crosslinking at the AN sites through the formation of isonitrile ions and the subsequent formation of imides. The isonitrile intermediate formed ionic bonds resulting in the formation of an ionomer once the concentration became sufficiently high. Ultimately these ions crosslinked to form imides in the presence of oxygen or water. It was proposed that the increase in hardness was due to the formation of the ionomer and the imides. 9 refs. USA

Accession no.659564 Item 270 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints. Cleveland, Oh., 21st-24th Oct.1997, Paper 96, pp.32. 012 BASIC STUDY OF CONTINUOUS ULTRASONIC DEVULCANIZATION OF UNFILLED SILICONE RUBBER Diao B; Isayev A I; Levin V Yu Akron,University,Inst.of Polym.Engineering (ACS,Rubber Div.) Unfilled polydimethyl siloxane vulcanisates were ultrasonically devulcanised under several processing conditions in an extruder with an ultrasound die attachment. Gel fraction and crosslink density measurements indicated that the rubber was partially devulcanised. The cure behaviour, rheological properties and structural characteristics of the devulcanised and virgin rubbers were studied, and the mechanical properties of revulcanised samples were compared with those of the virgin rubber. GPC results implied that the creation of a branched structure in the network was possible after devulcanisation. Revulcanisation of rubbers devulcanised under optimal conditions gave mechanical properties better than those of the virgin rubber. Blends of devulcanised and virgin rubbers showed the same tensile strength and modulus as the virgin rubber but higher elongation. 16 refs. USA

Accession no.659540 Item 271 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints. Cleveland, Oh., 21st-24th Oct.1997, Paper 78, pp.31. 012 INJECTION MOLDING OF A NATURAL RUBBER COMPOUND: SIMULATION AND EXPERIMENTAL STUDIES Isayev A I; Wan M Akron,University,Inst.of Polym.Engineering (ACS,Rubber Div.)

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References and Abstracts

Experimental and theoretical results were obtained for cavity filling in the injection moulding of an NR compound. The shear rate and temperature dependent viscosity function based on the modified Cross model was fitted to measured viscosity data. A non-isothermal vulcanisation model with non-isothermal induction time was fitted to the non-isothermal curing kinetic data obtained by DSC. These data were used in the simulation of the cavity filling and curing stages. Good agreement between experimental and theoretical results was found for pressure evolution during cavity filling and for evolution of state of cure in the mouldings. A substantial discrepancy was seen for pressure development in the nozzle, since the theoretical model did not take into account the extra pressure losses and flow induced crystallisation. 22 refs. USA

Accession no.659525 Item 272 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints. Cleveland, Oh., 21st-24th Oct.1997, Paper 71, pp.35. 012 CARBON-SILICA DUAL PHASE FILLER: A NEW GENERATION REINFORCING AGENT FOR RUBBER. III. ESCA AND IR CHARACTERIZATION OF CARBON-SILICA DUAL PHASE FILLERS Murphy L J; Wang M J; Mahmud K Cabot Corp. (ACS,Rubber Div.) The chemical nature of the carbon, oxygen and silicon in carbon-silica dual phase fillers was investigated by ESCA and IR spectroscopy. The silicon was consistent with that in silica, and the predominant carbon in the carbon phase was similar to that in carbon black. The fillers were composed of composite aggregates in which the silica phase was intimately distributed within the carbon phase. The observation of excess oxygen over the expected stoichiometric amount for silica was probably due to oxygen groups on the carbon phase. Analysis of the ESCA oxygen Auger lines in combination with acid treatments confirmed the presence of carbon phase oxygen groups. Quantitative ESCA combined with IR spectra of a filler after removal of the silica phase by hydrofluoric acid treatment suggested that the carbon phase contained more oxygen groups than conventional carbon black. 36 refs. USA

Accession no.659519 Item 273 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints.

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Cleveland, Oh., 21st-24th Oct.1997, Paper 70, pp.12. 012 SOLID-STATE NMR INVESTIGATIONS OF DIFFERENTIAL CURING AND MORPHOLOGY IN ISOBUTYLENE-BASED ELASTOMERS White J L; Dias A J; Gelan J Exxon Chemical Co.; Limburg,University (ACS,Rubber Div.) The crosslink density in cured brominated isobutyleneparamethylstyrene copolymers (BIMS) was measured by simple spin-echo relaxation time analyses. Direct observation of the tie chain in the network was possible through a combination of isotopically labelled curative and hydrogen-2 wideline NMR spectroscopy. These experiments revealed information about the optimum network density as a function of curative concentration. NMR imaging methods were used to directly probe spatial homogeneity in cured and compounded BIMS materials. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; USA; WESTERN EUROPE

Accession no.659518 Item 274 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints. Cleveland, Oh., 21st-24th Oct.1997, Paper 67, pp.13. 012 ANALYSIS OF TRANSMISSION SEALS BY ATOMIC FORCE MICROSCOPY Jacks J; Cornelis H; Kander R G Acadia Polymers Inc.; Virginia,Polytechnic Institute & State University (ACS,Rubber Div.) Tapping mode atomic force microscopy was used to study changes in surface hardness with driving time of fluoroelastomer seals used in automatic vehicle transmissions. The images obtained were correlated with the results of stress-strain and viscoelastic stress relaxation tests. 2 refs. USA

Accession no.659516 Item 275 IRC ’97. Conference proceedings. Kuala Lumpur, 6th-9th Oct.1997, p.171-3. 012 SURFACE TOPOGRAPHY AND ACTIVITY OF CARBON BLACK Raab H; Froehlich J; Goeritz D Regensburg,Universitat (Rubber Research Institute of Malaysia) By means of scanning probe microscopy (AFM, STM), the surface topography of carbon blacks is studied. The high resolution of the method results in a detailed structure of the surface and a model of the microstructure of the carbon black surface. In addition, the fractal dimension of the investigated carbon blacks is investigated by two

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References and Abstracts

methods: evaluation of the AFM and STM micrographs, and small angle x-ray scattering. 3 refs.

thermal stability decreases after storage of NR. The molecular structure and properties of NR are in a state of dynamic variation during accelerated storage. 7 refs.

EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

CHINA

Accession no.658880

Accession no.658337

Item 276 IRC ’97. Conference proceedings. Kuala Lumpur, 6th-9th Oct.1997, p.76-90. 012 VISUALISATION OF LEACHING EFFECT IN NR PREVULCANISED LATEX FILMS Amir-Hashim M Y; Cook S; Cudby P F; Farid A S; O’Brien M G Rubber Research Institute of Malaysia; Tun Abdul Razak Research Centre; North London,University (Rubber Research Institute of Malaysia)

Item 278 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints. Cleveland, Oh., 21st-24th Oct.1997, Paper 40, pp.10. 012 THERMAL AND SPECTROSCOPIC (VIBRATIONAL AND NUCLEAR MAGNETIC RESONANCE) CHARACTERIZATION OF ETHYLENE-PROPYLENE-DIENE (EPDM) ELASTOMERS Winter J M; Edmondson M S; Parikh D R; Mangold D J; Castille M J DuPont Dow Elastomers LLC (ACS,Rubber Div.)

Common methods of characterising network chain structure of NR vulcanisates are by using mathematical expressions to relate molecular weight (Mc) of chain segments between physical effective crosslinks to its elastic constants. A technique is developed to estimate NR network chain structure from micrographs obtained by transmission electron microscopy (TEM). Stained mesh sizes of different crosslinked dry rubber vulcanisates are shown to correlate well with the Mc determined by stress-strain measurement. This visualisation technique is applied to NR latex film to estimate its apparent physical effective crosslink density. Small changes in the concentration of crosslink density due to leaching, that may be significant but not detectable by the normal stress-strain method, can be calculated from TEM micrographs. 7 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; MALAYSIA; UK; WESTERN EUROPE

Accession no.658869 Item 277 IRC ’97. Conference proceedings. Kuala Lumpur, 6th-9th Oct.1997, p.569-74. 012 STUDY ON VARIATION OF STRUCTURE AND PROPERTIES OF NATURAL RUBBER DURING ACCELERATED STORAGE Li S-D; Yu H-P; Peng Z; Li P South China,Tropical Agricultural Product Processing Research Institute (Rubber Research Institute of Malaysia) The dynamic variations of molecular structure and properties of NR during accelerated storage are studied. The results show that, with the prolonged storage time, the average molecular weight and the gel content increases, the width index of molecular distribution decreases, gel size increases gradually, but the crosslink density of the gel fluctuates only within a narrow range. The initial Wallace plasticity increases, whereas the plasticity retention index decreases. Thermal analyses and IR spectroscopy show that the thermal degradation temperature drops, thermal degradation rate increases and

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The sequence distribution of EPM and EPDM samples prepared using vanadium/aluminium chloride and metallocene catalysts was studied by carbon-13 NMR and Fourier transform IR spectroscopy. The influence of sequence distribution on thermal properties was also investigated. 13 refs. USA

Accession no.658294 Item 279 Rubber Technology International 1997, p.129-30 PYROLYSIS-GCMS OF NATURAL AND SYNTHETIC RUBBERS CDS Analytical Inc. Carrying out effective molecular analysis on many rubber compounds can be a difficult operation with many routine analytical techniques failing to deliver effective results. Analytical pyrolysis, however, allows routine tools to be used to analyse polymers such as rubber. This technique permits the extension of routine tools to the analysis of polymers like rubbers by the controlled application of heat, producing molecular fragments which retain enough information about the original polymer to be instructive, yet small enough to be handled by gas chromatography. The pyrolysis of NR, polybutadiene and NR cured with carbon black is described. 3 refs. USA

Accession no.657656 Item 280 Acta Polymerica 48, No.9, Sept.1997, p.363-8 X-RAY INVESTIGATION OF THE STRUCTURE OF POLYURETHANE ELASTOMERS BASED ON 1,5-NAPHTHALENE DIISOCYANATE

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References and Abstracts

Androsch R; Blackwell J; Chvalun S N; Festel G; Eisenbach C D Case Western Reserve University; Stuttgart,University; Halle,Martin-Luther-Universitat; Moscow,Karpov Institute of Physical Chemistry The structure of the crystalline hard domains of polyurethane elastomers based on 1,5-naphthalene diisocyanate (NDI) was investigated by X-ray methods. The specimens were pressed films prepared from NDI and 1,4-butanediol (chain extender), with poly(oxytetramethylene) as the soft segments. 23 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; RUSSIA; USA; WESTERN EUROPE

Accession no.657623 Item 281 Polymer Bulletin 39, No.3, Sept.1997, p.317-24 SUPRAMOLECULAR ASSOCIATION OF ACID TERMINATED PDMS. I. SYNTHESIS AND CHARACTERISATION Abed S; Boileau S; Bouteiller L; Lacoudre N CNRS Benzoic acid terminated PDMS was synthesised by hydrosilylation of allyloxybenzylbenzoate with silicon hydride terminated precursors followed by deprotection. The oligomers were characterised by NMR, FTIR and by size exclusion chromatography in tetrahydrofuran. Mention is made of their suitability to study hydrogen bonding on macromolecular properties. 24 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.656865 Item 282 Rubber Chemistry and Technology 70, No.2, May-June 1997, p.202-10 STRAIN-CRYSTALLISATION OF GUAYULE AND HEVEA RUBBERS Choi I S; Roland C M Sachs/Freeman Associates; US,Naval Research Laboratory A comparison was made of the room temperature straincrystallisation of naturally-occurring polyisoprenes having varying non-rubber content. A variety of measurements were use to assess crystallisation including stress relaxation, optical birefringence, and the IR absorption spectrum. 62 refs. USA

Accession no.656174 Item 283 Journal of Applied Polymer Science 66, No.3, 17th Oct.1997, p.551-4

© Copyright 2001 Rapra Technology Limited

WOVEN FABRIC-ELASTOMER LAMINATE. I. THERMAL ANALYSIS OF CURE CHARACTERIZATION OF FLUOROCARBON ELASTOMER COATINGS Lee J H J; Jen-Cheng Chang; Hu A T; Jeng-Der Tsou Taiwan,National Tsing Hua University; Chung San,Institute of Science & Technology The curing of fluorocarbon elastomer coatings was analysed by DSC. The composition of the coatings included Viton GF (Du Pont), peroxide, triallyl isocyanurate, sublimed litharge, carbon black and solvent (MEK). Five different formulations of these compounds were examined. Kinetic studies indicated that the cure was completed in 3 min at an isothermal cure temp. of 180C. 9 refs. DU PONT TAIWAN

Accession no.656130 Item 284 Macromolecules 30, No.19, 22nd Sept.1997, p.5602-5 ARBORESCENT GRAFT POLYBUTADIENES Hempenius M A; Michelberger W; Moeller M Twente,University; Ulm,University Cascade-branched, ‘graft on graft’ polybutadienes, i.e. arborescent graft polymers, were prepared by hydrosilylation of polybutadiene vinyl groups with chlorodimethylsilane, followed by grafting with living polybutadiene chains. Repeated hydrosilylation-anionic grafting cycles led to a treelike outward growth, yielding well-defined, spherically shaped macromolecules. The molec.wt. of the materials increased dramatically with each grafting cycle, as polymer chains rather than small molecules were used as building blocks. The materials were characterised by means of GPC, static light scattering measurements and viscometry. 25 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; NETHERLANDS; WESTERN EUROPE

Accession no.654768 Item 285 Macromolecular Symposia Vol.119, July 1997, p.339-52 NMR INVESTIGATIONS ON DYNAMICAL ASPECTS OF AGEING PROCESSES IN ELASTOMERS Denner P; Walter B; Willing T Erfurt,Paedagogische Hochschule Proton spin relaxation measurements were used to investigate the effect of ageing on local and coherent segmental dynamics in cis-1,4-polybutadiene samples. The polymer chains in bulk polybutadiene were crosslinked by exposure to ionising radiation. The transmission of the hydrogen ion NMR signal from a

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References and Abstracts

liquid-like spin system response to a solid-like one is due to crosslinking and depends on the radiation dose. It is shown that the radiation yields changes in the constrained defect diffusion processes modelling the chain dynamics. Correlation time and memory time for the local and coherent segmental motion strongly depend on radiation dose. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.653747 Item 286 Macromolecular Symposia Vol.119, July 1997, p.119-28 ANALYSIS OF POLYMER MOBILITY BY FLUORESCENCE SPECTROSCOPY Klopffer M H; Bokobza L; Monnerie L ESPCI Fluorescence spectroscopy using an intramolecular excimer-forming probe was used to investigate chain mobility in various polybutadienes. The spectroscopic technique was completed by a rheological study carried out to identify the molecular parameters governing polymer dynamics. The temperature dependence of the correlation time of the probe motion could be fitted to a WLF equation which showed that the probe mobility reflected the Tg phenomenon of the host matrix. 16 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.653726 Item 287 Macromolecular Chemistry & Physics 198, No.9, Sept.1997, p.2667-88 SYNTHESIS OF BIOMEDICAL, FLUORESCENCE-LABELLED POLYESTERURETHANES FOR THE INVESTIGATION OF THEIR DEGRADATION Ciardelli G; Kojima K; Lendlein A; Neuenschwander P; Suter U W Zurich,Eidgenossische Technische Hochschule The synthesis and characterisation of fluorescencelabelled, phase segregating block polyester-urethanes based on the biocompatible and degradable materials poly-(R)-3-hydroxybutyric acid, poly-epsiloncaprolactone and epsilon-caprolactone-glycolide copolymer are described. Methods for introduction of fluorescence labelling are discussed. The block copolymers are shown to be promising materials for the investigation of the biocompatibility and degradation of the corresponding non-labelled materials by means of fluorescence-aided microscopic and spectroscopic techniques. 47 refs. SWITZERLAND; WESTERN EUROPE

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Item 288 Macromolecules 30, No.17, 25th Aug.1997, p.5175-7 DETERMINATION OF MOLECULAR WEIGHT AND COMPOSITIONAL HETEROGENEITY OF A GRAFT COPOLYMER BY A COMBINATION OF SIZE EXCLUSION CHROMATOGRAPHY(SEC) AND LOW-ANGLE LASER LIGHT SCATTERING(LALLS) Mrkvickova L Czech Republic,Academy of Sciences An efficient method for determination of MWD and average chemical heterogeneity parameters is described which involves a combination of SEC and on-line LALLS. Results obtained for PMMA grafted with polydimethylsiloxane, using toluene and THF as eluents, are presented and discussed. 18 refs. CZECH REPUBLIC

Accession no.653113 Item 289 Polymer 38, No.21, 1997, p.5261-6 FIRST SAMPLE OF SYNTHETIC RUBBER MADE BY WILLIAM TILDEN IN 1892 MODERN WORK REVEALS MYSTERY Bate D M; Lehrle R S; Place E J; Willis S L; Campbell D S; Hull C D Birmingham,University; Malaysian Rubber Producers’ Research Assn. A sample of synthetic rubber made in 1892 by Sir William Tilden at the Mason College of Science (precursor of the University of Birmingham), has come to light, and has been found to still possess remarkably good elastomeric properties. It is investigated by pyrolysis-g.c.-m.s. and by NMR spectroscopy in order to characterise its structure. 13 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.652540 Item 290 Kautchuk und Gummi Kunststoffe 50, Nos.7-8, July/Aug.1997, p.560-3 German SPATIALLY RESOLVED ANALYSIS OF CROSSLINK DENSITIES BY NMR Bluemich B; Bluemer P; Guthausen A; Fuelber C; Eidmann G; Savelsberg R NMR is a form of radio-frequency spectroscopy in strong magnetic fields. Different NMR parameters correspond to crosslink density, and carbon-black filled elastomers are transparent to radio frequency, so that NMR can be employed for determination of crosslink densities. Threedimensional spatial resolution can be generated based on the principles of magnetic resonance imaging known in

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References and Abstracts

EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

copolymers and the three monomer units (vinyl, trans and cis) in butadiene rubber polymers. PCA was compared with other currently-used methods. Cluster analysis was used to classify the SBRs and butadiene rubbers into groups. 25 refs.

Accession no.651449

USA

medical diagnostics, or a novel sonde can be positioned on the object, by which crosslink densities can be determined locally with limited depth resolution. 19 refs.

Accession no.647716 Item 291 Analytical Chemistry 69, No.18, 15th Sept.1997, p.3791-5 COMPOSITION AND MICROSTRUCTURE OF ACRYLONITRILE-BUTADIENE COPOLYMERS BY PYROLYSIS-PHOTOIONISATION MASS SPECTROMETRY Zoller D L; Johnston M V Delaware,University The composition and microstructure of acrylonitrilebutadiene copolymers ranging from 19 to 51 wt.% acrylonitrile are determined by pyrolysis-photoionisation mass spectrometry. The high molecular weight samples chosen for this study (Mw greater than 100 000) are relatively insoluble and therefore difficult or impossible to quantitatively characterise by NMR. A simple model based upon the average number of acrylonitrile units in a group of oligomers having the same total number of monomers but variable amounts of acrylonitrile and butadiene is found to give an accurate and precise determination of the copolymer composition. In addition, Bernoullian and first-order Markovian models were used to interpret the mass spectral data. Although the copolymer compositions calculated from each model agreed quantitatively with the reported compositions, the Markovian model gives slightly more precise fits to the mass spectra. Number-average sequence lengths are also determined from the Markovian model. The acrylonitrile sequence lengths determined by pyrolysis-photoionisation are larger than those reported previously for other copolymer samples. It is not known whether these differences reflect differences in the samples analysed or artefacts of the analytical techniques. 25 refs. USA

Accession no.651434 Item 292 Applied Spectroscopy 51, No.6, June 1997, p.889-97 USE OF CARBON-13 NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY AND PRINCIPAL COMPONENT ANALYSIS(PCA) FOR AUTOMATED ANALYSIS OF STYRENE/ BUTADIENE COPOLYMERS Walsh N G; Hardy J K; Rinaldi P L Akron,University PCA was used to determine percent composition of the four monomer units styrene, 1,2-butadiene (vinyl), trans1,4-butadiene (trans) and cis-1,4-butadiene (cis) is SBR

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Item 293 Polymer 38, No.16, 1997, p.4059-64 CURING CHARACTERISTICS AND MECHANICAL PROPERTIES OF SHORT OIL PALM FIBRE-REINFORCED RUBBER COMPOSITES Ismail H; Rosnah N; Rozman H D Universiti Sains Malaysia The curing characteristics and mechanical properties of oil palm fibre-reinforced natural rubber composites were studied. Modification of fibre surface and use of various bonding systems were found to increase the mechanical properties of oil palm fibre-reinforced NR composites. The presence of bonding agents in the composites was shown to prolong the curing time. Scorch and curing time, however, were independent of fibre loading and modification of fibre surface. SEM studies showed that the bonding between the fibre and rubber matrix was improved when the fibre was treated and used with various bonding agents. 18 refs. MALAYSIA

Accession no.647680 Item 294 Kobunshi Ronbunshu 54, No.5, 1997, p.359-61 Japanese IN-SITU ELECTRIC MEASUREMENT OF VULCANISATION PROCESS OF RUBBER Gondoh T; Eto S; Matsuoka Y; Toh M; Mori T; Okai D Kurume,College of Technology; Kyushu Rubber Co.Ltd. Progress of vulcanisation of NBR at 130-170C was followed by measurement of dielectric loss tangent (tan delta) and electric current (i). Both the tan delta and icure time curves showed a striking resemblance to the torque-cure time curve. That is, the time when the vulcanisation is complete (t100) and the apparent activation energy for vulcanisation reaction obtained from temperature dependence of t100 agreed with those from torque-cure time curves. 4 refs. JAPAN

Accession no.645101 Item 295 Journal of Applied Polymer Science

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References and Abstracts

65, No.1, 5th July 1997, p.187-90 POLYACRYLONITRILE DETERMINATION IN ACRYLONITRILE-BUTADIENE RUBBER Rodriguez A S; Policroniades R; Martinez-Quiroz E Mexico,National Institute of Nuclear Research

In addition, silicon-29 NMR spectra of metabolically active tissues (liver) showed the presence of chemically unchanged polysiloxanes and other silicon-containing compounds (silica), suggesting that these polymers were biodegradable. 45 refs.

Acrylonitrile content from NBR was studied combining vibrational spectroscopy and a nuclear technique. This non-destructive test is described. 14 refs.

USA

MEXICO

Item 298 151st ACS Rubber Division Meeting, Spring 1997, Conference Preprints. Anaheim, Ca., 6th-9th May 1997, Paper 56, pp.17. 012 HIGH-RESOLUTION NMR OF POLYBUTADIENE-CARBON BLACK INTERFACE Mansencal R; Haidar B; Delmotte L; Vidal A Institut de Chimie des Surfaces et Interfaces (ACS,Rubber Div.)

Accession no.639989 Item 296 151st ACS Rubber Division Meeting, Spring 1997, Conference Preprints. Anaheim, Ca., 6th-9th May 1997, Paper 96, pp.27. 012 INTRINSIC FLAWS IN NATURAL RUBBER Roland C M; Choi I S US,Naval Research Laboratory (ACS,Rubber Div.) A comparison was made of the room temperature strain crystallisation of naturally occurring cis-1,4polyisoprenes with varying non-rubber contents, i.e. NR grades of different purity, a deproteinised NR and a guayule rubber. Crystallisation was assessed by stress relaxation and optical birefringence measurements and IR spectroscopy. The results showed that the strain required to induce crystallisation was less for polymers having larger concentrations of impurities. Thus guayule rubber crystallised at lower strains than NR, and deproteinised NR required the highest strain to induce crystallisation. The propensity for strain crystallisation correlated with the relative failure properties of the rubbers. 62 refs. USA

Accession no.639073 Item 297 151st ACS Rubber Division Meeting, Spring 1997, Conference Preprints. Anaheim, Ca., 6th-9th May 1997, Paper 88, pp.24. 012 NMR OF TISSUES EXPOSED TO POLYSILOXANE GELS Garrido L Massachusetts General Hospital; Harvard Medical School (ACS,Rubber Div.) The migration of polysiloxanes from polysiloxane gel filled breast implants to local and distant sites in living systems was studied by NMR spectroscopy. Tissues from animals and humans exposed to the implants were studied in-vivo using proton NMR localised spectroscopy and invitro with proton and silicon-29 magic angle spinning NMR spectroscopy. The results showed that free polysiloxanes present in the implants migrated to surrounding tissues and distant organs such as the liver.

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Accession no.639065

Polymer-filler interactions in polybutadiene filled with carbon black were studied by solid state high-resolution NMR spectroscopy. Study of the relaxation behaviour of each line of the polymer spectra showed that the vinyl groups were more affected by the carbon black surface than the other species of the polymer chain. In the case of bound rubber, the vinyl groups were two times more immobilised than the methylene groups. Thus it could be concluded that the vinyl groups had a preferential interaction with the carbon black surface. 12 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; USA; WESTERN EUROPE

Accession no.639039 Item 299 Rubber World 216, No.2, May 1997, p.18-22 STANDARDISATION OF EPDM CHARACTERISATION TESTS FOR QC AND SPECIFICATION PURPOSES Noordermeer J W M DSM Elastomers Europe All EPDM manufacturing processes are highly proprietary and differ greatly between various suppliers. As a result, the various EPDM suppliers’ test methods for characterising the specific polymers have also evolved in different directions. Efforts have been made to standardise evaluation procedures for EPDM in collaboration with standardisation institutes such as ASTM, DIN and ISO. A working group was established which developed a set of “best practice” test methods for EPDM. The results of these activities are described in this article. 14 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.638595

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References and Abstracts

Item 300 Kautchuk und Gummi Kunststoffe 50, No.5, 1997, p.386-91 German ISOTHIOCYANATES FORMED DURING ACCELERATED VULCANISATION. I. THIURAM- AND DITHIO-CARBAMATEACCELERATORS Kretzschmar H-J; Weigel H Reaction products formed during accelerated vulcanisation were analysed by gas chromatography combined with mass spectrometry. The reduction of hazardous components of fumes by small changes to either the formulation or processing conditions are discussed. 6 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.637898 Item 301 Kautchuk und Gummi Kunststoffe 50, No.5, 1997, p.380-5 German DETERMINATION OF CARBONYL COMPOUNDS IN EMISSIONS FROM MANUFACTURE AND STORAGE OF RUBBER PRODUCTS Kuhn-Stoffers P; Giese U; Schuster R H; Wunsch G Activated carbon and silica gels, surface-modified with dinitrophenyl hydrazine, were examined in terms of their suitability for sampling aldehydes and ketones in vulcanisation fumes. The study demonstrates that the deriving reaction is preceded by an adsorption on the substrate material and that subsequent quantitative transformation to the hydrazone requires different reaction times depending on the reactivity of the carbonyl components. 22 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.637897 Item 302 China Synthetic Rubber Industry 20, No.3, 1997, p.186-9 Chinese APPLICATION OF FOURIER TRANSFORM INFRARED SPECTROMETER Jia Hongbing; Liu Shouping; Zhang Shiqi Nanjing,University of Science & Technology The literature on the use of a Fourier transform IR spectrometer for the study of characteristic chemical reactions and mechanochemical reactions of elastomers is reviewed. 32 refs. CHINA

Accession no.636611

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Item 303 151st ACS Rubber Division Meeting, Spring 1997, Conference Preprints. Anaheim, Ca., 6th-9th May 1997, Paper 26, pp.24. 012 EFFECTS OF HEATING AND THE COOLING RATE ON THE STRUCTURE OF CARBON BLACK PARTICLES Zerda T W; Xu W; Yang H; Gerspacher M Texas,Christian University; Richardson S.,Carbon Co. (ACS,Rubber Div.) The effects of heating and quenching on the structure of N299 and N660 carbon black particles were studied by Raman spectroscopy, X-ray diffraction and the BET technique. The samples were kept at 2500K for various lengths of time and then cooled at different rates. The size of crystallites and the surface roughness of the particles were determined for the different treatment schedules. The fractal dimension decreased from 2.2 for untreated samples to 2.0 for samples heat treated to 1000C. Cooling rates did not affect surface roughness, but rapid cooling reduced crystallite sizes. It was postulated that the surface of the carbon particles was composed of crystallites and amorphous carbon, with the amount of the latter depending on the thermal treatment. The role of amorphous carbon in determining the reinforcing properties of carbon blacks in tyres was examined by testing the static stress-strain and low strain dynamic properties of SBR mixed with untreated, slowly cooled and rapidly cooled carbon blacks. 19 refs. USA

Accession no.636037 Item 304 Journal of Materials Science 32, No.10, 15th May 1997, p.2617-21 FOURIER TRANSFORM INFRARED ANALYSIS OF POLYESTER-URETHANES AT LOW TEMPERATURE IN-SITU BY USING A NEWLY CONSTRUCTED LIQUID NITROGEN COOLED SAMPLE STAGE Rehman I; Barnardo C; Smith R London,University,Queen Mary & Westfield College The design and use of equipment for cooling samples for in-situ FTIR spectroscopic studies are described. It is shown that, using liquid nitrogen as the cooling medium, a working sample temp. of -165C can be achieved. The combination of the cooling stage and FTIR spectroscopy permits study of the hydrogen bonding in PUs at very low temps. in-situ. Experimental results in the N-H and carbonyl absorption regions as a function of temp. are compared. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.635235

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References and Abstracts

Item 305 China Synthetic Rubber Industry 20, No.2, 1997, p.112-4 Chinese APPLICATION OF MODIFIED BENTONITE IN STYRENE BUTADIENE RUBBER Shuwen P; Zhenming Z; Chunxian J Jilin Chemical Industry Corp. The effect of particle size on the mechanical properties of vulcanised SBR is discussed by filling with organic amine modified bentonite. The result of using modified bentonite as a filler is compared with the use of calcium carbonate. The compatibility of modified bentonite with SBR is compared with that of silica and carbon black. The structure change of modified bentonite is analysed by X-ray and IR analysis. 2 refs. CHINA

Accession no.632004 Item 306 Analytical Chemistry 69, No.7, 1st April 1997, p.1267-72 DETECTION AND CHARACTERIZATION OF POLYDIMETHYLSILOXANES IN BIOLOGICAL TISSUES BY GAS CHROMATOGRAPHY(GC)/ ATOMIC EMISSION DETECTION(AED) AND GC/MASS SPECTROMETRY(MS) Kala S V; Lykissa E D; Lebovitz R M Baylor College of Medicine A sensitive method was developed for detection, characterisation and quantification of low molec.wt. silicones using GC/AED and G C/MS. Using this approach, twelve distinct silicon-containing peaks were detected in polydimethylsiloxane oil by GC/AED, and GC/MS analysis was used to identify some of the abundant peaks by MS spectral matching. The described methodology was shown to have the potential to allow the measurement of less than 1 micro g of silicone/g of biological tissue. 8 refs. USA

Accession no.631642 Item 307 Kobunshi Ronbunshu 54, No.2, 1997, p.108-14 Japanese STRUCTURAL CHARACTERIZATION BY PYROLYSIS GAS CHROMATOGRAPHY OF ETHYLENE-PROPYLENE-DIENE RUBBERS CURED WITH SULPHUR/THIAZOLE ACCELERATOR Okumoto T; Yamada T; Tsuge S; Ohtani H Toyota Technical Institute; Toyoda Gosei Co.Ltd.; Nagoya,University EPDM rubbers cured with sulphur and accelerators were characterised by high resolution pyrolysis gas

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chromatography with both a flame ionisation detector and a sulphur-selective flame photometric detector. For curing with sulphur and 2-mercaptobenzothiazole accelerator, two types of sulphur-containing products, such as cyclopentathiophene and benzothiazole, were typically observed in the pyrogram. The former was supposed to be formed from sulphur bridges to ethylidene norbornene residue in the polymer chain through cyclisation, while the latter was considered to be derived from the pendant accelerator residue. The vulcanisation process for EPDM rubber was examined on the basis of the relationships between the peak intensities of the characteristic products and cure time. 18 refs. JAPAN

Accession no.631060 Item 308 Kobunshi Ronbunshu 54, No.1, 1997, p.10-14 Japanese INFLUENCE OF CROSSLINK STRUCTURE ON VISCOELASTICITY OF POLYBUTADIENE LATEX FILMS Ikawa K; Sakano H; Tamai S Sumika A & L Inc. The dynamic viscoelastic properties of cast films of polybutadiene latex, in which the gel content was controlled by terminating the reaction at a certain conversion or by increasing the amount of chain transfer agent, were measured in order to study the crosslink structure. The Tg and tan delta peak at Tg were independent of the gel content, i.e. the degree of crosslinking, but dependent on the molec.wt. of the main chains. The Tg of samples prepared by the method involving increasing the amount of chain transfer agent was slightly higher than that of the samples prepared by terminating the reaction, which could be ascribed to the difference of the mobility of local chains. At a higher temp., E starred and tan delta were dependent on both the gel content and the amount of chain transfer agent. As the time scale of samples was in the rubbery stage to flow region at 0C, viscoelastic properties were strongly influenced by the molec.wt. of sol-like portions, which existed at the boundary between the microgel particles. 15 refs. JAPAN

Accession no.631019 Item 309 Kautchuk und Gummi Kunststoffe 50, No.1, Jan.1997, p.6-11 STRUCTURAL CHARACTERIZATION OF NATURAL RUBBER Tanaka Y; Kawahara S; Tangpakdee J Tokyo,University of Agriculture & Technology

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References and Abstracts

NR from Hevea brasiliensis was shown to be a polyisoprene comprising two trans-isoprene units and a long sequence of cis-isoprene units. The structural evidence showed that the rubber formation started from C15-trans-trans-farnesyl diphosphate(FDP), followed by biochemical modification at the dimethylallyl group, or started from a derivative of FDP. The bimodal MWD of NR was presumed to be due to biodynamic origin and not to branching only. A deproteinisation process of NR reduced the gel content to 1 to 2%, but did not affect the green strength nor other vulcanisate properties. 29 refs. JAPAN

Accession no.630987 Item 310 China Rubber Industry 44, No.2, 1997, p.113-5 Chinese INFRARED SPECTROSCOPIC ANALYSIS OF SBS-ACRYLIC GRAFT COPOLYMER Ye Xiaowei; Zhou Xiaohui 2 refs. CHINA

Accession no.626124 Item 311 Polymer 38, No.5, March 1997, p.1011-6 STUDY OF THE POLYMER MORPHOLOGY IN A POLY(ESTER-URETHANE) ELASTOMER BY SOLID STATE HYDROGEN ION NMR SPECTROSCOPY Clayden N J; Nijs C L; Eeckhaut G J East Anglia,University; ICI Polyurethanes The variation in the mobile fraction seen in the hydrogen ion NMR free induction decay was analysed using the Thomson-Gibbs equation to give the hard block lamellae thickness distribution in a poly(ester-urethane) elastomer. Attempts to use hydrogen ion spin diffusion to fix the absolute distance scale were unsuccessful since the results indicated a heterogeneity with not all of the soft segments contributing to a simple two-phase hard/soft domain morphology. 17 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.625735 Item 312 Polymer Bulletin 38, No.3, March 1997, p.333-7 (CARBON-13)SPIN LATTICE RELAXATION IN ROTATING FRAME BEHAVIOUR OF SOME ELASTOMERS Nelliappan V; El-Aasser M S; Klein A; Daniels E S; Roberts J E

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Lehigh University Temperature dependences of NMR relaxation behaviour of poly(butyl acrylate), cis-polyisoprene, polychloroprene, and cis-polybutadiene were studied. The temperature dependence of the relaxation time for each elastomer followed the WLF equation. 10 refs. USA

Accession no.625713 Item 313 Journal of Applied Polymer Science 63, No.8, 22nd Feb.1997, p.1077-89 SYNTHESIS AND CHARACTERISATION OF PENDENT HYDROXY FLUOROESTERS OF SECONDARY HIGH MOLECULAR WEIGHT GUAYULE RUBBER Thames S F; Gupta S Southern Mississippi,University The epoxidation of secondary high molecular weight guayule rubber and subsequent ring opening with fluoroacids to give hydroxyfluoroesters is reported. Structural characterisation was performed with Fourier transform IR spectroscopy, hydrogen-1, carbon-13 and fluorine-19 NMR spectroscopy and DSC, and the per cent epoxidation was quantitatively determined by hydrogen1 NMR spectroscopy. The Tg values of the fluorinated polymers increased with increasing fluoroacid content. However, reactions with longer chain highly fluorinated acids lowered the Tg. PU coating compositions were prepared by blending the trifluoroacetic acid ester with a polyester resin and a polyisocyanate. 35 refs. USA

Accession no.624395 Item 314 Polymer Bulletin 38, No.1, Jan.1997, p.101-8 SPATIALLY RESOLVED AND INTEGRAL NMR INVESTIGATION OF THE AGEING PROCESS OF CARBON BLACK FILLED NATURAL RUBBER Knorgen M; Heuert U; Schneider H; Barth P; Kuhn W Halle,Universitat; Fraunhofer-Institut fuer Biomedizinische Technik A complex ageing regime takes place during thermal ageing of NR. A series of differently aged carbon black filled NR was investigated by parameter-selective magnetic resonance imaging, and some statements are given about the ageing regime in the body and in the surface layer. An air and a nitrogen aged sample series was compared by spatially resolved and integral hydrogen ion NMR to determine the role of the oxygen. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.618982

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References and Abstracts

Item 315 International Seminar on Elastomers. Applied Polymer Symposium proceedings. Akron, Oh., 14th-16th July 1993, p.5-14. 012 STRUCTURAL CHARACTERISTICS OF NATURAL RUBBER - ROLE OF ESTER GROUPS Aik-Hwee E; Ejiri S; Kawahara S; Tanaka Y Tokyo,University of Agriculture & Technology Edited by: White J L; Inoue T Applied Polymer Symposium 53 Long-chain fatty acid ester groups were found to remain in Hevea rubber to the extent of 5-8 mmol/kg even after deproteinisation of latex and reprecipitation or acetone extraction of rubber. The quantity of ester groups was 1.5-2.5 per chain for fractionated samples which was comparable to that of trans isoprene units at the initiating terminal of polymer chain. Ester groups were removed from rubber by transesterification with sodium methoxide in toluene and the isolated methyl esters were found to be composed of mainly saturated C16-18 fatty acids. Rubber purified by acetone extraction showed a significant decrease in the rate of crystallisation at -25 deg.C, while the transesterified rubber exhibited crystallisability comparable to untreated rubber. Bimodal molecular weight distribution became apparent after transesterification and Mn was reduced to about one-third. A significant decrease of green strength was observed for transesterified rubber, while highly deproteinised rubber showed a similar green strength as untreated rubber. The number average molecular weight of fractionated deproteinised NR was determined by osmometry and 13C-NMR assuming that two trans isoprene units are present at the initiating terminal. High molecular weight fractions showed much higher Mn value than that determined by 13C-NMR. This discrepancy was satisfactorily interpreted by assuming branched structure consisting of 5 to 2 linear chains each of which contains two trans isoprene units at the terminal. 13 refs. JAPAN

and relies on diffusive transport as the principal mechanism of separation. An open channel geometry minimises shear effects, making it possible to separate fragile, high molecular weight polymers, while the absence of a stationary phase means that adsorption effects can be ignored. It is possible to calculate molecular weight distributions of a polymer eluting from a THFFF channel using calibration techniques similar to those used in size exclusion chromatography. However, the addition of multiangle laser light scattering (MALLS) to THFFF has allowed absolute molar mass and size distributions to be obtained without the need for calibration, standards or assumptions. Complexes of polymer, micro-gel and macro-gel can be studied in a single run without the need for filtration. By combining all the information derived from THFFF/ MALLS, the real molecular weight distribution, including levels of branching, can be determined. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.610152 Item 317 European Rubber Journal 178, No.9, Oct.1996, p.30-1 NEW MOL WT TEST REVEALS ALL Fulton S; Thorpe W; White R Malaysian Rubber Producers’ Research Assn.; Optokem Instruments Ltd. This article introduces a novel way of assessing molecular weight in elastomers, which seems likely to give a more complete picture of the material than previous determinations. The test is a combination of thermal field flow fractionation (ThFFF) and multi-angle laser light scattering (MALLS), and has allowed absolute molar mass and size distribution to be obtained without the need for calibration, standards or assumptions. MALAYSIA

Accession no.603741

Accession no.611248 Item 316 IRC ’96. International Rubber Conference. Conference proceedings. Manchester, 17th-21st June 1996, poster 8. 012 USE OF THERMAL FIELD FLOW FRACTIONATION AND MULTI-ANGLE LASER LIGHT SCATTERING TO DETERMINE THE REAL MOLECULAR WEIGHT DISTRIBUTION OF ELASTOMERS Fulton W S; Thrope W M H; White R J Malaysian Rubber Producers’ Research Assn.; Optokem Instruments Ltd. (Institute of Materials) Thermal Field-Flow Fractionation (THFFF) is a relatively new technique for separating and characterising polymers

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Item 318 Analytical Chemistry 67, No.12, 15th June 1995, p.97R-126R ANALYSIS OF SYNTHETIC POLYMERS AND RUBBERS Smith C G; Smith P B; Pasztor A J; McKelvy M L; Meunier D M; Froelicher S W Dow Chemical USA A detailed review is presented of the literature on techniques for characterisation and analysis of rubbers and synthetic polymers, copolymers and blends. Chromatographic techniques such as gas chromatography, inverse gas chromatography, pyrolysis gas chromatography, and liquid chromatography, including size exclusion chromatography, are included, together with references to mass spectrometry, IR, Raman and NMR spectroscopies, and thermal techniques such as TGA and DSC. Applications include structure

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References and Abstracts

determination, separation and quantification of residual monomers and additives, determination of molec.wt. and study of degradation mechanisms and other thermal properties of synthetic polymers and rubbers. 1009 refs. USA

Accession no.556196 Item 319 Shawbury, 1994, pp.105. LS.150. 12ins. 11/1/95. 12392171T RUBBER FUME : INGREDIENT/EMISSION RELATIONSHIPS Willoughby B Rapra Technology Ltd. This comprehensive review covers the Rapra Vulcanisation Fume Project - a unique study analysing cure volatiles from a suite of formulations using a common pool of ingredients. The experiments were conducted under strict laboratory control and the analytical findings are presented, discussed, and where appropriate compared with on-site data. This publication may be purchased from Rapra Technology Ltd. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.539295 Item 320 Materials World 1, No.10, Oct.1994, p.532-3 PROBING THE SURFACE TO IMPROVE PERFORMANCE Harrison K; Hazell L B CSMA Ltd. Information is presented in some detail on techniques in surface analysis. The performance characteristics of five methods of analysis are given in tabular form. Those methods are:- X-ray photoelectron spectroscopy (XPS), auger electron spectroscopy (AES), static/dynamic secondary ion mass spectrometry (SIMS), and laser ion mass analysis (LIMA). The importance of monolayer chemistry in a wide range of applications is discussed. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.538680 Item 321 IRC ’93/144th Meeting, Fall 1993. Conference Proceedings. Orlando, Fl., 26th-29th Oct.1993, Paper 105, pp.28. 012 APPLICATIONS OF RAMAN SPECTROSCOPY TO THE ANALYSIS OF NATURAL RUBBER Hendra P J; Jackson K D O Southampton,University; Malaysian Rubber Producers’ Research Assn. (ACS,Rubber Div.)

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Applications of Fourier transform Raman spectroscopy to the analysis of NR are described. Of particular interest is the observation of main chain modifications during vulcanisation and the ability to observe the conversion of insoluble to soluble sulphur under conditions appropriate to compounding and vulcanisation. The influence of crystallisation, both temperature and strain induced, on the Raman spectrum of NR is also demonstrated. 9 refs. EUROPEAN COMMUNITY; UK; USA; WESTERN EUROPE

Accession no.505679 Item 322 Shawbury, Rapra Technology ltd., 1993, pp.122. 12ins. 22/11/93. Rapra Review Rept.No.68. Vol.6, No.8, 1993. 9111T CURE ASSESSMENT BY PHYSICAL AND CHEMICAL TECHNIQUES Willoughby B G Rapra Technology Ltd. Edited by: Dolbey R Rapra Review Report No.68 Physical and chemical monitoring methods used to evaluate the state of curing are described and critically evaluated. Comments on both practical and theoretical aspects of cure monitoring are included and the process of cure itself is considered. 510 refs. This item is available only by purchase from Rapra Technology Ltd. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.501040 Item 323 Kautchuk und Gummi Kunststoffe 45, No.11, Nov.1992, p.910-7 FOURIER TRANSFORM RAMAN SPECTROSCOPY IN THE ANALYSIS OF ELASTOMERS. PART 2. SYNTHETIC RUBBERS Hendra P J; Jones C H; Wallen P J; Ellis G; Kip B J; van Duin M; Jackson K D O; Loadman M J R Southampton,University; Madrid,Instituto de Ciencia y Tec.de Polim.; DSM Research BV; Malaysian Rubber Producers’ Research Assn. Fourier Transform (FT)-Raman spectroscopy is applied to the study of various commercially-available raw synthetic elastic materials with special reference to polybutadiene and its commercial copolymers. The FTRaman spectra are compared with conventional Raman spectra, IR spectra and FT-NMR spectra; some band assignments are given. FT-Raman spectroscopy can be used to identify raw polymers rapidly and it is shown that in the case of homopolymers and copolymers of butadiene rubbers, isomeric structure can also be found. 24 refs. EUROPEAN COMMUNITY; NETHERLANDS; SPAIN; UK; WESTERN EUROPE

Accession no.480505

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References and Abstracts

Item 324 Rubbercon 92 - A Vision for Europe.Conference Proceedings. Brighton,15th-19th June 1992,p.281-7. 012 STUDY OF BRASS-RUBBER ADHESION IN TYRES - RESULTS OBTAINED BY SEVERAL EXPERIMENTAL TECHNIQUES USED TO STUDY THE SURFACE OF TYRE CORD Lehrle R S; Niderost K J Birmingham,University; SP Tyres (UK) Ltd. (PRI)

Item 326 Angewandte Makromolekulare Chemie Vol.202/203,Dec.1992,p.283-93 DETERMINATION OF CROSSLINK DENSITIES OF CARBON BLACK-FILLED NATURAL RUBBER SULPHUR VULCANISATES BY CARBON-13 NMR MAGIC ANGLE SPINNING SPECTROSCOPY AND PROTON NMR TRANSVERSAL RELAXATION Hoffmann U; Gronski W; Simon G; Wutzler A Merseburg,Technische Hochschule

Of the various techniques available for studying brassrubber adhesion, scanning electron microscopy (SEM) with X-ray microanalysis (XRMA), Auger electron spectroscopy (AES) and laser ionisation mass analysis (LIMA) are the principal ones used in this work. Results obtained with brass plated tyre cords, some having a phosphate treatment, which are available for tyre manufacture indicate that the surface can be very irregular. Furthermore, the surface composition of the brass is found to be very different from the bulk composition. 7 refs.

The above NMR spectroscopic methods were applied to carbon black-filled NR vulcanisates in order to determine the chemical crosslink density. The two methods were shown to give corresponding results. Addition of carbon black led to a decrease of crosslink density with increasing filler content, the effect being more marked at higher sulphur contents. 24 refs. (GDCh Fachgruppe ‘Makromolekulare Chemie’ on Rubber-Elastic Polymer Systems,Bad Nauheim,Germany,March 1992) EUROPEAN COMMUNITY; GERMANY; WESTERN EUROPE

EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.467846

Accession no.471640 Item 325 Rubber Chemistry and Technology 65,No.5,Nov./Dec.1992,p.890-907 FILLER-ELASTOMER INTERACTIONS. VI. CHARACTERISATION OF CARBON BLACKS BY INVERSE GAS CHROMATOGRAPHY AT FINITE CONCENTRATION Wang M J; Wolff S Degussa AG Carbon blacks ranging from N110 to N990 were characterised by means of inverse gas chromatography at finite concentration. The isotherms, net heat and spreading pressures for benzene and cyclohexane adsorption suggested a general trend of increasing surface activity with increases in specific surface area. This was in good agreement with surface energy measurements reported previously. The energy distribution function of adsorption showed that while the concentrations of low energy sites were comparable for most of the carbon blacks, differences existed with regard to high energy sites. These indicated that small particle size blacks possessed a greater number of high energy centres. The graphitisation of carbon blacks resulted in a significant reduction in their adsorption capacity and narrowed the energy distribution of their surfaces. It was concluded that high energy sites played an important role in the determination of the surface energies and reinforcing ability of carbon blacks. 25 refs. EUROPEAN COMMUNITY; GERMANY; WESTERN EUROPE

Accession no.467852

Item 327 Rubber Chemistry and Technology 65,No.1,March/April 1992,p.63-77 STRUCTURE AND DENSITY OF CROSSLINKS IN NR VULCANISATES. COMBINED ANALYSIS BY NMR SPECTROSCOPY, MECHANICAL MEASUREMENTS AND RUBBER-ELASTIC THEORY Gronski W;Hoffmann U;Simon G;Wutzler A;Straube E FREIBURG,UNIVERSITY; MERSEBURG,UNIVERSITY Crosslink density in sulphur-accelerated NR vulcanisates was quantitatively determined by means of carbon-13 NMR magic angle spinning solid-state spectroscopy and proton NMR measurements. It was found that carbon-13 NMR spectroscopy could distinguish between monosulphidic crosslinks and polysulphidic structures. The chemical crosslink density determined by an approach based on the tube concept was in approximate agreement with the NMR results. (ACS,Toronto,Canada, 21-24 May 1991). 21 refs. GERMANY

Accession no.456730 Item 328 Rubber Chemistry and Technology 64,No.5,Nov/Dec.1991,p.708-13 CHARACTERISATION OF VULCANISED EPDM RUBBERS BY HIGH-RESOLUTION PYROLYSIS GAS CHROMATOGRAPHY (HRPGC) Yamada T;Okumoto T;Ohtani H;Tsuge S NAGOYA,UNIVERSITY; TOYODA GOSEI CO.LTD. Vulcanised ethylene-propylene-ethylidenenorbornene rubbers cured with two types of vulcanising agents

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References and Abstracts

(sulphur and dicumyl peroxide) were investigated using HRPGS. Characteristic pyrolysis products formed at 650C were separated by the high-resolution capillary column and the resulting pyrograms interpreted in terms of ethylidene norbornene (ENB) content in the vulcanisates. The thermal degradation behaviour of the ENB units in the rubber was also investigated. JAPAN

Accession no.448611 Item 329 International Rubber Conference.Summaries. Essen,24th-27th June 1991,p.311-4. 012 STRUCTURE AND DENSITY OF CROSSLINKS IN SULPHUR VULCANISATES - A COMBINED ANALYSIS BY NMR SPECTROSCOPY AND MECHANICAL MEASUREMENTS Gronski W;Hoffmann U;Freund B;Wolff S FREIBURG,UNIVERSITY (Deutsche Kautschuk Ges.) 12 refs. GERMANY

Accession no.435664 Item 330 Applied Spectroscopy 45,No.5,June 1991,p.808-18 NONINVASIVE POLYMER REACTION MONITORING BY IR EMISSION SPECTROSCOPY WITH MULTIVARIATE STATISTICAL MODELLING Pell R J;Callis J B;Kowalski B R WASHINGTON,UNIVERSITY The curing of a commercial paint product was monitored by IR absorption and emission spectroscopy. Analysis of the principal components of the absorption data indicated that three factors were needed to explain the observed spectral/ temporal variance; this is discussed in terms of changes in the physical state of the reaction mixture. 38 refs. USA

Accession no.428815 Item 331 Rubber Chemistry and Technology 64,No.1,March/April 1991,p.40-56 SOLID-STATE CARBON 13 NMR STUDIES OF VULCANISED ELASTOMERS. VIII. ACCELERATED SULPHUR-VULCANISED BUTYL RUBBER AT 75.5 MHZ Krejsa M R;Koenig J L CASE WESTERN RESERVE UNIVERSITY 57 refs. USA

Accession no.424316

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Item 332 Fall Meeting(134th),1988. Cincinnati,Oh.,18-21st Oct.1988,Paper 26,pp.50. 012 SURFACE CHARACTERISATION OF RUBBER BY SECONDARY ION MASS SPECTROMETRY van Ooij W J;Nahmias M COLORADO,SCHOOL OF MINES; PIRELLI SPA (ACS,Rubber Div.) The results are reported of some preliminary studies of rubber molecules and surfaces using static secondary ion mass spectrometry (SIMS). The capability of SIMS to identify certain features in the structure of aliphatic hydrocarbons and the possibility of investigating sulphur crosslinks therewith are also examined. Materials analysed included LDPE, HDPE, PP, cis-polybutadiene, cis-polyisoprene, NR, EPDM, SBR, butyl rubber, SBS and SAN. 21 refs. ITALY; USA; EUROPEAN COMMUNITY

Accession no.389441 Item 333 Spring Meeting(133rd),1988. Dallas,Tx,19-22nd April 1988,Paper 7,pp.23. 012 CARBON BLACK CHARACTERISATION AND APPLICATION TO STUDY OF POLYMER/ FILLER INTERACTION Gerspacher M;Lansinger C M GOODYEAR TIRE & RUBBER CO. (ACS,Rubber Div.) It is demonstrated that carbon black characteristics based on crystallographic considerations as well as aggregate size measurements might be capable of better defining the filler with respect to its reinforcing ability (in terms of low strain elastic modulus) in rubber compounds. In addition, such an approach could ultimately lead to a more scientific understanding of the interaction between carbon black and polymers and the effect of this interaction on compound end-use properties. 27 refs. USA

Accession no.386435 Item 334 132nd Meeting,Fall 1987.Preprints. Cleveland,Ohio,Oct.6-9,1987,Paper 86 TANDEM MASS SPECTROMETRY (MS/MS) FOR ANALYSIS OF ADDITIVES IN A RUBBER VULCANISATE Lattimer R P GOODRICH B.F.,RES.& DEV.CENTER (ACS,Rubber Div.) The direct tandem mass spectrometric analysis (MS/MS) of a NR vulcanisate is described and the use of daughter ion, parent ion and neutral loss MS/MS scans to reduce chemical noise and provide added specificity for component identification demonstrated. The rubber was

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References and Abstracts

heated in the direct probe (50 to 300C) to volatilise the organic additives for analysis and ionisation was by electron impact. 22 refs. USA

Accession no.344632 Item 335 Muanyag es Gumi 21,No.11,Nov.1984,p.340-5 Hungarian CHEMICAL ANALYSIS OF RUBBER MIXES Ivicz Boros M;Spacsek K A complete system of analysis for rubber mixes of unknown composition is described. Test methods are surveyed and a method is given for calculation of suitable formulations. 9 refs. Articles from this journal can be requested for translation by subscribers to the RAPRA produced International Polymer Science and Technology. HUNGARY

Accession no.266669 Item 336 Shawbury, 1983, pp.25. 12ins. 2copies. 5/12/83. N.PUBL. 91T CONTRIBUTIONS OF THERMOGRAVIMETRY TO THE ANALYSIS OF NITRILE, FLUOROCARBON AND CHLOROPRENE RUBBERS Sidwell J A RUBBER & PLASTICS RESEARCH ASSN.OF GT.BRITAIN Rubber & Plastics RA.Members Rept.086 This report details the findings of an experimental study undertaken to evaluate the potential of the technique of thermogravimetry for the analysis of complex formulations of butadiene-acrylonitrile, fluorocarbon (Viton) and chloroprene rubber. Included in the formulations studied were various monomeric and polymeric additives, different particle size and structured carbon blacks and a selection of inorganic fillers. 6 refs. UK

Accession no.246905 Item 337 123rd Meeting - Spring. Toronto,1983,May 9-13,Paper 67,pp.30. 012 VULCANISATION STUDIES OF ELASTOMERS USING SOLID STATE CARBON-13 NMR Patterson D J;Koenig J L;Shelton J R (ACS,Rubber Div.) A study was made of NR and cis-polybutadiene samples crosslinked with dicumyl peroxide using solid state carbon13 NMR and Fourier transform infrared spectroscopy. Cistrans conversion in the main chain backbone by allylic shift of the double bond was observed as well as quaternary

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carbon formation for the NR. Four structurally different methyl resonances were also observed in the spectra of crosslinked NR. All resonance-linewidths were found to increase with degree of cure, the increases being attributed to C-H dipolar interaction. From an analysis of the data obtained, models are proposed for the crosslinked NR and BR networks. 57 refs. USA

Accession no.239726 Item 338 Journal of Applied Polymer Science 27,No.7,July 1982,p.2527-37 STUDY OF SULPHUR BRIDGES IN FILLED NATURAL RUBBER VULCANISATES BY PYROLYSIS GAS CHROMATOGRAPHY WITH FLAME-PHOTOMETRIC DETECTION Andersson E M; Ericsson I; Trojer L A study was made of sulphur bridges in carbon black filled NR vulcanisates cured with either sulphur/N-cyclohexyl2-benzothiazolesulphenamide or tetramethylthiuram disulphide using a sulphur-selective flame-photometric detector. It was found that the main pyrolysis products were C52 and thiophenes and that the yields of the pyrolysis products were considerably different from the two types opf rubber and varied with cure time. 25 refs. Accession no.216148 Item 339 Weinheim, Verlag Chemie GmbH, 1981, pp.XV,687. 12ins. 22/3/82. R.ROOM. 91T ATLAS OF POLYMER AND PLASTICS ANALYSIS. VOL.3....ADDITIVES AND PROCESSING AIDS: SPECTRA AND METHODS OF IDENTIFICATION. 2ND REV.EDN. Scholl F The spectroscopic and chromatographic data that are required for the identification of plastics additives and processing aids are presented. Over 1300 IR spectra and 60 UV spectra are included. The functions and compositions as well as the physical and chemical methods of identification of the following materials are discussed: plasticisers, fillers, pigments, antioxidants, UV stabilisers, optical brighteners, antistatic agents, biostabilisers, flame retardants, lubricants, accelerators, hardeners and blowing agents. 608 refs. Accession no.211056 Item 340 ed. Barking, Applied Science Publishers Ltd., 1982, pp.xi,262. LS.18. 9ins. 4copies. 7/12/81. R.ROOM. 6121 POLYMER LATICES AND THEIR APPLICATIONS Calvert K O Accession no.205242

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References and Abstracts

Item 341 Nippon Gomu Kyokaishi 54,No.11,1981,p.673-81 Japanese CHEMICAL ANALYSIS OF RUBBER PRODUCTS Yoda R 96 refs. Accession no.203093 Item 342 Developments in Polymer Degradation-3; ed.by N.Grassie Barking, Applied Science Publishers Ltd.,1981, p.27-61. R.ROOM.93 CALORIMETRIC STUDIES OF RUBBER VULCANISATION AND VULCANISATES Brazier D W Studies using DSC and differential calorimetry to characterise the cure process, the nature of the product and the subsequent ageing processes are described. Enthalpy changes accompanying chemical events in the system are monitored either as a function of temp. or time. The current state of the art in the interpretation of the enthalpy profiles is summarised. 33 refs. Accession no.179274 Item 343 Rubber Chemistry and Technology 153,No.3,July/Aug.,1980,p.437-511 APPLICATIONS OF THERMAL ANALYTICAL PROCEDURES IN THE STUDY OF ELASTOMERS AND ELASTOMER SYSTEMS Brazier D W A review is presented of papers published since 1969 on DTA, DSC, TGA, derivative TGA and thermomechanical analysis. 119 refs. Accession no.157585

Item 345 Journal of Applied Polymer Science 25,No.5,May 1980,p.901-20 MOLECULAR WEIGHT CHARACTERISATION OF POLYBUTADIENE RUBBER WITH HIGH MOLECULAR WEIGHT AND BROAD MOLECULAR WEIGHT DISTRIBUTION Ambler M R The molecular weight characterisation of two samples of polybutadiene rubber of broad molecular weight distribution and high molecular weight by membrane osmometry, light scattering, and universal calibration of GPC was found. Correlation of molecular weight results for the two samples were possible only after (1) correction of membrane osmometry data for ‘diffusion layer’ and ‘solute permeability’ or ‘reflection’ effects were made and (2) GPC column sets were established with no bondspreading effects and with a wide molecular weight range of resolution. 15 refs. Accession no.153461 Item 346 RRI MALAYSIA. PROC.INT. RUBB.CONFERENCE. VOL.5 KUALA LUMPUR, Oct.1975, p.313-23. CONFER. 012 CARBON DIOXIDE NUMBER OF FIELD AND CENTRIFUGED NATURAL RUBBER LATICES Sundaram P; Calvert K O The various stages of NR latex from the time it is tapped from the tree in malaysia to arrival in the UK are discussed. The changes in carbon dioxide number which occur in field latex, before and after ammoniation, and the effects of centrifuging and storage of concentrate prior to and during shipment in bulk to the uk are described. Possible substrates for carbon dioxide production in fresh field latex are also considered. 7 refs. MALAYSIA; UK

Accession no.145733 Item 344 Members Rept.49 Shawbury, 1980, pp.12. 12ins. 2copies. 26/6/80. 91T HIGH PERFORMANCE LIQUID CHROMATOGRAPHY - ANALYTICAL APPLICATIONS IN THE RUBBER AND PLASTICS INDUSTRIES Sidwell J A Rubber & Plastics Research Assn.of Gt.Britain RUBBER & PLASTICS RA.MEMBERS REPT.049 This report details some of the high-performance liquid chromatography work carried out at RAPRA and reviews reported in the literature. 11 refs. RUBBER & PLASTICS RESEARCH ASSN.OF GT.BRITAIN Accession no.154074

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Item 347 Kautchuk und Gummi Kunststoffe 32, No.1, Jan.1979, p.18-22 German HIGH PERFORMANCE LIQUID CHROMATOGRAPHY IN ANALYSIS OF RUBBER Gross D; Strauss K The use of high performance liquid chromatography in the determination of optimum eluent, qualitativ separation of additives and in the quantitative assessment of antidegradants and accelerators is discussed. The preparation of samples for analysis, kinetic investigations and concentration of lipophilic substances from aqueous solutions are described. 15 refs. Accession no.131071

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References and Abstracts

Item 348 Plastics and Rubber: Materials and Applications 2, No.2, May 1977, p.59-64 SIGNIFICANCE OF NON-VOLATILE ACIDS IN NATURAL RUBBER LATEX Calvert K O

Item 351 Rubber India 8, No.1, Feb.1974, p.31-3 CARBON DIOXIDE NUMBER OF NATURAL RUBBER LATEX. I Calvert K O; Smith R K

Results of a quantitative determination of the non-volatile acids content of NR latex, obtained for fifty bulk shipments of five types, showed that non-volatile acids, other than higher fatty acids, accounted for half of the total acidic constituents in commercial high-ammonia latex of low volatile fatty acid content. The effects of nonvolatile acids on latex stability are discussed. 11 refs. Accession no.117101

A gravimetric method is described for the determination of the carbon dioxide (carbonate and bicarbonate) content of NR latex. By addition of carbonate to latex, it is established that one mole of carbon dioxide is equivalent to two moles of potassium hydroxide. The carbon dioxide number of latex is defined, therefore, in comparable terms to koh number and volatile fatty acid (vfa) number. Examination of nearly fifty bulk shipments of latex, after arrival in the UK, shows that carbon dioxide number accounts for a sizeable part of koh number and is directly related to vfa number over a wide range. It is also shown that the reduction in mechanical stability of latex due to an increase in the carbon dioxide number is approximately half of that effected by a vfa number increase of the same magnitude. 5 refs. Accession no.37252

Item 349 Rubber Chemistry and Technology 49, No.4, Sept./OCT.1976, p.1060-7 CONTRIBUTION TO IDENTIFICATION AND QUANTITATIVE DETERMINATION OF CARBON BLACK IN VULCANISATES BY THERMOGRAVIMETRIC ANALYSIS Pautrat R; Metivier B; Marteau J Experiments verified that, in a number of cases, thermogravimetric analysis permitted quantitative determination and identification of carbon blacks in the free state or in vulcanised compounds. The proper operating conditions could give sufficiently good reproducibility and adequate precisiion for most routine analyses. 12 refs. Accession no.101790 Item 350 Rubber Age 108, No.3,MARCH 1976, p.41-9 DETERMINATION OF ADDITIVES WITH HPLC AND TLC Sulliva A B; Kuhls G H; Campbell R H

Item 352 Rubber Chemistry and Technology 46, No.3,30TH JULY 1973, p.653-785 RUBBER MICROSCOPY Kruse J A review is presented covering the following topics: optical and mechanical properties of gum NR and synthetic rubbers and their vulcanisates; microstructure of carbon black in rubbers and its influence on rubber distribution; qualitative and quantitative determination of carbon blacks in rubbers; microscopical investigation of vulcanisates containg light coloured fillers and factice; microscopical appearance of reclaimed rubber; and preparation of specimens for observation. 111 refs. Accession no.35818

The use of liquid chromatography for the quantitative determination of accelerators and antidegradants in rubber is described. Thin layer chromatography was used for the identification of individual additives. Accession no.59514

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Subject Index

Subject Index A ABSORBANCE, 236 ABSORPTION, 184 256 269 330 ABSORPTION SPECTRA, 137 246 272 278 313 ACCELERATED TEST, 51 81 277 ACCELERATOR, 2 5 28 31 61 65 92 133 135 150 186 187 205 254 268 273 300 307 321 327 329 331 336 339 347 ACCURACY, 136 138 268 ACETIC ANHYDRIDE, 143 ACETONE, 31 161 268 ACETONITRILE, 161 ACID TREATMENT, 136 272 ACIDITY, 313 ACIDOLYSIS, 3 ACOUSTIC SPECTROSCOPY, 58 ACRYLATE, 81 ACRYLIC RUBBER, 15 ACRYLONITRILE, 186 189 259 269 ACRYLONITRILE-BUTADIENE COPOLYMER, 291 ACTIVATION ENERGY, 64 69 256 263 270 271 294 ACTIVATOR, 8 31 223 321 ADDITIVE, 2 19 22 25 31 61 65 79 83 84 85 99 109 112 133 134 135 137 138 140 143 150 152 161 162 185 186 187 192 193 194 195 198 201 205 214 216 223 229 232 240 241 244 247 254 255 268 269 270 272 273 275 283 296 298 303 307 313 318 321 325 326 329 331 333 334 339 347 350 ADHESION, 43 47 83 103 152 154 192 203 225 231 266 324 ADSORPTION, 76 107 135 145 223 272 298 301 303 325 AGEING, 1 15 23 44 51 57 69 81 90 91 95 110 125 141 147 183 189 198 217 264 269 285 297 314 342 AGGLOMERATE, 45 135 AGGLOMERATION, 134 223 303 AGGREGATE, 59 83 134 185 235 272 303 333 AIR SAMPLING, 186 ALCOHOL, 186 268 ALDEHYDE, 269 301

ALUMINIUM CHLORIDE, 278 AMIDE, 175 269 AMINE, 162 186 187 268 AMMONIA, 34 269 346 AMMONIUM PERCHLORATE, 101 AMORPHOUS, 151 296 303 ANISOTROPY, 91 183 296 298 ANTIOXIDANT, 55 81 87 239 255 296 313 336 339 ANTIOZONANT, 162 214 239 ANTISTATIC AGENT, 339 APPLICATION, 7 127 143 174 178 192 242 247 269 274 283 287 297 306 313 317 AQUEOUS, 23 347 ARBORESCENCE, 284 ARRHENIUS’S LAW, 124 ARTIFICIAL BREAST, 297 ASBESTOS, 186 ASH CONTENT, 50 ATOMIC ABSORPTION SPECTROSCOPY, 12 28 ATOMIC EMISSION SPECTROMETRY, 306 ATOMIC FORCE MICROSCOPY, 9 21 23 83 155 170 185 231 247 274 275 ATTENUATED TOTAL REFLECTION SPECTROSCOPY, 114 192 198 223 AUGER ELECTRON SPECTROSCOPY, 272 320 324 AUTOMATION, 57 113 292 AUTOMOTIVE APPLICATION, 192 242 269 274 AZEOTROPIC, 159

B BABY FEED BOTTLE, 268 BACK-SCATTERING, 303 BARRIER PROPERTIES, 32 247 BATTERY, 143 BENTONITE, 232 305 BENZENE, 66 186 270 325 BENZOIC ACID, 281 BENZONITRILE, 221 BENZOTHIAZOLE, 31 307 BINDING ENERGY, 143 152 272 BIOCOMPATIBILITY, 206 287 BIODEGRADATION, 287 297

BIOMEDICAL APPLICATION, 287 297 BIREFRINGENCE, 10 282 296 BLEND, 15 26 35 41 45 58 61 103 106 107 125 129 133 137 139 158 166 170 171 172 176 181 209 221 228 231 238 270 313 318 321 BLOOM, 175 189 216 321 BLOWING AGENT, 339 BOND SCISSION, 134 270 BONDING, 31 43 62 117 152 154 185 225 266 269 BONDING AGENT, 152 293 BOTTLE, 220 268 BOUND RUBBER, 22 25 38 120 298 BOUND SOLVENT, 40 BOUNDARY LAYER, 152 BRAKING, 58 BRANCHING, 131 140 243 284 299 BRASS, 154 203 324 BREAKER, 154 BREAKING STRESS, 274 BROMINATED, 137 273 BROMINATION, 52 BROMOBUTYL RUBBER, 323 BROMOMETHYLSTYRENE COPOLYMER, 137 BROMOSUCCINIMIDE, 52 BUILDING APPLICATION, 127 BUTADIENE, 25 259 292 BUTADIENE COPOLYMER, 210 284 323 BUTADIENE-ACRYLONITRILE COPOLYMER, 16 34 87 89 99 103 129 160 170 175 189 195 198 200 221 224 259 260 269 291 294 295 323 336 BUTADIENEMETHYLSTYRENE COPOLYMER, 16 BUTADIENE-STYRENE COPOLYMER, 10 11 13 14 21 25 40 44 45 58 61 86 89 91 107 113 125 133 138 139 142 168 170 176 183 185 195 209 228 232 235 238 241 247 271 292 303 305 323 332 BUTYL ACRYLATE POLYMER, 312 BUTYL PHTHALATE, 143

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Subject Index

BUTYL RUBBER, 35 61 62 83 107 195 331 332 BUTYLBENZOTHIAZOLE SULFENAMIDE, 244 BY-PRODUCT, 28 226

C CALCIUM CARBONATE, 186 321 CALCULATION, 100 115 142 153 213 214 233 243 249 250 256 257 261 263 267 282 CALENDERING, 200 CALIBRATION, 21 86 136 138 211 299 317 345 CALORIMETRY, 48 64 105 128 196 342 CAR TYRE, 135 154 CARBAMATE, 31 CARBON, 76 208 259 272 303 CARBON 13, 1 61 84 132 208 226 244 278 292 312 313 327 329 331 337 CARBON BLACK, 11 16 19 22 25 38 39 42 45 56 58 59 61 65 76 83 91 93 95 96 97 104 108 115 117 125 137 138 140 147 152 153 160 161 169 183 186 187 194 195 198 200 201 205 229 235 237 238 244 265 266 272 273 275 283 290 298 303 314 321 325 326 333 336 338 349 352 CARBON DIOXIDE, 256 346 351 CARBON DISULFIDE, 246 CARBON GEL, 38 298 CARBON SULFIDE, 186 CARBON TETRACHLORIDE, 80 CARBONATE, 351 CARBONYL INDEX, 197 CASE HISTORY, 266 CAST FILM, 66 296 308 CASTING, 20 296 CATALYST, 24 26 74 131 140 151 191 227 278 313 CHAIN BRANCHING, 140 270 CHAIN DYNAMICS, 90 125 273 285 CHAIN ENTANGLEMENT, 57 139 298 CHAIN EXTENDER, 280 CHAIN LENGTH, 31 249 313 CHAIN MOBILITY, 286 298 CHAIN SCISSION, 6 48 67 71 101 119 197 236 270 321 CHAIN STIFFNESS, 61 CHAIN TRANSFER AGENT, 308 CHAR FORMATION, 52

138

CHEMICAL ANALYSIS, 42 51 322 323 335 348 CHEMICAL CLEAVAGE, 55 67 CHEMICAL COMPOSITION, 26 47 152 249 336 348 CHEMICAL DEGRADATION, 90 269 CHEMICAL ENVIRONMENT, 91 CHEMICAL PLANT, 144 CHEMICAL PROPERTIES, 152 208 269 274 CHEMICAL RESISTANCE, 152 260 269 274 CHEMICAL SHIFT, 61 226 278 297 298 331 CHEMICAL STRUCTURE, 1 4 6 23 24 25 26 27 30 31 33 38 61 65 78 88 106 107 120 121 126 130 131 132 137 139 140 142 143 149 156 160 165 173 174 177 179 180 181 187 195 198 203 206 208 211 212 214 226 227 233 234 243 246 249 250 251 252 259 261 270 272 277 278 280 281 284 286 292 295 298 307 309 313 CHEMILUMINESCENCE, 184 186 CHINA CLAY, 186 CHLORINATED POLYETHYLENE, 129 CHLORINATED RUBBER, 69 CHLORINE, 28 CHLOROBUTYL RUBBER, 28 323 CHLORODIMETHYLSILANE, 284 CHROMATOGRAPHY, 2 24 31 33 39 40 49 53 70 71 77 100 107 121 122 139 140 144 145 150 153 160 163 171 177 186 192 202 210 212 214 220 233 238 242 243 248 249 255 258 267 268 270 281 284 288 289 300 306 310 316 339 CHROMIUM COMPOUND, 26 CHROMOPHORE, 71 286 CIS-CONTENT, 191 226 CLEAVAGE, 55 67 236 CLONE, 30 46 49 50 123 COAGULATION, 138 139 COALESCENCE, 23 247 COATING, 23 88 247 283 313 COMPATIBILITY, 170 COMPLEX IMPEDANCE, 143 COMPLEX MODULUS, 135 COMPLEX VISCOSITY, 140 COMPOSITE, 38 78 93 108 120

147 157 158 169 170 171 172 180 200 222 293 320 COMPOUNDING, 53 55 61 135 137 139 140 185 195 242 270 273 296 298 303 321 COMPRESSION MOULDING, 270 278 296 COMPRESSION PROPERTIES, 134 COMPUTER AIDED ANALYSIS, 61 113 136 143 152 185 271 274 278 297 298 COMPUTER SIMULATION, 188 218 219 271 CONDOM, 88 CONDUCTIVE FILLER, 272 CONDUCTIVE RUBBER, 143 CONFERENCE, 134 135 136 137 138 139 140 185 186 187 188 247 268 269 270 271 272 273 274 278 296 297 298 303 321 CONJUGATED BOND, 321 CONTACT ANGLE, 47 192 242 313 CONTAMINATION, 152 266 CONTRAST, 9 59 253 COOLING, 207 278 303 304 COPOLYMER COMPOSITION, 139 151 159 260 278 288 292 328 CORD, 43 CORE-SHELL, 59 COUPLING AGENT, 10 83 135 185 CRACKING, 231 274 CROSS-POLARISATION, 1 61 79 132 CROSS-SECTION, 152 CROSSLINK DENSITY, 1 3 5 21 35 47 57 61 63 69 110 111 119 130 134 135 161 205 236 237 245 263 269 270 273 274 290 296 321 322 326 327 329 337 CROSSLINKING, 1 15 17 27 37 39 48 52 54 61 62 63 64 70 72 74 79 81 84 85 91 95 97 110 111 119 124 133 134 135 136 139 146 147 150 151 152 168 179 188 197 199 205 208 225 244 245 254 257 263 264 266 269 270 273 274 283 285 296 308 313 321 326 329 331 332 337 CROSSLINKING AGENT, 37 57 263 CROSSLINKING PHENOMENA, 15 31 39 55 119 178 269 CRUMB RUBBER, 44

Subject Index

CRYSTALLINITY, 4 26 78 82 103 151 155 207 213 214 219 252 259 278 280 296 303 CRYSTALLISATION, 4 17 20 66 77 103 118 259 271 278 282 296 315 321 CRYSTALLOGRAPHY, 203 333 CURE, 47 58 61 105 150 319 342 CURE TIME, 31 54 61 63 106 133 135 137 140 213 232 270 271 283 293 294 296 307 313 321 322 329 331 338 CURING, 1 62 64 74 95 106 110 111 130 140 147 150 152 153 178 196 200 206 208 236 263 270 283 293 301 313 322 CURING AGENT, 2 28 31 35 37 55 57 61 74 79 92 133 137 153 161 186 187 216 232 244 254 263 269 270 273 283 296 321 326 328 331 332 336 337 338 CURING SYSTEM, 31 44 61 147 187 223 268 273 CURING TEMPERATURE, 2 31 61 137 140 150 187 270 271 283 296 313 321 329 CURVE FITTING, 61 298 CUT GROWTH, 296 CYANO GROUP, 259 CYCLISATION, 236 307 CYCLOHEXANE, 10 107 186 296 325 CYCLOHEXENE, 221 CYCLOHEXYL BENZOTHIAZOLE SULFENAMIDE, 31 61 150 321 338

D DAMAGE, 136 DAMPING, 234 DECAY, 57 91 183 DECOMPOSITION, 31 55 101 160 187 208 313 DECOMPOSITION PRODUCT, 52 101 328 338 DEFECT, 219 273 274 285 296 DEFORMATION, 58 155 185 247 296 303 DEGRADATION, 1 15 23 41 44 48 51 57 67 69 71 72 73 81 95 98 101 110 125 146 147 180 183 189 197 198 204 217 226 228 264 269 277 285 291 297 314 318 338 DEGRADATION PRODUCT, 1 98 147 197 221

DEHYDROCHLORINATION, 28 DELAMINATION, 136 DENSITY, 4 135 136 137 218 256 271 DENSITY GRADIENT, 273 DEPOLARISATION, 102 DEPROTEINISATION, 47 70 296 309 315 DEPTH PROFILING, 51 167 184 DERIVATIVE THERMOGRAVIMETRY, 228 DESORPTION, 186 DETECTION LIMIT, 186 DEUTERATED, 182 DEVULCANISATION, 42 134 270 DI-TERT-BUTYL-P-CRESOL, 31 313 DIALLYL PHTHALATE, 105 DIBUTYL PHTHALATE, 16 135 DIBUTYL SEBACATE, 16 DIBUTYLMETHYLPHENOL, 239 DIBUTYLTIN DILAURATE, 74 DICHLOROETHANE, 313 DICHLOROMETHANE, 31 186 268 313 DICHROISM, 10 DICUMYL PEROXIDE, 47 79 270 296 321 328 337 DICYCLOPENTADIENE TERPOLYMER, 140 DIELECTRIC CONSTANT, 136 161 DIELECTRIC LOSS, 294 DIELECTRIC PROPERTIES, 95 136 264 322 DIELECTRIC SPECTROSCOPY, 264 DIELS-ALDER REACTION, 85 DIENE, 85 DIETHOXYMETHYLSILANE, 29 DIETHYLAMINE, 186 DIETHYLDITHIOCARBAMIC ACID, 187 DIFFERENTIAL REFRACTOMETRY, 210 DIFFERENTIAL SCANNING CALORIMETRY, 2 19 23 26 27 33 48 53 69 77 78 81 102 105 122 124 125 128 133 134 139 143 147 151 159 179 188 196 197 204 207 214 227 250 251 252 259 262 263 271 278 283 310 313 318 322 342 343 DIFFERENTIAL THERMAL ANALYSIS, 2 19 23 26 27 33 48 53 69 77 78 81 102 105 122 124 125 128 133 134 139 143 147 150 151 159 179 188 196

197 204 207 214 227 250 251 252 259 262 263 271 278 283 310 313 318 DIFFRACTION, 219 DIFFUSION, 32 90 112 133 154 184 192 206 218 220 273 285 317 DIGLYCIDYL ETHER EPOXY RESIN, 18 DIMETHYLAMINE, 186 DIMETHYLBUTENE, 92 DIMETHYLSILOXANE COPOLYMER, 249 288 DIMETHYLSULFOXIDE, 34 DINITROGEN TRIOXIDE, 108 DINITROPHENYLHYDRAZINE, 301 DIPHENYL ETHER, 31 DIPHENYL GUANIDINE, 112 DIPHENYLMETHANE DIISOCYANATE, 27 280 DIRECT TANDEM MASS SPECTROMETRY, 334 DISPERSE PHASE, 157 DISPERSION, 45 83 135 140 148 157 171 176 185 223 229 235 247 272 DITHIOCARBAMATE, 160 254 DOMAIN, 76 116 139 151 155 274 280 311 DOPING, 136 DOUBLE BOND, 61 137 187 259 272 313 321 337 DRY RUBBER CONTENT, 46 84 DYNAMIC CONTACT ANGLE, 260 DYNAMIC MECHANICAL ANALYSIS, 27 58 102 122 140 143 180 DYNAMIC MECHANICAL PROPERTIES, 27 115 119 125 135 139 140 180 251 262 303 DYNAMIC MECHANICAL SPECTROSCOPY, 131 DYNAMIC MECHANICAL THERMAL ANALYSIS, 62 259 DYNAMIC MODULI, 135 286 303 DYNAMIC PROPERTIES, 27 87 115 119 125 135 139 140 180 195 234 251 262 285 303 DYNAMIC VISCOSITY, 140

E ECHO MAGNETISATION, 91 EFFICIENT VULCANISATION,

139

Subject Index

31 321 ELASTIC PROPERTIES, 17 47 58 61 131 139 140 188 237 247 271 303 322 333 327 ELECTRICAL APPLICATION, 143 ELECTRICAL PROPERTIES, 136 143 230 272 294 ELECTROACOUSTIC PROPERTIES, 68 ELECTROMAGNETIC PROPERTIES, 136 ELECTRON DENSITY, 143 ELECTRON DIFFRACTION, 66 219 ELECTRON IMPACT MASS SPECTROSCOPY, 334 ELECTRON MICROSCOPY, 18 148 170 176 219 225 240 245 266 ELECTRON SPECTROSCOPY, 76 94 272 ELECTROPHORESIS, 30 ELEMENTAL ANALYSIS, 159 272 298 ELUTION, 160 268 288 347 EMISSION, 145 184 186 301 319 EMISSION SPECTROSCOPY, 330 EMULSION, 61 84 139 183 209 END GROUP, 92 248 ENDOTHERMIC, 26 ENERGY DISPERSIVE X-RAY ANALYSIS, 152 176 ENTANGLEMENT, 37 167 182 234 244 285 ENTHALPY, 102 188 342 ENVIRONMENT, 186 208 319 EPICHLOROHYDRIN, 186 EPM, 136 151 278 EPOXIDATION, 48 72 250 313 EPOXIDISED NR, 48 72 EPOXY RESIN, 18 EQUATION, 1 10 16 41 59 63 64 68 80 109 110 113 115 129 130 134 135 136 138 143 145 152 160 183 184 188 200 208 226 234 235 236 246 251 259 263 264 270 271 278 280 285 286 291 296 297 298 303 311 314 330 EQUILIBRIA, 105 236 244 263 296 EQUIPMENT, 1 21 156 190 198 216 253 268 302 304 316 ETHANOL, 143 268 313 ETHYLENE DIAMINE, 259 ETHYLENE GROUP, 61 251 270 298

140

ETHYLENE-PROPYLENE COPOLYMER, 99 129 136 151 180 278 ETHYLENE-PROPYLENEDIENE TERPOLYMER, 3 35 41 55 64 81 97 131 140 143 153 167 177 184 195 197 198 204 224 236 242 263 264 265 278 299 307 323 328 332 341 ETHYLENE-VINYL ACETATE COPOLYMER, 122 ETHYLIDENE NORBORNENE COPOLYMER, 307 328 ETHYLIDENE NORBORNENE TERPOLYMER, 140 EVANESCENT FIELD OPTICAL MICROSCOPY, 136 EXCLUSION CHROMATOGRAPHY, 24 40 49 53 70 139 192 210 242 249 281 288 316 318 EXPOSURE TIME, 152 269 297 303 EXTENDER, 134 138 336 EXTRACTABILITY, 224 EXTRACTION, 19 28 31 47 86 134 138 160 161 255 268 270 272 298 303 EXTRUSION, 131 134 192 270

F FAILURE, 152 167 225 231 266 273 274 296 FATIGUE, 231 273 296 FATTY ACID, 77 315 FIBRE CONTENT, 293 FIELD LATEX, 346 FIELD-FLOW FRACTIONATION, 40 139 316 FILLER, 3 10 11 16 19 22 25 39 45 58 59 60 61 65 78 83 89 93 95 96 103 104 109 115 120 125 135 137 138 140 147 148 152 153 157 160 161 169 183 185 186 187 193 194 195 198 200 201 202 205 222 223 229 232 235 238 240 241 244 247 265 272 273 275 283 290 298 303 305 314 321 325 326 333 334 336 338 339 FILLER CONTENT, 57 58 125 135 137 185 298 303 326 FILLER DISTRIBUTION, 58 137 185 222 FILM, 20 66 82 118 137 155 162 164 185 245 246 247 276 278 280 296 308

FINITE DIFFERENCE ANALYSIS, 134 271 FINITE ELEMENT ANALYSIS, 188 191 271 FLAME IONISATION, 31 307 FLAW, 167 296 FLEXURAL PROPERTIES, 135 259 274 322 FLOOR, 127 FLORY-REHNER THEORY, 57 134 FLOW, 45 140 152 270 271 FLOW ANALYSIS, 75 271 FLUORESCENCE, 256 287 321 FLUORESCENCE SPECTROSCOPY, 149 286 287 FLUORINATION, 313 FLUOROELASTOMER, 274 283 336 FLUOROPOLYMER, 99 224 FOOD-CONTACT APPLICATION, 99 224 FORMALDEHYDE, 186 FORMULATION, 48 51 53 99 111 209 231 242 276 283 300 319 335 336 FOURIER TRANSFORM, 61 85 140 152 246 269 278 296 297 298 302 313 315 321 323 330 337 FOURIER TRANSFORM INFRARED SPECTROSCOPY, 3 6 10 24 42 52 54 67 72 78 86 93 105 107 108 126 127 128 147 164 192 223 242 248 252 281 304 FRACTIONATION, 40 139 316 317 FRACTURE MORPHOLOGY, 20 40 44 46 59 66 76 83 107 116 165 167 202 219 222 231 240 311 FREE INDUCTION DECAY, 138 297 311 FREEZING POINT, 197 FREQUENCY, 27 58 61 135 136 139 140 185 234 297 298 303 FUEL CELL, 143 FUME, 186 319 FUMED SILICA, 120 272 FUNCTIONALITY, 248 263 273 322

G GAMMA-RAY, 81 132 GAS ABSORPTION, 256 GAS ADSORPTION, 303

Subject Index

GAS CHROMATOGRAPHY, 25 31 51 53 76 77 145 153 160 177 186 193 202 209 212 214 220 221 238 267 268 279 289 300 306 307 318 322 328 GAS DIFFUSION, 218 GAS LIQUID CHROMATOGRAPHY, 339 341 GEL, 29 59 70 84 156 257 297 298 313 317 GEL CONTENT, 52 277 308 309 GEL FRACTION, 134 197 270 GEL PERMEATION CHROMATOGRAPHY, 33 39 77 100 121 140 144 233 243 248 258 270 284 310 GLASS TRANSITION TEMPERATURE, 4 19 23 58 90 102 119 122 125 126 130 139 143 165 181 218 234 250 251 252 262 286 298 308 313 GLASSY, 298 303 GLOVE, 69 GOLF BALL, 111 GONIOMETRY, 313 GRAPHITE, 22 272 303 325 GRAPHITISATION, 76 303 GRAVIMETRIC ANALYSIS, 53 87 115 127 222 228 GREEN STRENGTH, 4 309 315 GREEN TYRE, 135 GRINDING, 270 GROUND RUBBER, 270 GUANIDINE, 31 GUAYULE, 296 313 GUM, 352 GUTTA PERCHA, 219

H HARD SEGMENT, 27 102 280 311 HARDNESS, 3 35 44 135 252 269 274 322 HEALTH HAZARD, 31 186 187 224 268 300 HEAT AGEING, 55 81 87 208 HEAT DEGRADATION, 1 6 81 95 101 134 141 146 180 208 226 238 291 HEAT RESISTANCE, 15 52 55 87 95 101 127 141 168 180 230 248 250 313 HEAT STABILISER, 87 141 230 HEATING, 61 138 208 268 272 303 HEATING RATE, 124 133 271

HETEROGENEITY, 79 229 273 288 311 HEVEA BRASILIENSIS, 49 50 70 123 309 315 HEXAMETHYLENE TETRAMINE, 112 HEXANE, 66 143 161 HIGH PERFORMANCE LIQUID CHROMATOGRAPHY, 28 31 39 53 71 92 160 339 341 344 HIGH-RESOLUTION, 19 136 298 HIGH-RESOLUTION ELECTRON MICROSCOPY, 219 HISTOGRAM, 183 185 274 314 HOMOGENEITY, 29 164 210 273 HYDROCARBON OIL, 152 HYDROGEN ABSTRACTION, 55 337 HYDROGEN FLUORIDE, 272 HYDROGENATED NBR, 269 HYDROLYSIS, 31 187 206 269 297 HYDROMETHYLSILOXANE COPOLYMER, 249 HYDROPHILIC, 83 HYDROPHOBIC, 73 135 HYDROXYL GROUP, 163 297 313 HYDROXYL-TERMINATED, 101 184 246 HYSTERESIS, 108 296

I IDENTIFICATION, 88 145 323 IIR, 35 61 62 83 107 195 IMAGE ANALYSIS, 134 185 274 IMAGING, 7 83 136 137 156 183 184 185 273 297 IMMOBILISATION, 19 298 IMPACT PROPERTIES, 47 IMPEDANCE, 136 143 IMPEDANCE SPECTROSCOPY, 143 IMPLANT, 297 IMPURITY, 296 IN-SITU, 82 294 304 IN-VACUO, 296 IN-VITRO, 297 IN-VIVO, 297 INDUCTION PERIOD, 31 124 270 271 INELASTIC NEUTRON SCATTERING, 22 INFRARED SPECTRA, 26 33 34 51 72 80 87 114 127 140 152 164 168 197 198 206 216 232

236 246 269 272 277 278 282 295 296 299 302 310 313 315 322 321 323 339 INFRARED SPECTROSCOPY, 3 6 10 24 26 33 34 36 42 47 48 51 53 54 67 72 78 80 87 93 105 107 114 126 127 128 140 152 164 168 172 191 192 197 198 206 209 216 223 232 236 242 246 248 252 269 272 277 278 281 282 295 296 299 302 304 310 313 315 318 321 323 330 337 INHIBITOR, 87 INITIATOR, 55 159 168 211 INORGANIC, 336 INTERACTION, 19 25 95 119 125 135 160 169 183 223 259 298 303 325 333 INTERFACIAL PROPERTIES, 19 38 95 117 119 125 133 169 298 INTERNAL STANDARD, 31 268 INTERPARTICLE DISTANCE, 185 INTERPHASE, 19 125 298 INVERSE GAS CHROMATOGRAPHY, 76 193 202 318 325 IODINE, 24 259 IODINE NUMBER, 54 IODOMETRY, 147 IRON, 297 IRRADIATION, 48 72 81 119 264 285 ISOBUTENE COPOLYMER, 137 273 ISOCYANATE, 102 ISOCYANIDE, 269 ISOELECTRIC POINT, 135 ISONITRILE, 269 ISOPRENE, 85 ISOTHERMAL, 20 124 133 184 283 325 ISOTROPY, 185 273 296

K KAOLIN, 186 KETONE, 186 301 KINETIC, 61 102 124 133 162 168 188 271 283 331 KINETIC ENERGY, 143 272 KINETICS, 8 41 62 74 124

L LAMINATE, 283 LASER DIFFRACTION, 134 135

141

Subject Index

LASER EMISSION SPECTRA, 60 LASER IONISATION MASS SPECTROMETRY, 324 LASER LIGHT SCATTERING, 139 288 LASER RAMAN SPECTROSCOPY, 207 303 LATEX, 6 23 46 48 49 50 68 70 84 86 100 123 138 139 164 226 245 276 308 346 348 351 LEACHING, 230 276 298 LEAD, 186 230 LEAST-SQUARES ANALYSIS, 86 303 LIGHT ABSORPTION, 160 LIGHT DEGRADATION, 197 198 LIGHT REFLECTION, 235 LIGHT SCATTERING, 109 139 157 257 261 284 316 321 345 LINE WIDTH, 136 298 LINOLEIC ACID, 77 LIPID, 47 297 LIQUID CHROMATOGRAPHY, 2 28 31 39 53 71 92 107 160 171 318 347 350 LIQUID CRYSTAL, 261 LIQUID NITROGEN, 268 303 304 LIQUID RUBBER, 39 48 63 LITHARGE, 283 LITHIUM ALUMINIUM HYDRIDE, 135 LITHIUM COMPOUND, 52 LOADING, 11 93 139 235 263 274 LOSS TANGENT, 58 139 294 303 LOW-ANGLE LASER LIGHT SCATTERING, 210 LUBRICANT, 269 339 LUMINESCENCE, 184

M MACHINE, 63 134 160 271 MAGIC ANGLE, 19 61 72 132 209 273 297 298 326 327 MAGIC ANGLE SPINNING, 1 29 37 61 MAGNESIUM, 3 26 227 MAGNETIC FIELD, 29 75 MAGNETIC RESONANCE IMAGING, 314 MAGNETISATION, 57 91 183 234 MAIN CHAIN, 85 263 270 321 MALDI-TOF SPECTROSCOPY, 73 249 MASS SPECTRA, 31 53 104 117 212 221 289 MASS SPECTROSCOPY, 31 33 39 53 73 76 101 104 117 150

142

211 212 221 249 267 279 289 291 300 306 318 334 339 MASTICATION, 37 132 MATHEMATICAL MODEL, 64 86 188 200 257 261 MATRIX, 125 286 MATRIX-ASSISTED LASER DESORPTION, 73 249 MECHANICAL PART, 269 274 MECHANICAL PROPERTIES, 1 3 4 5 9 10 17 20 21 27 35 43 44 47 55 57 59 61 62 69 75 78 81 83 87 93 103 108 110 125 130 134 135 136 139 140 143 151 152 155 172 180 181 185 188 195 222 231 234 237 247 252 259 261 263 269 270 271 273 274 276 277 282 286 293 296 298 303 305 308 309 321 322 327 329 333 352 MECHANICAL RECYCLING, 134 MECHANICAL SCANNING MICROSCOPY, 235 MEDICAL APPLICATION, 287 297 306 MELTING, 26 27 151 207 278 MELTING POINT, 4 122 278 MEMBRANE OSMOMETRY, 345 MERCAPTOBENZTHIAZOLE, 8 31 92 153 307 321 MERCURY LAMP, 67 METAL, 152 160 225 266 METALLOCENE, 131 151 278 METAPHENYL BISMALEIMIDE, 263 METHACRYLATE, 3 METHANOL, 160 186 268 313 METHYL BROMIDE, 145 METHYL ETHYL KETONE, 107 269 283 METHYL MERCAPTANE, 145 METHYL METHACRYLATE COPOLYMER, 119 288 METHYL STYRENE COPOLYMER, 137 273 METHYLBENZENE, 26 161 METHYLBENZOTHIAZOLE, 31 METHYLENE CHLORIDE, 268 MICROSCOPY, 10 20 40 44 45 53 68 83 93 96 111 129 134 135 136 137 139 155 170 176 185 190 214 216 231 235 240 245 275 287 352 MICROSTRUCTURE, 19 25 38 61 84 97 140 143 159 179 181 191 201 209 240 245 246 275 286 291 298 305 331 352

MICROWAVE DYNAMIC DIELECTRIC ANALYSIS, 95 MIGRATION, 73 99 112 142 162 183 192 224 230 239 242 297 321 MILLING, 138 192 223 MINERAL FILLER, 185 222 MIXING, 37 45 51 58 60 61 106 135 137 139 167 172 185 223 242 266 270 273 296 298 303 MIXING TIME, 61 106 235 298 MODEL, 117 150 183 188 207 234 243 270 271 280 285 303 314 337 MODEL COMPOUND, 77 92 321 337 MOLAR MASS, 49 90 MOLAR RATIO, 313 MOLECULAR CONFIGURATION, 219 246 298 MOLECULAR DYNAMICS, 22 115 125 182 218 286 298 MOLECULAR MOBILITY, 1 19 57 132 286 298 308 311 MOLECULAR MOTION, 1 11 37 102 182 183 273 285 MOLECULAR ORIENTATION, 16 20 118 273 MOLECULAR STRUCTURE, 1 4 6 23 24 25 26 27 30 31 33 38 47 61 65 78 88 106 107 120 121 126 130 131 132 137 139 140 142 143 149 152 156 160 165 173 174 177 179 180 181 187 195 198 203 206 208 211 212 214 226 227 233 234 243 246 249 250 251 252 259 261 270 272 277 278 280 281 284 286 292 295 298 307 309 313 318 321 323 332 336 337 MOLECULAR WEIGHT, 6 16 24 30 46 47 67 70 71 100 106 116 122 123 126 130 131 139 140 142 150 163 201 211 226 233 236 248 251 256 270 276 277 284 288 298 299 308 313 316 317 318 345 MOLECULAR WEIGHT DISTRIBUTION, 46 122 123 130 131 139 140 162 199 236 277 288 298 299 309 316 345 MONITORING, 1 86 184 235 MONODISPERSE, 243 MONOMER, 48 86 186 259 286 MONOMER RATIO, 299 MONTMORILLONITE, 222 MOONEY VISCOSITY, 40 49 50

Subject Index

131 135 139 140 195 299 MOONEY-RIVLIN EQUATION, 10 57 MORPHOLINE, 186 MORPHOLINOTHIOBENZOTHIAZOLE SULPHENAMIDE, 5 MORPHOLOGY, 15 20 40 44 46 59 66 76 83 93 106 107 116 120 134 135 136 137 139 147 148 165 167 170 176 202 219 222 231 240 272 273 274 303 311

N NANOCOMPOSITE, 222 NAPHTHALENE DIISOCYANATE, 280 323 NAPHTHENIC OIL, 138 NATURAL FIBRE-REINFORCED RUBBER, 293 NATURAL RUBBER, 1 4 5 6 8 20 30 39 46 47 48 49 50 57 58 61 62 65 66 67 68 69 70 71 72 77 82 85 89 91 93 95 99 100 103 106 118 119 123 132 134 142 146 154 161 162 169 173 176 183 195 200 208 209 220 223 224 226 228 233 235 237 238 239 244 245 271 276 279 282 296 309 313 314 315 316 321 327 332 334 337 338 341 344 346 348 351 352 NATURAL RUBBER COPOLYMER, 119 NBR, 89 129 160 200 260 294 295 323 NEAR EDGE X-RAY ABSORPTION FINE STRUCTURE SPECTROSCOPY, 137 NEAR-INFRARED SPECTROSCOPY, 80 NEOPRENE, 66 89 137 195 198 212 213 221 312 NETWORK, 31 61 65 79 90 181 183 234 237 270 273 276 303 313 314 322 327 329 NEUTRON SCATTERING, 22 59 115 166 229 257 NITRILE RUBBER, 34 99 170 175 189 195 198 221 224 259 269 323 341 NITROGEN, 41 67 134 146 183 184 208 314 NITROGEN OXIDE, 108 186 187 268 NITROSAMINE, 108 153 186 187 268

NON-ISOTHERMAL, 124 271 NORBORNENE TERPOLYMER, 143 NORMALISING, 61 140 270 272 274 278 298 NUCLEAR MAGNETIC RESONANCE, 1 6 7 19 29 33 37 38 53 57 61 65 67 70 72 75 77 79 84 88 90 91 97 98 100 105 109 110 113 116 119 120 125 126 132 138 146 159 167 169 173 178 182 183 191 201 205 206 208 209 210 226 233 234 237 241 244 246 249 250 252 253 259 260 262 265 269 273 278 281 285 289 290 292 297 298 299 311 312 313 314 318 322 323 326 327 329 331 337

O ODOUR, 145 OIL, 134 138 152 OIL EXTENDED, 134 138 139 140 OIL PALM, 293 OIL RESISTANCE, 152 260 OLEIC ACID, 77 OPTICAL ANISOTROPY, 296 OPTICAL BIREFRINGENCE, 296 OPTICAL BRIGHTENER, 339 OPTICAL DENSITY, 272 OPTICAL DIFFRACTION, 219 OPTICAL FIBRE, 86 114 136 OPTICAL MICROSCOPY, 10 134 135 136 170 214 OPTICAL PROPERTIES, 139 235 247 256 272 282 287 296 ORGANOSILICONE POLYMER, 222 ORIENTATION, 10 66 90 185 256 296 OSMOMETRY, 33 233 OXIDATION, 38 48 65 67 98 101 128 134 184 197 198 204 208 226 269 272 297 313 OXIDATION STABILISER, 87 OXIDATIVE DEGRADATION, 48 67 87 98 101 128 134 147 184 197 198 204 208 226 269 272 297 313 OXYGEN, 76 208 269 272 314 OXYGEN CONTENT, 272 OZONE DEGRADATION, 214 OZONOLYSIS, 121

P PALM FIBRE, 293 PALMITIC ACID, 31 PARAFFIN OIL, 143 PARTICLE, 134 184 219 247 272 303 PARTICLE SIZE, 38 59 68 96 123 134 135 147 185 195 202 219 240 247 270 298 303 305 325 333 PARTICLE SIZE DISTRIBUTION, 68 123 134 135 PEAK INTENSITY, 61 246 269 296 298 303 PEAK SHAPE ANALYSIS, 160 PENDANT GROUP, 61 298 313 PERMEABILITY, 220 247 256 273 PEROXIDE, 35 55 64 105 111 147 236 245 263 270 283 PEROXIDE VULCANISATION, 3 55 105 237 270 PETROLEUM WAX, 214 PH, 160 PHASE CONTRAST MICROSCOPY, 185 PHASE SEPARATION, 119 251 287 PHASE STRUCTURE, 137 139 171 227 274 PHENYLENE DIAMINE, 81 162 239 PHENYLHYDRAZINE, 48 PHOSPHORUS, 50 309 PHOTOCALORIMETRY, 48 PHOTODEGRADATION, 67 71 PHOTOELECTRON SPECTROSCOPY, 141 143 152 170 192 194 225 260 266 272 PHOTOMICROGRAPHY, 40 44 93 129 PHOTON ENERGY, 137 143 PHOTOOXIDATIVE DEGRADATION, 197 198 PHOTOSENSITISER, 67 71 PI TRANSITION, 272 PIGMENT, 247 339 PLASMA TREATMENT, 83 117 190 PLASTICISER, 16 23 34 60 143 171 217 336 339 POLARISATION, 79 136 273 POLARITY, 103 143 POLYACRYLONITRILE, 323 POLYBUTADIENE, 17 19 24 25 26 35 52 58 61 65 84 90 101

143

Subject Index

107 112 121 125 126 128 137 138 144 163 166 181 182 184 191 201 209 210 211 227 228 238 246 250 251 252 284 285 286 292 298 308 312 323 332 337 345 POLYBUTADIENE URETHANE, 246 POLYBUTYLENE, 114 137 165 POLYCHLOROPRENE, 66 89 137 170 195 198 212 213 221 312 336 POLYDIENE, 19 22 26 65 79 84 85 133 188 204 212 213 223 292 308 309 POLYDIMETHYL SILOXANE, 27 73 83 193 202 207 218 222 248 256 257 270 281 297 306 POLYDISPERSITY, 68 130 139 140 270 POLYEPOXIDE, 18 POLYESTER-URETHANE, 287 304 311 313 323 POLYETHER URETHANE, 102 POLYETHYLENE, 129 323 POLYISOCYANATE, 313 POLYISOPRENE, 22 31 38 47 59 61 65 71 78 79 80 85 92 98 105 111 112 115 120 133 154 181 191 223 282 296 309 312 332 341 POLYMERIC PLASTICISER, 143 336 POLYMERISATION, 33 61 114 139 140 144 159 183 201 211 236 278 284 298 322 POLYMERISATION CATALYST, 24 26 140 151 227 278 POLYMERISATION INITIATOR, 55 159 211 POLYOL, 246 POLYOXYTETRAMETHYLENE, 280 POLYPHENYLMETHYLSILOXANE, 218 POLYPROPYLENE, 41 POLYSILOXANE, 29 206 222 297 POLYSTYRENE, 210 323 POLYSULFIDE, 92 150 POLYTETRAMETHYLENE OXIDE, 102 POLYTHIOETHER, 92 150 POLYUREA-URETHANE, 179 POLYURETHANE, 44 103 246 304 313 323 330 POLYURETHANE ELASTOMER, 15 74 102 155 179 280 311 POLYURETHANE ESTER, 287

144

304 313 POLYVINYL CHLORIDE, 16 POROD ANALYSIS, 116 POROSITY, 134 240 POSITRON ANNIHILATION LIFETIME SPECTROSCOPY, 11 23 POTENTIOMETRIC TITRATION, 13 PRECIPITATED SILICA, 61 135 185 PRESSURE, 270 271 303 325 PRINCIPAL COMPONENTS ANALYSIS, 292 PROBE, 136 286 PROBLEM PREVENTION, 53 PROCESSIBILITY, 15 135 140 143 171 299 PROCESSING, 171 172 186 192 236 247 267 294 300 PROCESSING AID, 339 PROCESSING OIL, 138 235 PROPYLENE, 299 PROTON MAGNETIC RESONANCE, 19 29 79 249 297 326 327 PROTON SPIN DIFFUSION SPECTROSCOPY, 116 PROTON SPIN RELAXATION, 90 138 285 PURITY, 296 313 PYROLYSIS, 42 51 101 158 238 268 279 289 291 338 PYROLYSIS GAS CHROMATOGRAPHY, 25 51 177 209 212 221 279 289 307 318 328 338 PYROLYSIS-INFRARED SPECTROPHOTOMETRY, 42 209 PYROLYSIS MASS SPECTROMETRY, 101 279

Q QUALITY CONTROL, 7 14 57 60 110 127 138 140 188 268 299 QUANTITATIVE ANALYSIS, 84 221 272 319 QUENCHING, 257 303

R RADIAL TYRE, 154 RADIATION DEGRADATION, 72 119 RAMAN SPECTROSCOPY, 76 85

86 108 126 145 164 191 207 303 318 321 323 RECYCLING, 18 42 44 134 230 267 270 REFLECTANCE SPECTROSCOPY, 114 REFRACTIVE INDEX, 139 281 REFRACTOMETRY, 210 REINFORCED PLASTIC, 158 320 REINFORCED RUBBER, 3 38 109 125 147 200 293 REINFORCEMENT, 10 135 185 195 229 303 333 REINFORCING FILLER, 39 135 272 RELAXATION MAP ANALYSIS SPECTROSCOPY, 102 RELAXATION TIME, 1 79 84 138 139 140 234 273 274 296 298 312 REPEATABILITY, 138 188 238 246 299 RESIDUAL CURING AGENT, 92 RESIDUAL MONOMER, 318 RESIDUAL UNSATURATION, 36 269 RESIDUAL WATER, 297 RESIDUE, 31 52 RESOLUTION, 136 314 RESORCINOL, 186 RETENTION TIME, 31 139 268 REVIEW, 4 7 53 55 65 156 169 174 176 178 190 209 217 240 253 254 280 302 318 319 342 343 352 RHEOLOGICAL PROPERTIES, 8 14 31 40 45 46 49 50 54 61 63 67 122 131 135 139 140 152 188 196 206 247 250 263 270 271 273 286 321 RICE HUSK ASH, 93 ROUGHNESS, 134 136 185 247 303 313 ROUND ROBIN TEST, 209 RUBBER TO METAL BONDING, 43 62 117 152 154 225 266

S SAMPLING, 186 SATURATION, 61 175 189 SCANNING ELECTRON MICROSCOPY, 9 18 38 44 45 66 68 82 93 96 118 120 148 152 170 176 222 225 231 240 252 266 276 293 324 SCANNING PROBE MICROSCOPY, 40 111 139

Subject Index

275 SCISSION, 6 48 67 71 101 119 197 236 270 314 SCORCH, 270 271 293 SCORCH TIME, 232 270 SCRAP, 18 42 134 267 270 SEAL, 192 220 242 269 274 SECONDARY AMINE, 186 187 268 SECONDARY ION MASS SPECTROSCOPY, 39 76 117 211 320 332 SEQUENCE DISTRIBUTION, 61 121 249 260 278 SERVICE LIFE, 112 135 SHEAR PROPERTIES, 61 62 134 270 271 322 SILANE, 10 29 83 109 135 185 193 284 SILICA, 10 11 25 29 45 61 65 78 83 91 93 103 109 120 125 135 137 148 183 185 186 193 202 223 239 249 272 297 301 321 SILICONE COPOLYMER, 27 206 249 SILICONE POLYMER, 29 206 222 297 SILICONE RUBBER, 9 63 73 94 99 141 148 202 222 224 270 297 323 SIZE EXCLUSION CHROMATOGRAPHY, 24 40 49 53 70 139 192 210 242 249 281 288 316 318 SMALL ANGLE NEUTRON SCATTERING, 59 166 SMALL ANGLE X-RAY SCATTERING, 179 SODIUM CARBONATE, 313 SODIUM DODECYLSULPHATE, 23 SOFT SEGMENT, 27 102 280 311 SOL FRACTION, 47 270 SOLID STATE, 19 29 61 79 116 125 132 208 244 273 298 311 329 331 337 SOLUBILITY, 103 189 297 313 321 SOLUTION, 6 20 66 67 143 183 186 219 246 250 268 278 296 347 SOLVENT, 16 31 66 143 160 161 186 188 226 246 250 257 258 268 269 273 283 298 SOLVENT ABSORPTION, 269 SOLVENT EVAPORATION, 268 SOLVENT EXTRACTION, 19 31 47 134 138 255 268 270 298

303 SOXHLET EXTRACTION, 22 31 115 134 268 270 272 SPECTRAL ELEMENT ANALYSIS, 191 SPIN ECHO, 138 167 183 273 297 298 314 SPIN RELAXATION, 90 138 285 SPIN-LATTICE RELAXATION, 84 116 312 331 SPIN-SPIN RELAXATION, 57 138 234 241 298 SPORTS EQUIPMENT, 111 SQUALENE, 39 85 117 STABILISER, 87 141 180 230 STAINING, 245 STANDARD, 31 36 56 89 215 235 268 299 317 STANDARD MALAYSIAN RUBBER, 183 296 STANNIC OXIDE, 141 STAR-BRANCHED, 251 STAR-SHAPED, 166 243 STEARAMIDE, 189 STEARIC ACID, 8 31 77 187 273 321 331 STOICHIOMETRY, 269 272 273 313 STORAGE, 277 301 346 STORAGE LIFE, 216 STRAIN, 20 58 135 140 259 274 296 303 321 STRAIN CRYSTALLISATION, 296 STRESS, 75 134 139 269 274 296 STRESS-OPTICAL PROPERTIES, 296 STRESS RELAXATION, 140 274 282 296 STRESS-STRAIN PROPERTIES, 5 10 139 195 237 261 263 270 274 282 296 303 327 STRESSES, 75 134 139 269 274 296 STRETCHING, 20 78 151 155 185 274 STRUCTURAL ANALYSIS, 38 82 143 156 STYRENE, 25 86 138 139 238 245 292 STYRENE-ACRYLONITRILE COPOLYMER, 332 STYRENE-BUTADIENE RUBBER, 16 91 142 170 176 STYRENE-BUTADIENESTYRENE BLOCK COPOLYMER, 116 149 243 258 310 323 332

STYRENE-ISOPRENESTYRENE BLOCK COPOLYMER, 32 SULFENAMIDE, 31 150 187 244 300 SULFONATION, 32 143 SULFUR, 2 28 31 35 44 61 65 76 92 97 133 137 143 150 187 192 205 208 216 223 232 244 245 254 272 273 307 321 326 327 328 329 331 332 338 SULFUR CONTENT, 57 SULFUR VULCANISATION, 8 31 39 55 61 92 137 187 273 321 342 SULFURIC ACID, 135 143 SUPERCRITICAL FLUID CHROMATOGRAPHY, 255 SUPERCRITICAL FLUID EXTRACTION, 255 SURFACE ANALYSIS, 94 117 135 152 190 260 274 320 324 330 332 SURFACE AREA, 38 134 135 147 298 303 325 SURFACE CHEMISTRY, 104 135 320 SURFACE DEGRADATION, 134 239 274 SURFACE ENERGY, 47 76 192 325 SURFACE ENHANCED RAMAN SCATTERING, 145 SURFACE MIGRATION, 142 239 SURFACE PROPERTIES, 94 120 135 136 185 190 192 193 194 216 247 274 303 313 314 320 324 SURFACE STRUCTURE, 59 104 120 134 136 147 152 190 303 SURFACE TENSION, 260 303 SURFACE TREATMENT, 83 109 149 190 202 293 324 SURFACTANT, 84 164 SWELLING, 3 5 10 16 57 61 69 105 111 134 143 188 197 204 236 237 244 245 252 257 263 264 269 270 273 322 SWELLING RATIO, 52 SYNDIOTACTIC, 246 SYNTHETIC RUBBER, 9 10 40 41 69 75 94 105 113 125 128 129 158 174 177 178 190 279 289 312 323 352

T TACK, 47

145

Subject Index

TACKIFIER, 54 336 TALC, 45 186 TAN DELTA, 135 139 140 294 308 TAPPING MODE ATOMIC FORCE MICROSCOPY, 83 185 274 TEAR STRENGTH, 35 87 103 195 296 TEMPERATURE, 26 50 58 61 91 124 132 138 139 140 143 150 152 161 207 208 234 247 263 268 269 270 271 274 278 297 298 303 304 308 312 321 TENSILE PROPERTIES, 1 3 17 27 44 69 81 87 93 151 155 195 270 274 276 296 TEST EQUIPMENT, 62 96 113 184 188 196 235 263 279 291 316 TEST METHOD, 7 36 56 58 112 131 171 175 209 228 255 266 299 TEST SPECIMEN, 235 280 TETRACHLOROMETHANE, 80 TETRAETHYLTHIURAM DISULFIDE, 2 187 TETRAETHYLTHIURAM MONOSULFIDE, 2 TETRAHYDROFURAN, 161 281 288 TETRAMETHYLTHIURAM DISULFIDE, 2 28 44 112 133 153 321 331 338 TG, 4 19 58 102 119 125 126 139 143 181 218 250 251 252 262 286 298 308 313 THERMAL AGEING, 91 95 141 314 THERMAL ANALYSIS, 33 64 81 102 127 134 139 143 147 150 179 188 196 217 271 277 278 283 313 318 336 343 THERMAL BLACK, 76 THERMAL DEGRADATION, 1 6 31 55 81 87 95 101 134 141 146 160 180 208 226 238 291 313 328 338 THERMAL FIELD-FLOW FRACTIONATION, 40 139 316 THERMAL OXIDATION, 98 THERMAL PROPERTIES, 4 14 19 26 27 95 101 102 139 143 151 159 181 188 207 222 227 234 247 250 251 252 257 262 271 278 282 286 296 298 313 318 321 THERMAL STABILITY, 15 55 87 95 101 127 141 168 180 230

146

248 250 313 THERMALLY STIMULATED DEPOLARISATION, 102 THERMOANALYTICAL, 53 THERMOGRAM, 143 147 228 313 THERMOGRAVIMETRIC ANALYSIS, 41 52 53 81 87 115 127 134 150 159 161 222 228 313 318 336 349 THERMOLYSIS, 150 THERMOMECHANICAL ANALYSIS, 106 180 199 343 THERMOOXIDATION, 65 98 184 208 THERMOOXIDATIVE DEGRADATION, 87 134 147 198 204 208 THICKNESS, 136 137 155 278 296 311 THIN FILM, 20 66 82 118 155 278 296 THIN LAYER CHROMATOGRAPHY, 267 339 341 350 THIURAM, 31 187 300 THIURAM SULFIDE, 254 TIME OF FLIGHT, 22 39 73 104 115 117 211 249 320 TITANIUM, 24 26 227 TITRATION, 135 313 322 TOLUENE, 26 161 288 298 TOLUENE DIISOCYANATE, 27 102 323 TORQUE, 61 140 270 294 321 TRANS-CONTENT, 226 TRANSMISSION ELECTRON MICROSCOPY, 9 18 20 38 66 68 82 96 118 120 129 148 170 176 219 222 225 231 240 245 266 276 TRANSMISSION FLUID, 269 274 TRANSMISSION SPECTROSCOPY, 158 198 285 TREAD, 135 209 235 262 303 TREAD RUBBER, 58 209 TRIALLYLCYANURATE, 79 236 283 TRIFLUOROACETIC ACID, 313 TRIISOBUTYL ALUMINIUM, 24 TROUBLESHOOTING, 53 TWO-PHASE, 139 272 311 TYRE, 18 40 44 58 117 135 136 137 139 154 183 187 209 216 234 235 262 267 303 324

U ULTRA HIGH MOLECULAR WEIGHT, 316 ULTRAMICROTOMY, 96 ULTRASONIC TEST, 200 322 ULTRAVIOLET IRRADIATION, 48 ULTRAVIOLET SPECTROSCOPY, 43 216 339 UNCURED, 61 83 140 151 235 UNFILLED, 11 61 146 247 269 270 273 298 URETHANE ELASTOMER, 74

V VANADIUM, 140 227 278 VAPOUR PRESSURE OSMOMETRY, 33 VIBRATIONAL SPECTROSCOPY, 26 33 34 51 72 76 85 86 87 108 114 126 127 140 145 152 164 191 197 198 207 216 232 236 246 269 272 277 278 295 296 299 302 303 310 313 315 VINYL ACETATE-ETHYLENE COPOLYMER, 122 VINYL CHLORIDE, 186 VINYL CYANIDE, 186 189 259 269 VINYL GROUP, 61 251 270 298 VISCOELASTIC PROPERTIES, 47 58 61 139 247 271 274 286 308 VISCOMETRY, 45 87 140 270 284 VISCOSITY, 40 45 46 49 50 63 67 135 139 140 152 206 247 250 270 271 VOID, 16 167 273 VOLATILISATION, 31 134 334 VOLATILITY, 160 186 268 334 348 VULCANISATE, 3 11 12 16 31 61 81 87 112 134 135 160 161 162 177 178 185 213 237 239 244 264 270 305 309 321 326 327 328 329 331 334 338 342 349 352 VULCANISATION, 1 2 3 5 8 28 31 39 47 54 55 61 65 81 85 92 97 105 106 124 133 135 137 140 141 150 178 186 187 188 196 205 217 232 236 237 254 263 268 269 270 271 273 276 294 296 299 300 301 303 305 307 319 321 342

Subject Index

VULCANISATION TIME, 31 61 106 135 137 140 213 270 293 294 296 307 313 VULCANISED, 83 145 221 228 244 331

W WASTE, 42 134 270 WATER, 20 31 269 272 297 WATER SOLUBLE, 12 WAVE NUMBER, 269 272 WAVEGUIDE, 136 WAVELENGTH, 136 160 WAX, 142 162 239 WEATHER RESISTANCE, 51 81 162 WEATHER STRIPPING, 192 242 WEIGHT LOSS, 87 147 336 WETTING, 152 242 WIDE ANGLE X-RAY SCATTERING, 3 259 280 WLF EQUATION, 122 286 312

X

Z

X-RAY ANALYSIS, 152 176 X-RAY FLUORESCENCE, 339 X-RAY MICROSCOPY, 137 324 X-RAY PHOTOELECTRON SPECTROSCOPY, 141 143 152 170 192 194 260 266 272 320 X-RAY SCATTERING, 3 26 33 102 103 116 151 156 174 179 203 213 222 227 240 259 275 280 303 339 X-RAY SPECTROSCOPY, 104 141 143 152 170 176 192 194 203 259 260 266 272

ZIEGLER-NATTA CATALYST, 24 140 ZINC, 3 12 111 192 223 ZINC DIETHYLDITHIOCARBAMATE, 2 187 ZINC DIMETHYLDITHIOCARBAMATE, 28 ZINC DITHIOCARBAMATE, 300 ZINC OXIDE, 2 8 28 31 137 186 187 273 321 331 ZINC STEARATE, 186 192 ZINC SULFIDE, 187

Y YIELD, 46 338 YOUNG’S MODULUS, 17 61 188 274 303 333

147

Subject Index

148