DEVELOPMENTS IN RUBBER TECHNOLOGY-2 Synthetic Rubbers THE DEVELOPMENTS SERIES Developments in many fields of science and technology occur at such a pace that frequently there is a long delay before information about them becomes available and usually it is inconveniently scattered among several journals. Developments Series books overcome these disadvantages by bringing together within one cover papers dealing with the latest trends and developments in a specific field of study and publishing them within six months of their being written. Many subjects are covered by the series, including food science and technology, polymer science, civil and public health engineering, pressure vessels, composite materials, concrete, building science, petroleum technology, geology, etc. Information on other titles in the series will gladly be sent on application to the publisher. DEVELOPMENTS IN RUBBER TECHNO LOGY-2 Synthetic Rubbers Edited by A. WHELAN and K. S. LEE National College of Rubber Technology, Holloway, London, UK APPLIED SCIENCE PUBLISHERS LTD LONDON APPLIED SCIENCE PUBLISHERS LTD RIPPLE ROAD, BARKING, ESSEX, ENGLAND British Library Cataloguing in Publication Data Developments in rubber technology.--(Developments series). 2: Synthetic rubbers I. Elastomers 2. Rubber I. Whelan, Anthony II. Lee, K. S. III. Series 678 TSI925 ISBN-13: 978-94-009-8110-2 e-ISBN-13: 978-94-009-8108-9 DOl: 10.1007/978-94-009-8108-9 WITH 80 TABLES AND 57 ILLUSTRATIONS (0 APPLIED SCIENCE PUBLISHERS LTD 1981 Softcover reprint of the hardcover 1st edition 1981 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publishers, Applied Science Publishers Ltd, Ripple Road, Barking, Essex, England PREFACE This book is intended for those people who have a knowledge or understanding of rubber materials and processes but who wish to update their knowledge. It should be read in conjunction with Developments in Rubber Technology-l as that volume discussed developments in natural rubber and selected special purpose synthetic rubbers as well as additives. The authors have been selected for their expertise in each particular field and we, as editors, would like to express our appreciation to the individual authors and also to their companies. Such a book would be impossible to produce without such active cooperation as we have received. Volumes 1 and 2 of Developments in Rubber Technology cover rubbers which are processed and vulcanised in the traditional manner. It is appreciated that the omission of non-vulcanised rubber materials (the so called thermoplastic elastomers) will be unwelcome to many readers but it is intended, because of the size of the subject, to cover these materials in a subsequent volume. A.W. K.S.L. v CONTENTS Preface v List of Contributors IX l. Trends in the Usage of Rubbery Materials J. A. BRYDSON 2. Styrene~Butadiene Rubber 21 J. A. BRYDSON 3. Developments in Acrylonitrile~Butadiene Rubber (NBR) and Future Prospects . 51 H. H. BERTRAM 4. Ethylene~Propylene Rubbers. 87 L. CORBELL! 5. Developments with Polychloroprene 131 J. C. BAMENT and J. G. PILLOW 6. Butyl and Halogenated Butyl Rubbers 155 W. D. GUNTER 7. Silicone Rubbers . 203 R. J. CUSH and H. W. WINNAN 8. Synthetic Polyisoprene Rubbers 233 M. J. SHUTTLEWORTH and A. A. WATSON Index. 269 vii LIST OF CONTRIBUTORS J. C. BAMENT Elas/omers Research Lahoratory, Du Pont (l rK ) Ltd, Maylands Avenue, Heme/ Hempstead, Herts HP2 7DP, UK H. H. BERTRAM Bayer AG, D-5090 Leverkusen, Bayerwerk, West Germany J. A. BRYDSON National College of Rubber Technology, The Polytechnic of North London, Holloway, London N7 8DB, UK L. CORBELL! MontedisonS.p.A.,DIMPjCER, Piazzale PrivatoDonegani 14, 44100 Ferrara, Italy R. J. CUSH Dow Corning Ltd, Barry, Glamorgan CF6 7YL, UK W. D. GUNTER Polysar Ltd, Sarnia, Ontario, Canada N7T 7M2 J. G. PILLOW Elastomers Research Laboratory, Du Pont (UK) Ltd, Maylands Avenue, Hemel Hempstead, Herts HP2 7DP, UK ix x LIST OF CONTRIBUTORS M. 1. SHUTTLEWORTH Compagnie Franqaise Goodyear, Centre Technique, Avenue des Tropiques, 91941 Les Ulis, France A. A. WATSON Compagnie Franqaise Goodyear, Centre Technique, Avenue des Tropiques, 91941 Les Ulis, France H. W. WIN NAN Dow Corning Ltd, Barry, Glamorgan CF6 7YL, UK Chapter 1 TRENDS IN THE USAGE OF RUBBERY MATERIALS J. A. BRYDSON National College of Rubber Technology, The Polytechnic of North London, Holloway, London, UK SUMMARY Thefuture pattern of rubber usage is predicted in the light ofexpected global changes in living standards and, specifically, methods of transportation. It is concluded that the car and the lorry It'ill become increasingly favoured methods of tramport. Whilst there It'il! continue to be an increasing demand for car OIrnership the increasing cost of energy is likely to lead /0 smaller, lighter cars as well as more careful patterns of usage. This will lead to a reduction in the amount of rubber used per car. Whilst non-automotive applications of rubber will continue to be developed the use of rubber will largely be determined by the automotive industries. This growth of rubber consumption will require an increase in car ownership to more than offset the amount of rubber used per car. The outlook for individual types of rubber, which are far from uniform, are reviewed. It is concluded that the rubber industry will have to work much harder and more effectively thanformerly to survive the next decade, and that companies that fail to undertake the necessary development work to ensure that their productsfind a ready market and those that make inefficient use of manpower, equipment and materials cannot be expected /0 enjoy a long-term prosperity. 1. INTRODUCTION Those of us who attempt to predict future trends cannot win. If our predictions turn out to be wrong, then we are simply discredited. If, on the I 2 J. A. BRYDSON other hand, our predictions turn out to be correct, then we are likely to be told that what we had predicted was obvious in any case. A less pleasant alternative is that we may make predictions which, when made, were not what people wanted to hear and when they prove to be correct, the person making the prediction is, somehow, held to blame for the occurrence of the event. Whilst predictions from an individual's point of view are games for masochists, there is a real need that they should be made. No organisation which hopes to have a successful, long-term future could reasonably expect to exist without making some assessment of what is likely to happen in the future. What, however, must be recognised is that situations may be expected to change and, consequently, it is necessary to update predictions as these changes occur. It is therefore reasonable that between writing this chapter and its publication, important changes may have occurred cJlld so my predictions may need to be modified. It will, however, be my aim in preparing this chapter to explain the basis for the predictions so that where changes have occurred in the underlying situation, the reader will be able to modify and adapt my predictions appropriately. I n order to try and predict trends in the usage of a particular material, it is necessary to consider a variety of underlying trends. Some of these underlying trends may be very long-term and others very short. Tt is clearly most sensible to determine the primary long-term trends and then to superimpose on them the secondary trends of shorter duration. In the specific case of the consideration of trends in the usage of rubbery materials, the following global underlying trends may be identified: I. Changes in standards of living 2. Changes in patterns of transportation 3. Changes in the design of automotive equipment 4. Changes in tyre design and the use of rubber in other automotive applications 5. Changes in non-automotive uses for rubber 6. Changes in raw material supplies 7. Trends in legislation, for example in areas associated with health, safety and toxicity 2. LONG-TERM UNDERLYING TRENDS The first two of the above list of underlying trends are obviously of a very long-term nature. The 20th century has, with the two interludes of the two