A. Whelan – författare

An overview of polymeric materials and their additives together with information on the processing, testing and properties of certain polymeric materials. This dictionary not only provides a definition of each term but also an explanation and any background information required along with several large appendices. Tradenames and trade marks are listed separately, allowing suppliers of different meaterials to be readily identified and extensive unit conversion tables are also included. The book is cross referenced throughout and all those involved with rubbers and plastics manufacture should find it useful as will any industrial scientist. It should be particularly useful to those concerned with the selection and use of plastics and rubbers, yet have limited training and experience of such materials.

In the field of plastics technology, the process of extrusion is widespread and important. It is employed in the compounding and pelletising of plastics materials, in their conversion into products (such as profiles, pipe, hose, sheet, film or bottles) and in the coating of wires, cables, paper, board or foil. A major reason for its use is the screw extruder's ability to melt efficiently and pump continuously large amounts of plastics materials. The understanding of the melting/pumping operation of the extruder and the development of larger and faster-running machines so as to give higher outputs have been given great attention and the results have been widely published. However, the whole manufacturing technology for extruded products has also developed, particularly in recent years. This has occurred not only by the use of modern screw extruders, but also by the incorporation of improved process control systems, the better design of dies and extrudate handling machinery and by the utilisation of improved plastics materials and additives. It is the purpose of this book to present selected topics which contribute to, or exemplify, these developments in extrusion-based processes.

In order to make the subject manageable the term 'injection moulding' has been restricted in its use so that only those processes which rely on thermal softening of the polymeric materials have been described and discussed in this book. It is intended to discuss the subject of reaction injection moulding in a separate book. However, even with this omission, the subject is still a very large one as nowadays many sorts or types of polymers are injection moulded. For example, it is estimated that one-third of all plastics materials are injection moulded-the range of products produced is enormous and increases daily. Because most moulding materials are based on plastics, in particular thermoplastics, the materials guides which form a large part of this book concentrate on the moulding of thermoplastics materials. Such guides should only be treated as general guidelines as each of the materials is normally available in a wide range of grades. These may differ in polymer molecular weight, molecular weight distribution, the additives used and their concentration, the physical form of the moulding compound, etc. A wide range of processing behaviours and end-use properties is therefore possible from any of the materials listed. This versatility is typified by the rubbery polymers which are compounded into an incredibly wide range of compounds. Because of this versatility only a very general guideline has been given for such materials.

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.

Injection moulding is the most important moulding process used by the plastics industry and some idea of its importance can be obtained by considering the following figures. The value of the UK market for plastics processing equipment was £60 million in 1977. Of this sum, £23 million was spent on injection moulding machines, that is, 40 % of all the money spent on plastics processing equipment in the UK. It has been estimated that one-third of all plastics materials are processed by injection moulding. At the present time the process is of greater importance to the thermoplastics industry but its relevance to the thermoset industry should not be ignored. Most ofthe equipment now used is based on single-screw pre-plasticising units. Once these machines had become established, in the 1960s, it was felt that the ultimate had been reached in machine design and utilisation. However, since that time, machines, processes and materials have undergone extensive development to make injection moulding safer, more reliable, easier to use and more economical to operate. The purpose ofthis book is to review some of the developments that have taken place in this very important area. These developments are described by specialists in the field, who have extensive industrial experience and whose contribution will therefore be of immediate relevance to those concerned with the usage and application of this, the most important plastics moulding process.

A comprehensive encyclopaedic dictionary on polymer technology with expanded entries - trade name and trade marks, list of abbreviations and property tables.

Because of the sheer size and scope of the plastics industry, the title Developments in Plastics Technology now covers an incredibly wide range of subjects or topics. No single volume can survey the whole field in any depth and what follows is, therefore, a series of chapters on selected topics. The topics were selected by us, the editors, because of their immediate relevance to the plastics industry. When one considers the advancements of the plastics processing machinery (in terms of its speed of operation and conciseness of control), it was felt that several chapters should be included which related to the types of control systems used and the correct usage of hydraulics. The importance of using cellular, rubber-modified and engineering-type plastics has had a major impact on the plastics industry and therefore a chapter on each of these subjects has been included. The two remaining chapters are on the characterisation and behaviour of polymer structures, both subjects again being of current academic or industrial interest. Each of the contributions was written by a specialist in that field and to them all, we, the editors, extend our heartfelt thanks, as writing a contribution for a book such as this, while doing a full-time job, is no easy task.

This volume, the fourth in a series which began in 1979, covers a greater variety of subjects than any previous single volume. The basis of selection has been topical interest; hence the tailor-making of polymers to develop specific properties, methods of improving com­ pound processability and the use of rubbers in the oil industry are featured alongside a discussion of safety aspects. We have again sought the cooperation of the foremost authorities on the chosen subjects and have been delighted at the response which has yielded a list of authors of international repute. A. w. K. S. L. CONTENTS Preface v List of Contributors ix 1. Recent Developments in Synthetic Rubbers by Anionic Polymerization 1 I. G. HARGIS, R. A. LIVIGNI and S. L. AGGARWAL 2. Advances in Nitrile Rubber (NBR) 57 P. W. MILNER 3. Epoxidized Natural Rubber. 87 C. S. L. BAKER and I. R. GELLING 4. Process Aids and Plasticizers . 119 B. G. CROWTHER 5. A Review of Elastomers Used for Oilfield Sealing Environments . 159 W. N. K. REVOLTA and G. C. SWEET 6. Using Modern Mill Room Equipment . 193 H. ELLWOOD 7. Quality Requirements and Rubber Mixing . 221 P. S. JOHNSON 8. Health and Safety . . 253 B. G. WILLOUGHBY Index . 307 vii LIST OF CONTRIBUTORS s. L. AGGARWAL Gen Corp , Research Division, 2990 Gilchrist Road, Akron, Ohio 44305, USA C. S. L. BAKER Malaysian Rubber Producers' Research Association, Tun Abdul Razak Laboratory, Brickendonbury, Hertford SG13 8NL, UK B. G.

Because of the sheer size of the plastics industry, the title Developments in Plastics Technology now covers an incredibly wide range of subjects or topics. No single volume can survey the whole field in any depth and so what follows is therefore a series of chapters on selected topics. The topics were selected by us, the editors, because of their immediate relevance to the plastics industry. When one considers the materials produced and used by the modern plastics industry, there is a tendency to think of the commodity thermoplastics (such as poly(vinyl chloride) or polyethylene); the thermosetting materials are largely ignored. Because of this attitude we are very pleased to include in this volume a chapter which deals with the processing of a thermosetting material, i.e. the pultrusion of glass reinforced polyester. The extrusion of plastics is, of course, a very important subject but an aspect which is often overlooked is the need to remove volatile matter during processing: for this reason we have included a chapter on devolatilisation. Current industrial practice is towards materials modification and this attitude is reflected in the chapters on the transformation of ethylene vinyl acetate polymers and the use of wollastonite in two important thermoplastics. When assessing the performance of materials, there is a tendency to concentrate on short-term mechanical tests and ignore such topics as fatigue and longer-term testing. We are therefore very pleased to include a chapter on this subject.