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.

The emergence of reaction injection molding (RIM) has been fol lowed by the industry with mounting interest. RIM technology has brought to polymer processing a new flexibility and savings in both energy and capital investment. The new developments and the number of engineers and scientists working in RIM is growing at so fast a rate that there is need for sharing information on progress in this area. This book is based on papers presented at the International Symposium on Reaction Injection Molding which was held in 1981 in Atlanta, Georgia, and was sponsored by the American Chemical Society, Division of Organic Coatings and Plastics Chemistry. The book is divided into four parts covering different areas of RIM development. The first part is devoted to the future trends of RIM develop ment in the United States and Japan. The structure-properties relationship and effects of annealing on properties of RIM elastomers are covered in the second part. New non-urethane polymers such as polyamides, polyisocyanurates and polystyrene suitable for RIM processing are discussed in the third part. In the last part the engineering and technological aspects of RIM, such as glass reinforcement, mixing, flow and moldability are covered in detail. Finally I would like to thank Mrs. Iris Glebe for typing this book and for help with editing, and K. Zielinski for his assistance v vi PREFACE in reviewing and, when necessary, correcting some of the papers. Thanks is also due to the editors of Plenum for their patience and helpfulness.

Polymers are ubiquitous and pervasive in industry, science, and technology. These giant molecules have great significance not only in terms of products such as plastics, films, elastomers, fibers, adhesives, and coatings but also less ob viously though none the less importantly in many leading industries (aerospace, electronics, automotive, biomedical, etc.). Well over half the chemists and chem ical engineers who graduate in the United States will at some time work in the polymer industries. If the professionals working with polymers in the other in dustries are taken into account, the overall number swells to a much greater total. It is obvious that knowledge and understanding of polymers is essential for any engineer or scientist whose professional activities involve them with these macromolecules. Not too long ago, formal education relating to polymers was very limited, indeed, almost nonexistent. Speaking from a personal viewpoint, I can recall my first job after completing my Ph.D. The job with E.I. Du Pont de Nemours dealt with polymers, an area in which I had no university training. There were no courses in polymers offered at my alma mater. My experience, incidentally, was the rule and not the exception.

Provides reference information concerning the injection molding operation and each of its aspects. It examines considerable technological advancements, especially those in computer methods, that have been made since the second edition was published.