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.

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.

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.

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.

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.

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.