It has become increasingly evident that there is much to begained from a detailed understanding of the structure and properties of polymers in the oriented state. This book reftects the growth of interest in this area of polymer scienceand attempts to give the reader an up to date viewofthe present position. The individual chapters are for the most part self contained, and cover a very wide range of topics. It is intended that each of them should serve the dual purpose of an expository introduction to the subject and a topical review of recent research. It is inevitable that there will be differences of style and approach in the contributions from the different authors. No atternpt has been made to moderate these differences, as they serve to illustrate the diversity of approaches required to give the reader a balanced view of the subject. I should like to thank the contributors for their endeavours, and especially for their patience in accepting modifications and corrections which make for consistency in the book as a whole. 1 am particularly indebted to Professor Leslie Holliday who originally approached me with the proposition that such a book would be a worthwhile venture and to the publishers who have given me every assistance in making its progress as painless as possible.

The last four years since the publication of the first of this series have seen further striking developments in both the science and technology of oriented polymers. In particular, polymers possessing very high degrees of molecular orientation are now quite commonplace, and this is reflected by the inclusion of five chapters dealing with ultra-high modulus polyethylene fibres, oriented liquid crystalline polymers (both lyotropics and thermo tropics) and polydiacetylene single crystal fibres. At the same time there is continuing interest in the structure and properties of less highly oriented polymers and in the mechanisms of deformation in polymers. It is therefore good to have these themes represented also. I should like to thank the contributors for adhering to a rather tight time schedule, and the publishers for their cooperation, so that this book can provide up-to-date reviews of the state of the art in a rapidly moving area of polymer science. I. M. WARD v CONTENTS Preface.... . . . .. . . . . .. ... . . . . . . . . . .. . . .. . . . . . . ... ... v List of Contributors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IX 1. Polymer Single Crystal Fibres ........................ .

It has become increasingly evident that there is much to begained from a detailed understanding of the structure and properties of polymers in the oriented state. This book reftects the growth of interest in this area of polymer scienceand attempts to give the reader an up to date viewofthe present position. The individual chapters are for the most part self contained, and cover a very wide range of topics. It is intended that each of them should serve the dual purpose of an expository introduction to the subject and a topical review of recent research. It is inevitable that there will be differences of style and approach in the contributions from the different authors. No atternpt has been made to moderate these differences, as they serve to illustrate the diversity of approaches required to give the reader a balanced view of the subject. I should like to thank the contributors for their endeavours, and especially for their patience in accepting modifications and corrections which make for consistency in the book as a whole. 1 am particularly indebted to Professor Leslie Holliday who originally approached me with the proposition that such a book would be a worthwhile venture and to the publishers who have given me every assistance in making its progress as painless as possible.

This new edition covers a range of topics including structure and morphology, mechanical properties, characterisation and experimental techniques. Each chapter provides an introduction to the subject as well as a topical review of recent research.

Treatise on Materials Science and Technology, Volume 10: Properties of Solid Polymeric Materials, Part A covers knowledge in the critical areas of polymeric materials. The book provides a background in polymer structure and morphogenesis, and discusses rubberlike elasticity, a phenomenon thermodynamically unique to long-chain polymers. The text also describes the mechanics of anisotropie, oriented polymeric systems and of glassy polymers. The fatigue behavior in solid polymers and the electrical properties of solid polymers are also reviewed. The book further tackles the electron processes and electrical breakdown in polymers. The text concludes with a discussion of the role of the environment on the integrity of polymeric solids. Materials scientists, materials engineers, and graduate students taking related courses will find the book useful.

Within the last two decades fracture theory has been one of the most rapidly advancing fields of continuous media mechanics. Noteworthy suc cess has been achieved in linear fracture mechanics where the propagation of the macrocrack in elastic materials is under study. However, fracture of materials is by no means a simple process since it involves fracture of structural elements ranging from atomic sizes to macrocracks. To obtain all information about how and why materials fail, all stages of the process must be studied. For a long time both mechanical engineers and physicists have been concerned with the problem of the fracture of solids. Unfortunately, most of their work has been independent of the others. To solve the problem not only requires the minds and work of mechanical engineers and physicists but chemists and other specialists must be consulted as well. In this book we will consider some conclusions of the "physical" and "mechanical" schools acquired by the A. F. Joffe Physics-Technical Institute of the USSR Academy of Sciences in Leningrad and the Institute of Polymer Mechanics of Latvian SSR Academy of Sciences in Riga. The methods for studying the phenomena of fracture applied at both Institutes are different yet complimentary to one another; the materials tested are also sometimes different.