Causes, Effects and Case Studies Involving Degradation
Plastics and rubbers together make up the most adaptable and varied class of materials available to product designers. They may be transparent or opaque, rigid or flexible, lightweight, insulating, and weatherproof. They are used in almost every industry, and in every part of the home. Applications range from the humble hot water bottle to the sheathing on a high voltage cable, and from a simple scrubbing brush to a tank for storing hydrochloric acid. Products may be disposable (e.g. packaging goods) or intended to last for decades, such as a buried sewage pipe. However, it is this very diversity which makes materials selection so difficult, and appropriate design so important. Indeed the one thing that all these particular products have in common is their presence in this book of failures. Failures due to degradation may result from exposure to the weather or an aggressive operating environment. Alternatively they may be caused by the introduction of an external agent unforeseen by the product designer. They may be rapid or very slow, and they may result from a combination of factors. In this book Dr. Wright describes the following mechanisms of polymer degradation, and then illustrates each failure mechanism with a number of case studies: Thermo-oxidation, Photo-oxidation, Degradation due to ionising radiation, Chemical attack, Environmental stress cracking, Other miscellaneous effects, including treeing, electrochemical degradation and biodegradation. Many of the case studies are based on Dr. Wrights own experiences whilst working at Rapra. In each case he describes the circumstances of the failure, and discusses both the consequences of the failure and the lessons that may be learned from it. Most of the failed products are familiar to us all, and his style is both readable and informative. Photographs are included where available. The book will be essential reading for designers, engineers, product specifiers and forensic engineers. Materials suppliers and processors will also benefit from the pragmatic analysis and advice it contains. It will also be of value to all students of polymer science and technology, providing an essential insight into the practical application of plastics and rubbers and the potential problems. Finally, it will be of interest to a much broader readership, including anyone who ever wondered why things break, and it should become a standard reference work in all technical libraries. This book was written with the support of the UK Department of Trade and Industry. It is intended to raise awareness of the causes and consequences of polymer product failures, in order to reduce the future incidences of such failures, and their considerable costs to industry.