The combined effects of oxidising media and heat result in degradation by thermo-oxidation. The principles and cases described in this review emphasise long term degradation in service. Two additional phenomena that influence thermo-oxidation are also described: catalysis by certain metal ions, and the influence of stress. An additional indexed section containing several hundred abstracts from the Polymer Library gives useful references for further reading.
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
The exposure of polymer surfaces to a combination of sun or artificial light, plus oxygen or other oxidising media induces degradation via photo-oxidation. Stabilisation methods described include the use of antioxidants, UV absorbers and light screens, quenchers, and radical scavengers and traps. An additional indexed section containing several hundred abstracts from the Polymer Library gives useful references for further reading.
Degradation reactions grouped under the heading chemical attack include oxidation hydrolysis, halogenation and other reactions. They also include some purely physical interactions between materials and fluids, dominated by the absorption of fluid into the material or vice versa. One particular mechanism described in some detail is acid induced stress corrosion cracking, which is the most frequent cause of premature failure of GRP products, and where the principle degradation reaction is between the fluid and the glass fibres. An additional indexed section containing several hundred abstracts from the Rapra Polymer Library database gives useful references for further reading.
To identify the specific features of the kinetics of oxidation of polymer mixtures, determine the key structural elements, and create a model that can describe the mechanism of thermal oxidation of polymer mixtures, it is necessary to determine the relation between the initial structure of a polymer mixture, structural rearrangements associated with oxidation and the kinetics of the process. The aim of this book is to elucidate the complicated problem concerning the connection between the structure and mechanism of oxidation of heterogeneous and heterophase polymer systems. The material presented in this book concerns the specific features of the kinetics of oxidation and those of the structure of polymer systems. The book deals with an analysis of the key factors that can affect principally the mechanism of thermal oxidation of polymer mixtures, determines the role of the phase morphology, structure of components, and the interface layer (or boundary) in the kinetics of oxidation of heterophase system by an example of mixtures of polyolefines. Along with the kinetics of oxidation of heterophase systems, problems of investigation of their structural parameters in the oxidized state are considered. With this aim, the material presented in the book concerns not only the mechanism of oxidation of polymer mixtures but also homopolymers of diverse morphology and model systems.
A comprehensive, practical guide to wood-plastic composites and their properties This is the first book that presents an overview of the main principles underlying the composition of wood-plastic composite (WPC) materials and their performance in the real world. Focusing on the characteristics of WPC materials rather than their manufacture, this guide bridges the gap between laboratory-based research and testing and the properties WPC materials exhibit when they're used in decks, railing systems, fences, and other common applications. Complete with practical examples and case studies, this guide: Describes compositions of WPC materials, including thermoplastics, cellulose fiber, minerals, additives, and their properties Covers mechanical properties, microbial resistance, water absorption, flammability, slip resistance, thermal expansion-contraction, sensitivity to oxidation and solar radiation, and rheological properties of hot melts of WPC Covers subjects that determine esthetics, properties, performance, and durability of wood-plastic composite products Includes comparisons of different ASTM methods and procedures that apply to specific properties This is a comprehensive, hands-on reference for scientists, engineers, and researchers working with wood-plastic composites in plastics and polymers, materials science, microbiology, rheology, plastic technology, and chemical engineering, as well as an outstanding text for graduate students in these disciplines. It's also an excellent resource for suppliers and WPC manufacturers, and an accessible guide for developers, homebuilders, and landscape architects who want to know more about wood-plastic composites and their performance in the real world.
The oxidative and thermal degradation of polymers has very important implications on their suitability for particular end-user applications. Particularly in relation to their physical properties and the lifetime over which the manufactured article retains these properties, after which they become unsuitable for purpose. Particular applications which come to mind are critical applications of polymers to the manufacture of electronic components and the design of polymeric alloys for aircraft fuselage assembly which retain their properties for many years over which the alloy must retain the physical properties at high or low operating temperatures. A particular area of growing importance is the recycling of manufactured components for re-use. Here, the polymer must retain its thermo oxidative resistance properties over a number of remouldings. A wide and increasing range of types of polymers are being used in these critical applications and an understanding of thermo oxidative processes will be very important in developing new applications in the future. This book brings together information on the thermooxidative resistance of polymers to change during processing and end-use life. Our present understanding of the chemical changes of the polymer that accompany degradation are also reviewed and the analytical methods by which changes can be ascertained are also discussed. This book will be of interest to those involved in the investigation of polymer stability and studies of the mechanics of polymer degradation, to polymer manufacturers and those who use polymers to manufacture end-use articles. This book will also be of interest to those involved in the manufacture of stabilisers for oxidation resistance for use in polymer manufacture, mechanical engineers and designers of polymer products.
