Degradation and Stabilisation of PVC


Book Description

Polyvinyl chloride has played a key role in the development of the plastics industry over the past 40 years and continues to be a polymer of major importance. The reasons for its enormous versatility and range of application derive from a combination of the basic structure which gives rise to a relatively tough and rigid material and its ability to accept a range of plasticisers and other additives which can modify its physical characteristics to produce a range of flexible products. Two major problems, however, have tested the skill and ingenuity of PVC technologists since earliest times. One is the thermal instability of the material at the temperatures required for melt processing and fabrication, and the second is the photochemical instability which until recently has limited the potentially large range of outdoor applications. Both problems have been handled in a commercially satisfactory way by the gradual development of a range of stabilisers, lubricants and other processing aids and the high quality material which has resulted has led to massive utilisation of PVC by industry. Totally adequate stabilisation requires a detailed understanding of the mechanisms by which degradation processes are initiated and propagated. Although great advances have been made in this respect in recent years the problem remains incompletely understood. This book presents an account of the present position and the problems which remain to be solved.




Degradation and Stabilisation of PVC


Book Description

Polyvinyl chloride has played a key role in the development of the plastics industry over the past 40 years and continues to be a polymer of major importance. The reasons for its enormous versatility and range of application derive from a combination of the basic structure which gives rise to a relatively tough and rigid material and its ability to accept a range of plasticisers and other additives which can modify its physical characteristics to produce a range of flexible products. Two major problems, however, have tested the skill and ingenuity of PVC technologists since earliest times. One is the thermal instability of the material at the temperatures required for melt processing and fabrication, and the second is the photochemical instability which until recently has limited the potentially large range of outdoor applications. Both problems have been handled in a commercially satisfactory way by the gradual development of a range of stabilisers, lubricants and other processing aids and the high quality material which has resulted has led to massive utilisation of PVC by industry. Totally adequate stabilisation requires a detailed understanding of the mechanisms by which degradation processes are initiated and propagated. Although great advances have been made in this respect in recent years the problem remains incompletely understood. This book presents an account of the present position and the problems which remain to be solved.




Photostabilization of Polymers


Book Description

During the last two decades, the production of polymers and plastics has been increasing rapidly. In spite of developing new polymers and polymeric materials, only 40-60 are used commercially on a large scale. It has been estimated that half of the annual production of polymers is employed outdoors. Increasing the stability of polymers and plastics towards heat, light, atmospheric oxygen and other environmental agents and weathering conditions has always been a very important problem. The photochemical instability of most of polymers limits them to outdoor application, where they are photo degraded fast over periods ranging from months to a few years. To the despair of technologists and consumers alike, photodegrada tion and environmental ageing of polymers occur much faster than can be expected from knowledge collected in laboratories. In many cases, improved methods of preparation and purification of both monomers and polymers yield products of better quality and higher resistance to heat and light. However, without stabilization of polymers by applica tion of antioxidants (to decrease thermal oxidative degradation) and photostabilizers (to decrease photo-oxidative degradation) it would be impossible to employ polymers and plastics in everyday use.




Chemistry of Chlorine-containing Polymers


Book Description

Chemistry of Chlorine-Containing Polymers - Syntheses, Degradation, Stabilization




PVC Handbook


Book Description

In this single handbook, the editors aim to give a diverse audience of readers a complete account of all aspects of PVC--from monomer manufacture to polymerization; the gamut of such additives as stabilizers, lubricants, plasticizers, impact modifiers, fillers and reinforcing agents; blends and alloys; compounding and processing; characterization; combustion resistance and weatherability; product engineering design; applications; environmental and safety; and finally the PVC industry dynamics. This handbook contains both practical formulation information as well as a mechanistic view of why PVC behaves as it does.




Physical Properties of Polymers


Book Description

The contents have been divided into sections on physical states of polymers and characterization techniques. Chapters on physical states include discussions of the rubber elastic state, the glassy state, melts and concentrated solutions, the crystalline state, and the mesomorphic state. Characterization techniques described are molecular spectroscopy and scattering techniques.




Thermal Degradation of Polymeric Materials


Book Description

Understanding the thermal degradation of polymers is of paramount importance for developing a rational technology of polymer processing and higher-temperature applications. Controlling degradation requires understanding of many different phenomena, including chemical mechanisms, the influence of polymer morphology, the complexities of oxidation chemistry, and the effects of stabilisers, fillers and other additives. This book offers a wealth of information for polymer researchers and processors requiring an understanding of the implications of thermal degradation on material and product performance.




Precision Process Technology


Book Description

New process technology strategies are required to cope with the future. Fossil feedstocks are losing ground in favour of renewable feedstocks and secondary resources. Conventional processing routes using thermal `sledgehammer' techniques are replaced by highly selective (bio)catalytic conversions. The future process engineer is neither allowed to think in terms of unit operations, nor to take for granted the conventional practice of continuous steady state processing. Hybrid systems and transient operations are more and more frequently encountered. The continuing impressive progress being made in process modelling and control will revolutionize the process industries. In the new generation of chemical production processes the keyword is precision. Precision in terms of selectivity and of efficiency, is required to maximize the utilisation of materials and energy. Moreover, enhanced precision is needed to exploit the quality of materials and energy to the full extent. Only by reducing the squandering of materials, energy and quality will a harmonious relationship be established between the process industries, the economy, and the environment. Process integration, as well as an integrated effort by the disciplines involved in process technology, will be of crucial importance in attaining the goals of precision process technology. These emerging strategies involve an active exchange of tools and ideas between a variety of disciplines, not only in plant design and operation, but even more in the early stages of process development and design. By looking from various angles at what the future has in store for the process industries, this volume systematically lifts the corners of the veil and may inspire to establish a new tradition of precision in process technology.




Marine Anthropogenic Litter


Book Description

This book describes how man-made litter, primarily plastic, has spread into the remotest parts of the oceans and covers all aspects of this pollution problem from the impacts on wildlife and human health to socio-economic and political issues. Marine litter is a prime threat to marine wildlife, habitats and food webs worldwide. The book illustrates how advanced technologies from deep-sea research, microbiology and mathematic modelling as well as classic beach litter counts by volunteers contributed to the broad awareness of marine litter as a problem of global significance. The authors summarise more than five decades of marine litter research, which receives growing attention after the recent discovery of great oceanic garbage patches and the ubiquity of microscopic plastic particles in marine organisms and habitats. In 16 chapters, authors from all over the world have created a universal view on the diverse field of marine litter pollution, the biological impacts, dedicated research activities, and the various national and international legislative efforts to combat this environmental problem. They recommend future research directions necessary for a comprehensive understanding of this environmental issue and the development of efficient management strategies. This book addresses scientists, and it provides a solid knowledge base for policy makers, NGOs, and the broader public.




Mechanisms of Polymer Degradation and Stabilisation


Book Description

The purpose of this publication is two-fold. In the first place it is intended to review progress in the development of practical stabilising systems for a wide range of polymers and applications. A complemen tary and ultimately more important objective is to accommodate these practical developments within the framework of antioxidant theory, since there can be little question that further major advances in the practice of stabilisation technology will only be possible on a firm mechanistic foundation. With the continual increase in the number of commercial anti oxidants and stabilisers, often functioning by mechanisms not even considered ten years ago, there is a need for a general theory which will allow the potential user to predict the performance of a particular antioxidant structure under specific practical conditions. Any such predictive tool must involve a simplified kinetic approach to inhibited oxidation and, in Chapter 1, Denisov outlines a possible mechanistic approach with the potential to predict the most useful antioxidant to use and the limits of its usefulness. In Chapter 2, Schwetlick reviews the current state of knowledge on the antioxidant mechanisms of the phosphite esters with particular emphasis on their catalytic peroxidolytic activity. Dithiophosphate v vi PREFACE derivatives show a similar behaviour but for quite different reasons and, in Chapter 3, AI-Malaika reviews information available from analytical studies, particularly using 31p_NMR spectroscopy, to elucid ate the complex chemistry that leads to the formation of the antioxidant -active agents.