Antioxidant Polymers

Antioxidant Polymers is an exhaustive overview of the recent developments in the field of polymeric materials showing antioxidant properties. This research area has grown rapidly in the last decade because antioxidant polymers have wide industry applications ranging from materials science to biomedical, pharmaceuticals and cosmetics.

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.

Handbook of Antioxidants provides a wealth of information on the mechanics, practical effects and applications of a wide range of antioxidants. The book starts by introducing the general concepts relating to antioxidants and their application, then segues into a discussion on existing natural and synthetic antioxidants, characterizing their general properties and application. Formation and action of oxidizing species in living organisms, ambient air, industrial environments, and chemical reactions are covered next. Subsequent chapters cover the theories and mechanisms of stabilization, performance indicators, antioxidant selection, degradation and stabilization of different polymers and rubbers, specific effects on other components of formulation, and analytical methods. This book is an excellent companion to the Databook of Antioxidants which has also been published recently. Both books supplement each other without repeating the same information – one contains data another theory, mechanisms of action, practical effects and implications of application. Provides theory, mechanisms of action, practical effects and implications of application for an array of antioxidants Looks at different aspects of phenomena occurring when materials are exposed to ambient air which contains oxygen, ozone, singlet oxygen, and other oxidizing species (radicals) Covers natural and synthetic antioxidants, their stability, performance indicators, degradation and stabilization mechanics, and more

Polymers are an important part in everyday life; products made from polymers range from sophisticated articles, such as biomaterials, to aerospace materials. One of the reasons for the great popularity exhibited by polymers is their ease of processing. Polymer properties can be tailored to meet specific needs by varying the “atomic composition” of the repeat structure, by varying molecular weight and by the incorporation (via covalent and non-covalent interactions) of an enormous range of compounds to impart specific activities. In food science, the use of polymeric materials is widely explored, from both an engineering and a nutraceutical point of view. Regarding the engineering application, researchers have discovered the most suitable materials for intelligent packaging which preserves the food quality and prolongs the shelf-life of the products. Furthermore, in agriculture, specific functionalized polymers are used to increase the efficiency of treatments and reduce the environmental pollution. In the nutraceutical field, because consumers are increasingly conscious of the relationship between diet and health, the consumption of high quality foods has been growing continuously. Different compounds (e.g. high quality proteins, lipids and polysaccharides) are well known to contribute to the enhancement of human health by different mechanisms, reducing the risk of cardiovascular disease, coronary disease, and hypertension. This second volume focuses on the importance of polymers and functional food and in food processing

Databook of Antioxidants is divided into five sections covering general information, physical properties, health and safety considerations, ecological properties and the use and performance of each featured antioxidant. A general information section includes CAS #, common name/synonym, acronym, chemical category, moisture content, and more. The physical properties section features data on state, odor, color (Gardner and Platinum-cobalt scales), acid number, ash contents, and other characteristics. The health and safety section displays data on flashpoint, autoignition temperatures, explosive LEL and UEL, NFPA flammability and reactivity, ingestion, first aid, and beyond. The ecological properties portion of the book contains data on biodegradation probability, aquatic toxicity LC50, and partition coefficients, and the book concludes with a chapter on use and performance considerations with information on manufacturer, outstanding properties, typical applications, recommended dosage, concentration used, food approval, and more. This book is an excellent companion to the Handbook of Antioxidants which has also been published recently. Both books supplement each other without repeating the same information – one contains data another theory, mechanisms of action, practical effects and implications of application. Contains information on each antioxidant that is broken into five sections: General Information, Physical Properties, Health and Safety, Ecological Properties and Use and Performance Includes an introductory chapter in which general indicators of performance are discussed Features a chapter with information on the data fields included in the description of individual stabilizers

This report describes the theory of weathering and its effect on polymer properties, methods of stabilisation, and natural and accelerated weathering tests. The problems associated with particular polymers used in outdoor applications are explained. An additional indexed section containing several hundred abstracts from the Rapra Polymer Library database provides useful references for further reading.

Polymers play a vital role in manufacturing processes of many kinds, and the development of new polymeric materials is of increasing importance in the field of materials science. Because of this, there is a need to understand why the properties of polymers change, what can be done to avoid degradation and failure, and how performance can be maintained over a much longer lifespan. The authors deal firstly with the process of degradation through oxidation, and then explain how the addition of various antioxidants can inhibit or retard this process. They present a unique discussion of the physico-chemical aspects, particularly the chemical kinetics of antioxidant action and of branched chain reaction kinetics, and the theory of critical phenomena inhibited oxidation. The last part of the book offers practical advice on methods of oxidation investigation, on selection of appropriate antixodants, and on the basic principles of performance prognosis. The book also includes a unique coverage of the regularities of additive solubility.

Chemical modification of polymers by reactive modifiers is no longer an academic curiosity but a commercial reality that has delivered a diverse range of speciality materials for niche markets: reactively grafted styrenic alloys, maleated polyolefins, super-tough nylons, silane modified and moisture-cured polyolefins, and thermoplastic elastomers, are but few exam ples of commercial successes. Although the approach of reactive modification of polymers has been largely achieved either in solution or in the solid state (through in situ reactions in polymer melts), it is the latter route that has attracted most attention in the last two decades owing to its flexibility and cost-effective ness. This route, referred to as reactive processing, focuses on the use of suitable reactive modifier(s) and the adoption of conventional polymer processing machinery, an extruder or a mixer, as a chemical reactor, to perform in situ targeted reactions for chemical modification of preformed polymers. This relatively simple, though scientifically highly challenging, approach to reactive modification offers unique opportunities in exploiting various reactive modifiers for the purpose of altering and transforming in a controlled manner the properties of preformed commercial polymers into new/speciality materials with tailor-made properties and custom-designed performance for target applications. Such an economically attractive route constitutes a radical diversion away from the traditional practices of manufacturing new polymers from monomers which involves massive in vestments in sophisticated technologies and chemical plants.