DEGRADATION AND AGEING OF POLYMERS

Contents 1. Introduction, Historical Overview and Terminology Associated with the Degradation and Ageing of Polymers 452... 

TERMINOLOGY ASSOCIATED WITH THE DEGRADATION AND AGEING OF POLYMERS... 

Summing up the results obtained in the investigations of the catalytic activity of metals on the oxidation process in polymers it may be said that this activity plays a highly important role in the degradation and ageing of polymers. 

Rychly, J. and Strlic, M. (2005). Degradation and ageing of polymers. In Ageing and Stabilisation of Paper (M. Strlic and J. Kolar, eds) pp. 9-23. National and University Library, Ljubljana, Slovenia. 

Pospisil, J., Horak, Z., Krulis, Z Nespurek, S., and Kuroda, S.-i. (1999) Degradation and aging of polymer blends I. Thermomechanical and thermal degradation. Polym. Degrad. Stabil., 65, 405 14. 

Abstract The chemical and biochemical degradation and calcification are investigated as processes that alter the physical and mechanical properties of implanted polymers. The principles of oxidative, hydrolytic and enzymatic degradation and calcification of polymers in the body are discussed and the natural ageing of polymers in vivo and in vitro and the accelerated ageing of polymers are examined. The use of accelerated ageng is described as a method to predict changes in the physical and mechanical properties of polymers in vivo. 

For processing stabilization, Cytec s Cyanox phenolic antioxidants and phenolic phosphite blends offer excellent protection against thermo-oxldatlve degradation and discoloration of polymers. The Cyanox thloester antioxidants are efficient synergists used in phenolic antioxidant polymer applications reguiring good thermal aging properties. 

Environmental Impact of Ambient Ozone. Ozone can be toxic to plants, animals, and fish. The lethal dose, LD q, for albino mice is 3.8 ppmv for a 4-h exposure (156) the 96-h LC q for striped bass, channel catfish, and rainbow trout is 80, 30, and 9.3 ppb, respectively. Small, natural, and anthropogenic atmospheric ozone concentrations can increase the weathering and aging of materials such as plastics, paint, textiles, and mbber. For example, mbber is degraded by reaction of ozone with carbon—carbon double bonds of the mbber polymer, requiring the addition of aromatic amines as ozone scavengers (see Antioxidants Antiozonants). An ozone decomposing polymer (noXon) has been developed that destroys ozone in air or water (157). 

Jha, A. and Bhowmick, A.K., Thermal degradation and ageing behaviour of novel thermoplastic elastomeric nylon-6/acrylate rubber reactive blends, Polym. Degrad. Stab., 62, 575, 1998. 

Zou X, Gurnagul N. Uesaka T and Bouchard J (1994), Accelarated aging of papers of pure cellulose, mechanism of cellulose degradation and paper embritlement . Polymer Degradation and Stabilization, 43(3), 393 02. 

Kozlov, G. V. Shustov, G. B. Zaikov, G. E. The structural aspect of the interrelation of the characteristics of thermal and thermooxidative degradation of heterochain polyethers. In book Aging of Polymers, Polymer Blends and Polymer Composites. V. 2. Ed. Zaikov, G. Buchachenko, A. Ivanov, V New York, Nova Science Ihiblishers, Inc. 2002,151-160. 

In this chapter the basic features of polymers and their additives are introduced. The main ageing and degradation phenomena, which relate to the reliability and durability of polymers, from manufacture and service, to final disposal or recovery, are reviewed. The prediction of the long-term performance of polymers is discussed. 

A wide variety of characterisation methods is available for analysing polymer structure and properties [1-5]. Some of the most frequently-used are listed in Table 2.2, with examples of the information they provide, especially in respect to polymer degradation and ageing. 

M. B. Neiman, Aging and Stabilization of Polymers, Consultants Bureau, New York, 1965. S. H. Pinner, Weathering and Degradation of Plastics, Columbine Press, Manchester, 1966. J. Voigt, Die Stabilisierung der Kunststoffe gegen Ucht und Wdrme, Springer, Berlin, 1967. D. V. Rosato and R. T. Schwartz, Environmental Effects on Polymeric Materials, Interscience, New York, 1968. 

Chap. 7, Rheology of Polymer Alloys and Blends Chap. 9, Compounding Polymer Blends Chaps. 13, Physical Aging of Polymer Blends and 14, Degradation, Stabilization, and Hammability of Polymer Blends and... 

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