Photodegradation of polymers

Most organic polymers undergo degradation when exposed to ultraviolet light. Radicals generated photochemically from carbonyl impurities in the polymer start the breakdown, followed by reaction of the radicals with oxygen from the atmosphere. 

Investigating Some Aspects of Photochemical Reaction Mechanisms 

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Multiphoton processes are also undoubtedly involved in the photodegradation of polymers in intense laser fields, eg, using excimer lasers (13). Moreover, multiphoton excitation during pumping can become a significant loss factor in operation of dye lasers (26,27). The photochemically reactive species may or may not be capable of absorption of the individual photons which cooperate to produce multiphoton excitation, but must be capable of utilising a quantum of energy equal to that of the combined photons. Multiphoton excitation thus may be viewed as an exception to the Bunsen-Roscoe law. 

J. E Rabek, Photodegradation of Polymers, Springer, Berlin Heidelberg New York (1996)... 

F. Photodegradation of polymers-. Photodegradation of polymers assumes importance in two different contexts (i) ultraviolet and visible radiations are harmful to biopolymers like DNA, polysaccharides, proteins, etc. and an understanding of their mode of photolysis is important in life processes and (ii) more and more use of plastic materials in everyday life has created a problem of disposal. 

J. D. Coyle. R. R. Hill and D. R. Roberts (eds), Light, Chemical Change and Life, Open University Press (1982). In this book are chapters on the photodegradation of polymers, photohalogena-tion, and the large-scale manufacture of caprolactam. 

Concentration versus time data for the photodegradation of polymer 7 as a function of irradiation time are shown in Figure 5.59 (The data in the figure were normalized by dividing the concentration values by the initial... 

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