Photodegradation and Photooxidation of Polymers

Photodegradation and Photooxidation of Polymers Several reviews have appeared covering general as well as specific 

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These materials, the polymeric sulphones, also come into the category of hexavalent sulphur compounds and are derivatives of sulphonic acids. The photochemistry and the radiation chemistry of these substances have been reviewed in a variety of texts. Thus the radiation chemistry was reviewed in considerable detail in 1988147. Other texts have reviewed photodegradation and photooxidation of polymers in general with some reference to the polysulphones149. It appears that polysulphones have low thermal stability and as a result have failed to undergo commercial utilization149. 

C. Decker, K. Zahouily, Photodegradation and photooxidation of thermoset and UV-cured acrylate polymers , Polym. Degr. Stab., 1999, 64, 293-304. 

B. Ranby and J.F. Rabek, Photodegradation, Photooxidation and Photostabilization of Polymers,... 

Ranby, B. Rabek, J. F., "Photodegradation, Photooxidation and Photostabilization of Polymers", John Wiley Sons, New York, 1975. 

On the more commercial front, the photooxidation of polymers continues to attract attention with a continued special interest in natural materials. Bio- and photodegradable plastics are important for agricultural usage. The same applies to polymer stabilisation where commercial applications dominate significantly with much emphasis on the synergistic behaviour of stabilisers. For dyes and pigments stability continues to be of major concern. 

Since 1971 our department is Involved in study of photodegradation, sensitized photooxidation and photostabilization of polymers. A big effort is made in the study of singlet oxygen oxidation of several important polymers, such as polydienes, poly(vinyl chloride), polystyrene and polyesters, reactions of atomic oxygen and ozone with polydienes and photostabilization of these polymers. 

Our interest in polymer photodegradation has led us to an investigation of the competition for migrating energy by chain impurities and "defects" such as excimer-forming sites. To isolate the intrachain phenomena, photooxidation of polymer solutions in dimethoxymethane have been carried out. As an example of a very photostable excimer-forming polymer, PS has been selected. Since poly(methyl methacrylate) (PMMA) is known to be far less stable than PS on a quanta-absorbed basis, MMA units have been incorporated into the chain to act as weak links. For energy sinks, 1-VN and 2-VN units have been made part of the chain. 

Ranby, B., and Rabek, J. F. Photodegradation, photooxidation and photostabilization of polymers. Sect. 4.1.1.2. New York Wiley Sons 1975. 

The photooxidation of polymers on the other hand eontinues to remain at a low profile. Bio- and photodegradable plasties continue to be useful for agricultural usage, although interest here is again minimal. The same applies to polymer photostabilization, where eommercial applieations dominate very much, with emphasis on the practical use of stabilizers. For dyes and pigments, stability continues to be a major issue in so far as this seetion is concerned. 

B. Ranby, F. J. Rabek Photodegradation, Photooxidation and Photostabilisation of Polymers. J. Wiley Sons, London 1975. 

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