Photodegradable plastic environment

Photodegradable plastics degrade after prolonged exposure to sunlight, so will not degrade if buried in a landfill, a compost heap, or other dark environment, or if heavily overprinted. Oxo-biodegradable... 

There is some debate as to whether photodegradable plastics are better for the environment or not. In a landfill site, the plastic waste is often buried under other rubbish and eventually soil - so there is no light available to trigger the breakdown of the polymer chains. They also make recycling plastics problematic, as they could weaken a recycled mixture of different plastics when it is put to a new use. 

The photolysis of copolymers containing ketone groups has both academic and practical interest since the way in which the polymeric environment affects the photochemical pathways leads to an understanding of the photodegradation of polymers in which the ketone group is present as an adventitious or intended impurity. Copolymers with vinyl ketones also provide a practical means for preparing plastics with controlled lifetimes as a means of combatting litter problems (1.-3). 

Discarded conventional plastics remain in the environment for decades. They block sewers and drains, disfigure the streets, beaches and countryside, and kill wildlife on land, in rivers and oceans. To overcome these problems increasing attention has been paid to the development of degradable plastics (1) starch-based, biodegradable, (2) aliphatic polyesters, biodegradable, (3) photodegradable, and (4) oxo-biodegradable. 

Andrady AL, Pegram JE, Nakatsuka S. Studies on controlled hfetime plastics. 1. The geographic variabihty in out-door lifetimes of enhanced photodegradable polyethylene. J Environ Polym Degrad 1993a l (1) 31. 

Andrady AL, Pegram JE. Smdies on enhanced degradable plastics II. Weathering of enhanced photodegradable polyethylenes under marine and freshwater floating exposure. J Environ Degrad 1993c l (2) 117-126. 

A.L. Andrady, J.E. Pegram, S. Nakatsuka, Studies on enhanced degradable plastics 1. The geographic variability in outdoor lifetimes of enhanced photodegradable polyethylenes. J. Environ. Polym. Degrad. 1, 31-43 (1993a)... 

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