Photodegradable plastic

Methyl vinyl ketone is used as a comonomer in photodegradable plastics, and is an intermediate in the synthesis of steroids and vitamin A. It is highly toxic and faciUties handling over a threshold of 100 lbs (45.5 kg) are subject to special OSHA documentation regulations (273). 

Photodegradable plastics Plastics designed to degrade under the influence of sunlight. 

To improve the performance of photodegradable plastics, it is necessary to understand the photochemical decomposition mechanisms so that appropriate features and properties can be incorporated into the polymers to make... 

Guillet, J. 1997. Environmental aspects of photodegradable plastics. Macromolecu-lar Symposia, 123 209-24. 

This Report follows the format of the previous one except that, commencing this year, the patents section will be omitted. Academic and industrial research in this field continues to be prolific, particularly in areas of photopolymerization such as electron beam curing and photoresists. Other areas, such as the photosensitized degradation of polymers for producing photodegradable plastics, have diminished to only a few articles, and consequently these will now be included in the section dealing with photo-oxidation and photodegradation. 

Poly(vinyl ketones) such as poly(ethylene-a//-carbon monoxide) CAS 111190-67-1, poly(methyl vinyl ketone) CAS 25038-87-3, and poly(methyl isopropenyl ketone) CAS 25988-32-3, also have practical applications. For example, poly(ethylene-a/f-carbon monoxide) is used in photodegradable plastics and in various copolymers. Several studies were reported regarding the thermal stability of these polymers. It has been shown that poly(ethylene-a/f-carbon monoxide) decomposes upon heating with chain scission generating small molecular weight alkenes and ketones. Some literature reports discussing the thermal decomposition of poly(vinyl ketones) are summarized in Table 6.5.5 [13]. 

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. 

Photodegradable plastics are those degradable plastics where primary mechanism of degradation is through the action of sunlight. 

ASTM D 5071 Practice for Exposure of Photodegradable Plastics in a Xenon-Arc Apparatus ... 

The procednre recommends three basic test cycles commonly nsed for xenon-arc exposnre of photodegradable plastics ... 

ASTM D 5208 Practice for Fluorescent Ultraviolet (UV) Exposure of Photodegradable Plastics ... 

This practice is technically equivalent to ASTM D 4329 (see above) that covers UV exposure of plastics intended for long-term use in outdoor applications. This procedure covers testing of photodegradable plastics intended to deteriorate rapidly when exposed to solar radiation, heat, moisture, and other degrading elements of the weather. 

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... 

Quantum Chemicals (natural and synthetic polymers, biodegradable and photodegradable plastics, and chromatography). 

Fragmentation (of photodegraded plastics) occurs without any fundamental... 

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