Photodegradable plastic polymers

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. 

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... 

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. 

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). 

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

The stability, very important from the industrial point of view, can be controlled by choice of kinds and quantities of various stabilizers. If 1, 2-PBD contains only thermal stabilizers, the polymer is deteriorated within a few months under outdoor exposure. Especially, in summer, the thin film is deteriorated within a few weeks. Thus, 1, 2-PBD is considered to be a photodegradable plastics. Fig. 8 shows the possibilities of its life control through the use of various stabilizers. 

The plastic waste products are subject to photodegradation, which causes the plastic waste products to degrade into small toxic plastic polymers. In the course of time, the plastic polymers are broken down into smaller and smaller pieces. However, the polymers do not decompose into materials found in nature. These small... 

Sunscreen agents, also known as UV filters, are used extensively in personal care products and also are present in a wide variety of industrial goods, such as textiles, paints, and plastics to prevent photodegradation of polymers and pigments [75]. However, recent concern has risen due to their potential for endocrine disruption and developmental toxicity [76,77],... 

Weatherability of polymers (plastic) can generally be defined as the ability to withstand complex and variable atmospheric conditions similar to those prevailing in nature [142, 544, 1127, 1863, 2298]. Several papers have been devoted to the study of photodegradation of polymers in environmental conditions (Table 10.27). 

This volume is an effort to integrate this vitally needed information on photodegradation of polymers in a single book written as a monograph of the subject. This book should be a useful aid to all people from the polymer and plastic industries, scientists involved in photodegradation studies and also to graduate or advanced undergraduate students. 

The first is to incorporate photosensitive groupings in the polymer backbone. The introduction of carbonyl, the product normally produced by hydroperoxide breakdown has been investigated by Guillet and his co-workers and some success has been reported. The same economic arguments apply to a tailor-made photodegradable plastics as applies to a biodegradable plastics that is, it will cost very much more than the common packaging materials. 

Gilead, D., 1995, Photodegradable Plastics in Agriculture. In Degradable Polymers Principles and Applications (G. Scott and D. Gilead, eds). Chapman Hall, London, pp. 186-199. 

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