Ketone group containing polymers

A more effective approach to enhancing the rate of photodegradation of PS is to copolymerize styrene with a small amount of a ketone-containing monomer. Thus the ketone groups are attached to the polymer during its manufacture (Pig. 13) (98,100). 

Poly(arylene ether ketone)s can also be modified by introducing the functional groups using similar approaches to polysulfones. For example, poly(arylene ether ketone)s were sulfonated.189 In addition, o-dibenzoylbenzene moieties in the poly(arylene ether)s can be transformed to heterocycles by cyclization with small molecules. These polymers can react with hydrazine monohydrate in the presence of a mild acid in chlorobenzene or with benzylamine in a basic medium.190 Another example of the use of the o-benzyl cyclization strategy is the intramolecular ring closure of poly(arylene ketone)s containing 2,2/-dibenzoylbiphenyl units to form poly(arylene ether phenanthrenes).191... 

As part of an effort to develop high-performance, high-temperature-resistant polymers for microelectronics applications, we also recently described a series of both partially fluorinated and nonfluorinated poly(aryl ether ketone)s containing amide, amide-imide, cyano oxadizole, or pyridazine groups and characterized their thermal and electrical properties.11... 

A similar variation in the quantum yield of the Norrish type I process is illustrated in Figure 3 for solid copolymers of ethylene containing three different ketone structures. The ketone groups in the backbone of the polymer chain in ethylene- copolymers show much lower quantum yields than those from the secondary or tertiary structures induced by copolymerization of methyl vinyl ketone and methyl isopropenyl ketone with ethylene. (See Table I, structures I, II and III.) In the latter two cases, the Norrish type I cleavage produces a small radical and a polymer radical, and it seems likely that the small radical has a much greater probability of escaping the cage than when the radicals produced are both polymeric, as in the case of structure I. 

With these many requirements, it is obvious that each group of polymers has its own plasticizers, although some types of plasticizers have been developed which are suitable for several plastics. They belong to the groups of esters, ketones, ethers, acetals, epoxides, and nitrogen containing compounds like the sulfonamides. 

One of the simplest polymers containing the ketone group can be synthesized by the high pressure copolymerization of ethylene and carbon monoxide ... 

In our early photochemical studies we have shown that the quantum efficiency for the type I processes in polymers containing ketone groups is highly sensitive to the location of the ketone group with respect to polymer chain, as shown in structures A and B below... 

Previous studies by Hartley and Guillet 0 and by Amerik and Guillet 0 have shown that polymers containing ketone groups undergo photolysis by the Norrlsh type I and type II reactions. The relative proportions of type I and H depend on the polymer concerned and the particular environment of the carbonyl group. These reactions are... 

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). 

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