Poly o-acetylstyrene

During UV irradiation ( 300 nm) of poly(o-acetylstyrene) (3.23) two primary processes occur [2261, 2263]  

Photophysical process which involves photoisomerization and the forma- 

This mechanism agrees with the primary step in the photoisomerization of both low and high molecular weight o-alkyl ketones, which involves intramolecular hydrogen abstraction by the n-m triplet to form the biradical, which in turn rearranges into the enol [197, 198, 1060, 2200, 2201]. 

Photochemical process which occurs via the Norrish Type I reactions (cf. section 3.2.1)  

These two primary photoprocesses are accompanied by secondary reactions of the initially formed radicals, i.e. dissociation, abstraction and addition (crosslinking). 

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Photodegradation of poly(o-propionylstyrene) (3.24) occurs by the same mechanisms as photodegradation of poly(o-acetylstyrenes) (cf. section 3.2.9) [2235]. 

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