Abstract
The photochemistry of poly( p-hydroxystyrene) (PPHS) has been investigated, thin films being exposed to 254 nm radiation under high vacuum at 298K. H 2 is the principal volatile product, but small amounts of H 2O are also formed. The polymer becomes rapidly coloured, but unlike other styrene polymers, which remain yellow, PPHS undergoes a progressive colour change from yellow through orange to brown. Infrared spectral data indicate the depletion of OH group concentration, and a concomitant formation of carbonyl, possibly quinonoid species. Crosslinking is rapid and no chain scission was detected. It is likely that the polymeric phenoxy radicals formed by photolysis or by subsequent H-abstraction contribute to the formation of both quinonoid species and crosslinks. The mechanism of the photolysis is discussed.
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