Alterung von copolymeren, die ketogruppen enthalten†

Polymers of polystyrene and polyoelefine, containing covalently linked keto groups, are obtained. Polystyrene polymers are prepared by polymerization of styrene and unsatured ketones in the presence of polybutadiene while polyolefines are obtained by grafting unsatured ketones to the polymer. Films of copolymers, thus prepared, undergo photochemical degradation when exposed to natural and artificial light. The rate of degradation is considerably higher, as compared to the analogical polymers without keto groups, and it depends on the type and concentration of the ketone used. The reaction of degradation is propably mainly Norish II-type which has the effect of decreasing the molecular weight of copolymers. That assumption is confirmed by the observed alteration in carbonyl and hydroxyl range - 1720 cm−1 and 3450 cm−1 respectively in the polymer chains when they are irradiated.