Abstract
Degradation of poly (vinyl alcohol) (PVA) under radio-irradiation in air was investigated to see whether the resulting carbonyl groups were produced by chain scission or by chemical reactions in main chain. The irradiation of PVA in power increased terminal carbonyl and keto type of carbonyl in main chain whereas the increase in the amount of carboxyl group was small. The scission took place via the oxidative intermediate, ketocarbonyl in the main chain, or via a pathway involving no oxidative, reaction. In the irradiation of PVA in aqueous solution, the degree of polymerization and the carbonyl content of PVA increase, where the carbonyl groups were dominantly formed in the main chain.
