SPIN-LABELING OF DEGRADED POLYPROPYLENE .1. FORMATION OF OXAZOLIDINE NITROXIDE

The kinetics of nitroxide formation on a polypropylene (PP) chain by r eaction between carbonyl groups of gamma-irradiated PP and 2-amino-2-m ethyl-1-propanol has been studied, During the reaction the total conce ntration of carbonyl and amine groups passes through a maximum. At the end of the reaction a weak ESR signal due to nitroxide groups was det ected and its intensity was strongly enhanced by peroxidation with m-c hloroperbenzoic acid. The presence of nitroxides after the reaction wi th the aminoalcohol has been explained by the interaction of an oxazol idine moiety with singlet oxygen coming from the decomposition of PP-h ydroperoxides or by reaction of the latter compounds with the oxazolid ine nucleus.