SECONDARY AND TERTIARY PIPERIDINYL COMPOUNDS AS STABILIZERS FOR GAMMA-IRRADIATED POLYPROPYLENE

The effects of sec. and ter. piperidinyl additives on oxidative resist ance of gamma-irradiated polypropylene have been studied over a quite wide range of additive concentrations. Tert. amines were the more effe ctive in suppressing oxidation during the gamma-irradiation step. All piperidinyl compounds gave a product identified by IR as a ring-opened nitro compound as well as nitroxides. From the dependence of nitroxid e and nitro-compound on the initial concentration of the tert. piperid inyl compounds, an amine oxide is proposed as the transient intermedia te leading to nitro-formation from the tert.-piperidinyl additives.