Studies on the Oxidation of High Polymers

VI. Oxidation of Polyethylene by the γ-Ray Irradiation

Abstract

It is well known that polyethylene is oxidized in air by γ-ray irradiation at the room temperature. But its oxidation mechanisms have not been elucidated in detail. Therefore, we measured the oxygen absorption with time under the various γ-ray intensities, and studied its oxidation mechanisms. The rates of oxidation increased autocatalitically with its oxygen absorption and then reached maximum values. It is concluded that γ-ray oxidations include apparent radical chain reactions. The oxygen absorption was more effective at weaker intensities than stronger intensities. Moreover, the flow points of the irradiated samples have not practically increased under the irradiation of more than 20 Mrep, and cross-links have not been almost produced.