Effect of atmosphere on radiation-induced crosslinking of polyethylene. Part I. Depressive effect and accelerating effect

Abstract

Polyethylene films were irradiated in various atmospheres by gamma-rays from a Co⁶⁰ source, and solubility measurements against xylene were carried out at 80°C. In NO₂ and O₂, the crosslinking of polyethylene is depressed markedly but in NH₃, Cl₂, and SO₂ not so much. On the other hand, N₂O accelerates the crosslinking appreciably. In CO and H₂, neither the depressive nor the accelerating effect is observed within a limit of error. In O₂, the depressive effect is more considerable at higher gas pressure and at lower dose rate; however, in N₂O the accelerating effect is reduced at higher gas pressure, and shows dose-rate independence within the range of our experiments.