| Abstract: | A study has been made of the diffusion, solubility, and separation of nitrogen and methane gases in a series of air-and vacuum-irradiated polyethylene films in the temperature range of 15° to 50°C. Samples were air irradiated to 90 Mrads and vacuum irradiated to 80 Mrads. The major structural differences between the modified films were the presence of oxygenated species in the air-irradiated samples. The oxidation of these samples reduced the amount of crosslinking normally found in vacuum-irradiated samples. Diffusion and permeability coefficients for both gases decreased with irradiation dose. The solubility coefficients for the air-irradiated samples increased with increasing irradiation dose while little change was observed for vacuum-irradiated film. The gas mixture permeabilities could be predicted from the pure component permeabilities, and the methane–nitrogen separation factor decreased with increasing irradiation dose. |
