The permeability of some graft copolymers of polyethylene to gases and vapors

Abstract

AbstractGraft copolymers of polyethylene were prepared by gamma irradiation of polyethylene films immersed in the appropriate monomer. The majority of gas permeability measurements were made by Barrer's high vacuum technique; others were made by measuring volumetric change as a function of time. Sorption isotherms were obtained by using a quartz helix microbalance. Temperature dependent permeability constants have been obtained for permeation of oxygen, nitrogen, and carbon dioxide through styrene, acrylonitrile, and vinylpyridine grafted to low‐density polyethylene. Permeability constants at 25°C. have also been determined as a function of water vapor partial pressure for the above systems. Some values for permeation of carbon dioxide through styrene grafted to high density or linear polyethylene are also given. Organic vapors studied were methyl bromide and isobutene, permeability constants at 0°C. being determined for styrene and acrylonitrile–polyethylene graft copolymers as a function of organic vapor pressure. The data show clearly that permeation through acrylonitrile and vinylpyridine–polyethylene grafts is primarily a diffusion process, while in permeation through polyethylene–styrene grafts, there is also a crystallite solution effect. Percentage grafts varied from 0 to 100 parts monomer per 100 parts by weight polyethylene.