VAPOR AND GAS-PERMEABILITY OF POLYURETHANE MEMBRANES .2. EFFECT OF FUNCTIONAL-GROUP

Functional groups, i.e. tertiary amine and carboxyl groups, were introduced into polyurethane membranes in order to investigate the effects of these groups on the vapor and gas permeability of the membranes. It was observed that, when the contents of the functional groups increased, the crystallinity, density and glass transition temperature of the membranes increased, whereas the vapor and gas permeability of the membranes decreased. The oxygen/nitrogen separation coefficient increased with increasing functional group content in the membrane, and was strongly dependent on the character of the functional group.