Radiation grafting of α,β,β‐trifluorostyrene onto poly(ethylene‐tetrafluoroethylene) film by preirradiation method. II. Properties of cation‐exchange membrane obtained by sulfonation and hydrolysis of the grafted film

Abstract A Study was made on certain properties of the cation‐exchange membranes obtained by the preirradiation grafting of α,β,β‐trifluorostyrene (TFS) noto poly(ethylene‐tetrafluoroethylene) (ETFE), followed by sulfonation and hydrolysis of the grafted film. Swelling, water uptake, electric conductivity, and transport number of the membranes were measured as a function of ino‐exchange capacity. Thermal and chemical stability were also investigated. These properties were found to be mainly dependent on ion‐exchange capacity. The stable membrane properties were established due to a homogeneous ion‐exchange group distribution in the membrane, as confirmed by x‐ray imcroscopy analysis of the membrane cross sections. In addition, the membranes showed good electrochemical, thermal, and chemical properties, and were found to be scceptable for practical use as cation‐exchange membranes.