Sulfonated gamma-irradiated blend poly(styrene/ethylene-vinyl acetate) membrane and their electrical properties

Abstract

A compatibilized blend membrane of polystyrene (PS)/polyethylene-vinyl acetate (PEVA) (50: 50) wt % was produced by compression molded at 180°C after irradiated by gamma ray at 50-kGy dose. The influence of gamma radiation on the properties of the blend (PS/PEVA) membrane was investigated. The irradiated samples showed an increase in the degree of crystallinity due to the presence of additional chemical bonds as observed by X-ray diffraction. As a result of irradiation, the miscibility of the two polymer matrix is enhanced by interfacial adhesion between the components in the blend polymer without any voids as observed by scanning electron microscopy. Furthermore, electrical conductivity in the blend (PS/PEVA) membrane was enhanced by introducing SO3H groups. Sulfonation process converts the blend from noncontact (5 × 10−8 S cm−1) to semi-contact (3.8 × 10−3 S cm−1) by AC current at wet condition, and this can find applications in the fuel cells.