Radiation modification of sulfonated hydrocarbon membrane for proton exchange membrane fuel cell (PEMFC)

Abstract

Polymer modifications such as crosslinking and grafting by radiation have been widely used in the field of bio polymer, hydrogel, heat-resisting electric wire, vulcanization, polymer recycling. Recently, the research field has been enlarged to polymer electrolyte for proton exchange membrane fuel cell (PEMFC). In general irradiation process, sulfonic acid groups are introduced to the crosslinked or grafted polymers after irradiation step (pre-irradiation and post-sulfonation) to prevent unexpected membrane damage such as decomposition of sulfonic acid groups. As a result, there are just a few papers for post-irradiation of sulfonated polymer. In this study, sulfonated polyarylene ether sulfone (SPAES) membranes were successfully grafted with acrylic acid by post-irradiation method. Diverging from the normal concern, radiation-grafted SPAES seemed not to be decomposed seriously. Furthermore, they showed higher water uptakes and proton conductivities due to carboxylic acid groups of acrylic acids. However, excessive grafting rate made mechanical stability of radiation-grafted SPAES reduced.