Radiation–Grafted Alkaline Anion–Exchange Membranes Prepared with Reduced Monomer Quantities

Alkaline anion–exchange membranes (AAEM) for alkaline polymer electrolyte fuel cells (APEFC) were successfully prepared using electron beam irradiated poly(ethylene–co– tetrafluoroethylene) precursor films grafted with vinylbenzyl chloride (VBC) monomer. The resulting chloromethyl groups were subsequently reacted with trimethylamine to form quaternary ammonium anion–exchange functional head–groups. The concentration of toxic and expensive VBC, that is required to achieve an optimal level of grafting, was reduced from 100%v/v (undiluted) to 20%v/v by dilution with propan–2–ol and the inclusion of a surfactant. Fuel cell tests using hydrogen and oxygen gave the same peak power densities (164 ± 3 mW cm–2) for the AAEMs prepared with both 100%v/v VBC and 20%v/v VBC. This highlights the (desirable) lack of any detrimental effect on performance of the resulting APEFC with the reduction in grafting monomer concentration used for the synthesis of the component AAEM.