PROTON-EXCHANGE MEMBRANES PREPARED BY SIMULTANEOUS RADIATION GRAFTINGOF STYRENE ONTO TEFLON-FEP FILMS - SYNTHESIS AND CHARACTERIZATION

Proton exchange membranes were prepared by simultaneous radiation graf ting of styrene onto Teflon-FEP films and subsequent sulfonation. Degr ees of grafting from 13 to 52% were obtained. FTIR-ATR in combination with FTIR measurements show a homogeneous distribution of polystyrene across the grafted film. Water uptake after swelling in boiling water and specific conductivity of the sulfonated membranes were determined. The strong decrease in specific resistivity with increasing degree of grafting is due to an increasing proton mobility, reflected by an inc reasing hydration of the sulfonic acid groups. For degrees of grafting higher than 30% specific resistivity values as low as 2 OMEGA-cm (20- degrees-C) are measured,