In this paper, proton conducting composite membranes of Nafion®-mordenite for direct methanol fuel cell (DMFC) were prepared using solution casting method. Mordenite, used as inorganic filler, was incorporated into Nafion polymer in order to improve membrane properties for DMFC application. Effect of solution casting temperature on resulting composite membranes was focused. The temperature of the membrane preparation was varied from 80 to 120°C. Properties and morphology of the resulting membranes including solubility, water uptake, ion – exchange capacity were investigated and reported. It was found that composite membrane prepared at 100°C gave the most alcohol resistance and mechanical stability membrane with 0.59% soluble. Furthermore, it gave highest ion – exchange capacity, 0.10 meq⋅g-1, which is 33% and 98% higher than the membranes prepared at 80°C and 120°C respectively.
