preparation and characterization of heterogeneous pvc-silica proton exchange membrane

heterogeneous proton exchange membranes (pem) are synthesized using the dry phase inversion technique. the casting solutions are prepared by dispersing a finely ground cation exchange resin particle in n,n-dimethylacetamide (dmac) solution of polyvinyl-chloride (pvc). results show that ion exchange capacity is increased with the addition of 1 %-wt nanosilica (from 0.14 to 0.27 meq/g) while it is decreased with a higher concentration of silica. the incorporation of 0.5%-wt nanosilica improves water uptake (from 79.2% to 94.9%) and proton conductivity (from 0.02 to 0.09 ms/cm) of pem. however, at further silica loading those properties are decreased. the membrane with 1%-wt nanosilica and 50%-wt resin showed very good stability in the oxidative environment. the post-treatment via membrane sulfonation at the optimum condition (0.1 m of sulfuric acid and 1 h reaction time) reduces the water uptake (from 94.8% to 92.3%) but improves the iec (from 0.27 meq/g to 0.49 meg/g) and proton conductivity (from 0.02 ms/cm to 3.07 ms/cm). meanwhile, the post-treatment via salt solution immersion at the optimum condition (0.1 m, 24 h and 30 oc) produces less water uptake (from 94.8% to 93.1%) but improves the iec (from 0.27 meq/g to 0.55 meg/g) and drastically increases the proton conductivity (from 0.02 ms/cm to 2.79 ms/cm).