Document Type: Research Paper
Department of Chemical Engineering, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132, Indonesia
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).