Preparation and characterization of SMA/S-POSS hybrid membranes for direct methanol fuel cell applications

Abstract

A novel sulfonated polyhedral oligomeric silsesquioxane(S-POSS) monomer was synthesized successfully in this article. S-POSS acted as a donor of sulfonic acid group and reacted with poly (styrene-co-maleic anhydride) (SMA). FT-IR spectroscopy confirmed the modification through introduction of peaks characteristic of ester linkages and carboxylic groups. The SMA/S-POSS hybrid membranes were fabricated from different S-POSS contents. The proton conductivity and methanol permeability of the hybrid membranes were studied with changing S-POSS content from 5wt. % to 30wt. %. It was found that the proton conductivity and the methanol permeability were dependent on the S-POSS content. Both of proton conductivity and methanol permeability properties improve with increasing S-POSS content. The proton conductivities of the hybrid membranes are in the range of 10(-3) - 10(-2) S center dot cm(-1), and the range of methanol permeabilities was between 10(-8) and 10(-7) cm(2)center dot s(-1). The membranes show good thermal properties characterized by thermogravimetric analysis (TGA).