Novel Proton Exchange Membranes Based on Sulfonated Poly(acrylonitrile-co-glycidyl methacrylate)/Poly(vinyl chloride) Composite

Abstract

In this study, novel proton exchange membranes (PEMs) based on a composite of sulfonated polyacrylonitrile (SPAN), sulfonated polyglycidyl methacrylate (SPGMA), or sulfonated poly(acrylonitrile-co-glycidyl methacrylate) (SP(AN-co-GMA))/polyvinyl chloride (PVC) were developed to be used for direct methanol fuel cells (DMFCs). After polymerization and sulfonation of the prepared polymers, the polyelectrolyte membranes were prepared by the casting and solvent evaporation technique for sulfonated homo- or co-polymers with polyvinyl chloride (PVC) composites. The resulting membranes were characterized by Fourier infrared and Raman spectral analyses, X-ray diffractometry, and scanning electron microscopy. The findings of this study reveal that both the thermal stability and ion exchange capacity of the composite membranes based on sulfonated copolymers were higher than that of their corresponding composites based on sulfonated homopolymers. In this context, the weight loss percentage of the prepared composite polyelectrolyte membranes did not exceed 12% of their initial weights. The IEC of all the composite membranes ranged from 0.18 to 0.48 meq/g. Thus, the IEC value increased with the increasing proportion of the glycidyl methacrylate comonomer. Moreover, the prepared PEMs based on SP(AN-co-GMA)/PVC composites showed lower methanol permeability (8.7 × 10−7 cm2/s) than that of the Nafion membranes (3.39 × 10−6 cm2/s). Therefore, these prepared PEMs are a good candidate for DMFCs applications.