Abstract

• Membrane is one of the key performances for Direct Methanol Fuel cell(DMFC). A new polymer electrolyte membrane based on polystyrene sulphonated has been developed. In this research, the polystyrene sulphonated membrane was a casted product that obtained by the sulphonation of polystyrene with concentrated sulphuric acid. The polystyrene sulphonated membranes have been characterized by properties of ion exchange capacity, and water uptake as a function of molar ratio of polystyrene to concentrated H2SO4, FTIR, SEM and EDXRF. The S content of the prepared membrane was determined using titration method. Fourier Transform Infrared (FTIR) was performed to verify the sulphonation reaction on the polystyrene polymer. Morphology of the prepared membranes were characterized by Scanning Electron Microscopy (SEM). The chemical constituents of polystyrene sulphonated membranes were detected by using Energy Dispersive X-ray Fluorescence (EDXRF). At the optimal temperature of 40 ± 2˚C for the time of 2 h, the optimal composition ratio of polystyrene to concentrated H2SO4 (w/v) was found to achieve as 1:2. The polystyrene sulphonated membrane has an ion exchange capacity of 0.79 meq/g and S content of 2.53 %. Therefore, the prepared polystyrene sulphonated membranes were suitable for the low temperature fuel cell, especially Direct Methanol Fuel Cell (DMFC) due to the range of ion exchange capacity 0.45-0.79 meq/g.