Sulfonated Polystyrene Copolymer: Synthesis, Characterization and Its Application of Membrane for Direct Methanol Fuel Cell (DMFC)

Abstract

A novel Sulfonated Polystyrene (PSS) has been synthesized by sulfonation polystyrene waste for a comparative study of proton exchange membranes (PEM) that is intended for fuel cell applications. The degree of sulfonation (DS) of the sulfonated PS was determined using titration method. We systematically investigated the water uptake, proton conductivity, and methanol permeability of the cross-linked membranes. The mass averaged molecular weights Mw of PSS was estimated from intrinsic viscosities measured in sulfuric acid solutions. A related homopolymer was characterized by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The structures of PSS were elucidated, and the effect of sulfonation level on the PSS FT-IR spectrum was studied. PSS membrane surface morphology was investigated by SEM and AFM. The highest of proton conductivity of the membrane in the temperature range of 25–750C was found to be 3.8 μS/cm