Conductivity and Thermal Behaviour of Sulfonated ABS Membranes for Fuel Cell Applications

摘要

In the present work, proton conductive membranes based on poly(acrylonitrile-co-butadiene-co-styrene) (ABS) were obtained by sulfonation. The sulfonic acid ABS (ABS-SO_3H) membranes exhibited thermal stability near 370°C, similarly to the ABS original polymer. DSC curves of the sulfonic acid membranes showed two glass transition temperatures, associated with thermal processes taking place at the polymer main chain and at the hydrophilic domains. These hydrated regions are formed by water molecules and dissociated sulfonic acid groups [-SO_3~-(H_2O)_nH~+], as pointed out in other works. Electrochemical impedance spectroscopy evidenced the conductive-capacitive behaviour of ABS-SO_3H membranes, which exhibited an Ahrrenius-like conductivity dependence with temperature, from 7.6×10~(-6) Ω~(-1)cm~(-1) at 20°C and 1.4×10~(-5) Ω~(-1)cm~(-1) at 80°C (ABS-SO_3H 2:1).