Influence of silicon oxide (SiO2) and sulfosuccinic acid (SSA) loading on properties of poly(vinyl alcohol) (PVA) derived composite membranes

Abstract

New anhydrous proton conducting membranes based on poly(vinyl acohol) (PVA), tetraethyl orthosilicate (TEOS) and sulfosuccinic acid (SSA) were prepared in a single step using the solution casting method, with the aim to improve the mechanical properties of PVA membranes. SSA has been used as a sulfonating agent for crosslinking the membrane structure and also as a source of protons. TEOS has been used as crosslinking agent to increase the thermal and mechanical properties of the membranes and membranes stability in aqueous environment. In order to verify that all the substances were immobilized into the matrix, the membranes were analyzed by means of Fourier transform infrared spectroscopy (FTIR).The thermal, mechanical and rheological properties of the membranes were investigated by means of thermogravimetry (TGA), dynamic mechanical analysis (DMA) and Ares G2 rheometer. Water uptake (Wu) of composite membranes was determined. The properties were investigated for various PVA solutions and for each dried membrane. The analysis of mixed PVA solutions exhibited unique behaviour of viscosity with increasing the crosslink density. TGA and DMA measurements showed increased thermal and mechanical resistance of membranes depending on the extent of their crosslinking. Due to incorporation TEOS, the resistance of PVA membranes to the aquatic environment has increased. These properties can increase the resistance of the membranes during the processes occurring in the fuel cells.