Characterization of PVA and phenol salt modified tin dioxide cationic membranes

Abstract

In polymeric electrolytes for transporting protons, polyvinyl alcohol (PVA) is not toxic to the environment, has low cost, forms flexible and resistant films. Functionalized by the insertion of acid groups and inorganic oxides tin modified with phenol salt (Tiron), they have good conduction capacity. In this work, PVA membranes modified with sulfonic acids and phenol salt were synthesized and characterized by TGA, DMA and FTIR spectra that confirmed the crosslinking reaction via esterification. The IEC values ranged from 0.11 to 3.9 mEq.g−1. The membranes exhibited thermal resistance and chemical stability when exposed to Fenton's reagent, superior to PVA. With the impedance analysis, an increase in the conductivity was observed with the increase of the oxide modified concentration, confirmed by Nyquist diagrams and equivalent circuits, being the best results obtained by the membranes PASF306 (σ = 2.1 mS cm−1) and PASS305 (σ = 1.96 mS cm−1). The membranes were tested in a prototype fuel cell with pure hydrogen and showed application potential.