Preparation and properties of phosphorylated and crosslinked poly(vinyl alcohol)/bisphenol A-epoxy resin membranes for fuel cell applications

摘要

To overcome the strong dependence of the conductivity on the relative humidity and the lower thermal stability at high temperature of perfluorosulfonate polymers and the leaching-out problem of phosphoric acid doped membranes, a series of phosphorylated and crosslinked poly(vinyl alcohol) (PVA)/bisphenol A-epoxy resin [diglycidyl ether of bisphenol A (DGEBA)] membranes were prepared. The membrane properties were characterized by Fourier transform infrared spectra, solubility, thermogravimetric analysis, water uptake, swelling ratio, ion-exchange capacity (IEC), small-angle X-ray scattering, and proton conductivity measurements. The results show that the crosslinked PVA/DGEBA membrane had a higher thermal stability (T_d ≤yen; 250°C) than the pure PVA membrane (T_d ≤yen; 220°C) and that the phosphorylated and crosslinked PVA/DGEBA membranes (IEC = 5.54 mmol/g) with a low volume swelling ratio (7.21%) could achieve a maximum proton conductivity of 2.51 × 10~(-3) S/cm at a temperature as high as 150°C in anhydrous conditions