PARTIALLY SULFONATED POLY(ARYLENE ETHER SULFONE) - A VERSATILE PROTON CONDUCTING MEMBRANE MATERIAL FOR MODERN ENERGY-CONVERSION TECHNOLOGIES

Sulfonated poly(arylene ether sulfones) with various sulfonation levels have been prepared and evaluated as solid polymer electrolytes in electrolysers and fuel cells. Solution and slurry sulfonation of poly(arylene ether sulfones) such as Udel(R) P-1700 (PSU) and Victrex(R) PES 5200P (PES) yield polyelectrolytes which have been characterized using FTIR and H-1-NMR spectroscopy, titration, thermal analysis, and electrochemical characterization such as resistivity, selectivity of ion permeation, current/voltage plot and life time test in an electrolysis cell. In contrast to the sulfonated PSU, the PES sulfonated in a slurry process was water insoluble, even at high sulfonation levels of 90 mol%, and gave significantly improved electrochemical properties similar to those of fluorine-containing polyelectrolytes used in commercial membrane systems. A versatile in-situ crosslinking technique has been developed to crosslink the sulfonated poly(arylene ether sulfone) electrolytes during membrane processing in order to substantially reduce water swelling without impairing other membrane properties such as proton conductivity.