Silane crosslinked structure-introduced fuel-cell polymer electrolyte membrane and fuel-cell electrode assembly having the same

Abstract

An object is to provide an electrolyte membrane that maintains excellent cell characteristics for a long time under high temperature and low water retention, as this is the most important point in fuel cells. A process for producing a polymer electrolyte membrane for fuel cells is provided, which process comprises in sequence: forming graft molecular chains by graft-polymerization of a vinyl silane coupling agent on a polymer film substrate that has phenyl groups capable of holding sulfonic acid groups; introducing sulfonic acid groups into phenyl groups contained in the graft molecular chains; and hydrolyzing and condensing alkoxy groups contained in the graft molecular chains so that a silane crosslinked structure is introduced between the graft molecular chains. A polymer electrolyte membrane produced by the process is also provided.