Abstract: A crosslinked nano-inorganic particle/polymer electrolyte membrane composed of a polymer film substrate, graft molecular chains bound to the backbone skeleton of the polymer film substrate and comprising a vinyl monomer graft-polymerized, sulfonic groups bound to the graft molecular chains, and an inorganic material as nano-scale particles uniformly dispersed within a crosslinked structure ascribed to the backbone skeleton of the polymer film substrate and the graft molecular chains, wherein the backbone skeleton of the polymer film substrate, the graft molecular chains, and the nano-inorganic particles mutually construct a crosslinked structure.

Abstract: A polymer electrolyte membrane produced by a process in which a monofunctional vinyl monomer into which sulfonic acid groups can be introduced and a vinyl monomer having a halogen at a terminal are co-grafted into a polymer base film that has been exposed to an ionizing radiation, and the base film is exposed again to an ionizing radiation and/or heat treated so that the terminal halogen is eliminated to introduce a crosslinking structure in which the graft molecular chains are bound together.

Abstract: Polymer ion-exchange membranes having outstanding electrical conductivity, water retention and oxidation resistance are produced by the steps of uniformly mixing an organic high-molecular weight resin with functional inorganics having the abilities to promote graft polymerization of polymerizable monomers, adsorb water and conduct protons, irradiating the resulting functional inorganics/polymer membrane to initiate graft polymerization or graft copolymerization of polymerizable monomers having functional groups, and then introducing sulfonic acid groups into the graft chains.

Abstract: The objective of the invention is to solve the problems of conventional polymer electrolyte membranes, including small ion-exchange capacity and low oxidation and methanol resistance. A polymer film substrate is irradiated with ?-rays, electron beams or other radiations to perform multi-graft polymerization with functional monomers and then the polymer film substrate containing the grafted molecular chains or the graft molecular chains into which sulfonic acid groups have been introduced is crosslinked by irradiation to produce a polymer electrolyte membrane that has outstanding oxidation resistance, dimensional stability, electrical conductivity and methanol resistance and which can be controlled in ion-exchange capacity over a wide range.

Abstract: The improved electrolyte membrane which is produced by grafting a styrenic monomer and bis(vinylphenyl)ethane as monomers to a polymer substrate and then introducing sulfonic acid groups into the graft side chains formed has improved oxidation resistance and good adhesion to electrodes. The polymer substrate is preferably made of a fluorocarbon polymer or an olefinic polymer. The styrenic monomer is preferably one or more species selected from the group consisting of styrene, ?-methylstyrene, vinyltoluene, and trifluorostyrene.

Abstract: A polymer film substrate is irradiated with ions to make a large number of nano-sized through-holes and the substrate is further irradiated with an ionizing radiation so that a functional monomer is grafted or co-grafted onto a surface of the film and within the holes; in addition, the sulfonic acid group is introduced into the graft chains, thereby producing a polymer ion-exchange membrane that has high oxidation resistance, dimensional stability, electrical conductivity and methanol resistance, as well as an ion-exchange capacity controlled over a wide range.