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AssigneesJapan Atomic Energy Agency, Nitto Denko Corporation
InventorsMasaru Yoshida, Tetsuya Yamaki, Masaharu Asano, Yousuke Morita, Soji Nishiyama, Toshimitsu Tachibana, Yozo Nagai
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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.
A process for producing a hybrid ion-exchange membrane comprising functional inorganics and a graft polymer, which comprises the steps of adding at least one inorganic fine powder selected from the group consisting of fine particulate amorphous silica (SiO2), H+ form mordenite ((Ca,Na2,K2)Al2Si10O24.7H2O), alumina (Al2O3), and zirconium oxide (ZrO2) to an ethylene-tetrafluoroethylene copolymer as a thermoplastic polymer in an amount ranging from 1 wt % to 20 wt % of the polymer, mixing the ingredients uniformly, shaping the mixture to form a functional inorganics/polymer membrane, exposing the functional inorganics/polymer membrane to an ionizing radiation for a total dose ranging from 10 kGy to 1 MGy, then bringing the membrane into contact with the oxygen-free polymerizable monomer styrene so that the styrene is grafted to the functional inorganics/polymer membrane to prepare a functional inorganics/graft polymer membrane, and reacting the functional inorganics/graft polymer membrane with chlorosulfonic acid to introduce sulfonic acid groups into the phenyl groups in the graft chains.
A process for producing a hybrid ion-exchange membrane comprising functional inorganics and a graft polymer, which comprises the steps of adding at least one inorganic fine powder selected from the group consisting of zirconium phosphate (Zr(HPO4)2.nH2O), phosphotungstic acid hydrate (H3PW12O40.nH2O), silicotungstic acid hydrate (H4SiW12O40.nH2O), and molybdophosphoric acid hydrate (MoO3H3PO4.nH2O) to an ethylene-tetrafluoroethylene copolymer as a thermoplastic polymer in an amount ranging from 1 wt % to 20 wt % of the polymer, mixing the ingredients uniformly, shaping the mixture to form a functional inorganics/polymer membrane, exposing the functional inorganics/polymer membrane to an ionizing radiation for a total dose ranging from 10 kGy to 1 MGy, then bringing the membrane into contact with the oxygen-free polymerizable monomer styrene so that the styrene is grafted to the functional inorganics/polymer membrane to prepare a functional inorganics/graft polymer membrane, and reacting the functional inorganics/graft polymer membrane with chlorosulfonic acid to introduce sulfonic acid groups into the phenyl groups in the graft chains.
A process for producing a hybrid ion-exchange membrane comprising functional inorganics and a graft polymer, which comprises the steps of adding at least one inorganic fine powder selected from the group consisting of amorphous silica having phosphotungstic acid hydrate, zirconium phosphate or silicotungstic acid hydrate adsorbed thereon, as well as mordenite and alumina having phosphotungstic acid hydrate, zirconium phosphate or silicotungstic acid hydrate adsorbed thereon to an ethylene-tetrafluoroethylene copolymer as a thermoplastic polymer in an amount ranging from 1 wt % to 20 wt % of the polymer, mixing the ingredients uniformly, shaping the mixture to form a functional inorganics/polymer membrane, exposing the functional inorganics/polymer membrane to an ionizing radiation for a total dose ranging from 10 kGy to 1 MGy, then bringing the membrane into contact with the oxygen-free polymerizable monomer styrene so that the styrene is grafted to the functional inorganics/polymer membrane to prepare a functional inorganics/graft polymer membrane, and reacting the functional inorganics/graft polymer membrane with chlorosulfonic acid to introduce sulfonic acid groups into the phenyl groups in the graft chains.
Dependencies are inferred from the claim text.