| 摘要 |
An ion-selective membrane is made by plasticizing a polyvinyl acetal and milling the plasticized acetal in the absence of a solvent with a finely divided ion-exchange resin to an homogeneous dispersion which is formed into a sheet. Specified plasticizers are tri-tolyl phosphate, polychloroprene, polypropylene adipate and a 1,3-butadiene-acrylonitrile polymer. Specified ion-exchange resins are chlorinated, aminated or sulphonated cross-linked polystyrene resins, sulphonated phenol-formaldehyde resins, the reaction products of acrylic or methacrylic acid with a cross-linking agent, a phenol-formaldehyde-chloracetic acid condensate, a phenolformaldehyde-polyethylene polyamine condensate and an acetone-formaldehyde-guanidine salt condensate. In the example, polyvinyl formal is plasticized with a butadiene-acrylonitrile co-polymer, mixed with a sulphonated cross-linked polystyrene cation-exchange resin and formed into a sheet.
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