| 摘要 |
Ion-exchange membranes consist of a solid organic film made of a substance comprising a first polymeric material which is substantially chemically inert, i.e. substantially unreactive in respect of ion-exchange activity and substantially water-insoluble, in intimate molecular combination with a second polymeric material containing ion-exchange groups which is derived from an ethylenically unsaturated monomer, the intimate molecular combination being such that the components are a single entity inseparable by leaching. Suitable inert polymers are rubber, polyamides, urea and phenolic resins and polymers of ethylene, propylene, vinyl and vinylidene halides, acrylonitrile, alkyl acrylates and methacrylates, vinyl ethers and butadiene, e.g. a butadiene-acrylonitrile rubbery copolymer. Suitable ethylenic monomers are styrene, methyl styrene, alpha-chloro- and -bromo-styrenes, halogenated styrene, chloromethyl and bromoethyl styrenes, esters of styrene sulphonic acid, vinyl piperidine, pyridine, lutidine, carbazole, sulphones, naphthalene and aniline, acrylic and methacrylic acids, allylamine and dimethylaminoethyl and diethylaminoethyl methacrylates; these monomers may be used in admixture with one another or with cross-linking monomers such as divinyl benzene, ethylene dimethacrylate, diallyl carbonate and phthalate and triallyl cyanurate. The preparation of the polymeric materials and the subsequent introduction therein of ion-exchange groups, if necessary, is described in Specification 872,218. Specifications 872,219 and 872,220 also are referred to. |
