PROCESS FOR PREPARING ACID DIFFUSION-DIALYSIS MEMBRANE

摘要

1340970 Production of diffusion dialysis membranes ASAHI GLASS CO Ltd 29 Dec 1971 [29 Dec 1970] 60568/71 Heading C3P [Also in Divisions C2 and B1] An acid diffusion dialysis membrane is prepared by polymerizing a monomer mixture including a monomer I, selected from vinyl benzenes and vinyl pyridines, and a monomer II being a non-conjugated divinyl compound, in the presence of at least one thermoplastic or elastomeric polymer III being swellable in the monomer mixture, to form a film having a thickness of 4-100 microns, and then introducing anion exchange groups into the resulting film. The weight ratio of monomer II to monomer I is preferably 1-25 to 100. The ratio of the polymer III to the monomer mixture is preferably 100-600 to 100. Polymer III may be in the form of a film, which is dipped in the monomer mixture such that it is swelled, and the monomer mixture absorbed therein is then polymerized. Alternatively polymer III may be in the form of a powder or granules, which is admixed with the monomers, formed into a film and polymerized. Polymerization may be brought about by heat/initiator, or by photopolymerization or high energy radiation. Monomer I may be styrene, in which case the ion exchange groups are introduced by halo methylation and then amination. It may also be an ar-halo styrene, in which case amination is only necessary. If monomer I is a vinyl pyridine, quaternization is used. Examples of the divinyl compound II are divinyl benzene, and ethylene glycol diacrylate or -methacrylate. Examples of polymer III are homo- and copolymers of vinyl chloride, vinylidene chloride, ethylene and propylene, and styrene/butadiene rubber, butyl rubber, chlorinated polyethylene rubber, acrylonitrile/butadiene rubber, and chlorosulphonated polyethylene rubber. Polyphenylene oxide is also mentioned. Polymerization may also be in solution, in which case the film is cast.