| 摘要 |
Weak acid cation-exchange resins are made by treating a high molecular weight organic nitrile-containing polymer with a hydrolytic agent to convert at least some of the nitrile groups into carboxylic acid groups. Polymers specified are homopolymers of acrylonitrile, methacrylonitrile, ethacrylonitrile, fumaryl dinitrile and vinylidene cyanide, and copolymers of such monomers, e.g. copolymers of acrylonitrile with vinyl chloride, acrylic acid or methacrylic acid and a copolymer of vinylidene cyanide and vinyl acetate cross-linked with diphenylmethane diisocyanate. As a hydrolytic agent there is specified aqueous sulphuric acid of 50-70% strength. The final cation-exchange product is in fibrous form, the formation of fibres taking place either before or after the hydrolysis reaction. The products are able to combine with free bases such as ammonia, pyridine and streptomycin. |
