Synthsis and Property of Dialysis Membranes with Anti-radiation Property

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Poly(vinyl chloride) was reacted with sodium N-methyl-Ncarboxymethy dithiocarbamate to produce a modified PVC containing N-methyl-N-carboxymethyl dithiocarbamate(SDC) group. The modified PVC showed the excellent performance for a dialysis membrane with anti-radiation property against gamma-irradiation.A chemically modified polysulfone(SDC-PSF) containing SDC group has also prepared by the reaction of chloromethylated polysulfone with sodium N-methyl-N-carboxymethyl-dithiocarbamate in dimethylformamide. Asymetric SDC-PSF membranes prepared were brou-ght to dyalysis test and reverse osmosis tests at p=10kg/cm^2and 25゜C with 1000ppm NaCl solution and feed solutions containing some low molecular organic solutes. Tri-ethylammonium polysulfone, TEA-PSF membranes were also preprred and tested. The SDC-PSF membranes showed higher water flux than the TEA-PSF membranes. This is attribu-ted to the bulky hydrophilic group of the SDC. The SDC-PSF membranes were modified by copper chelation or by irradiation with ultraviolet light. These modified SDC-PSF membranes showed higher rejection for isopropanol, sucrose and beta-cyclodextrin, while the water flux decreased only 10 % compared with that of the original SDC-PSF memb-ranes. An equation for salt rejection in reverse osmosis operation was derived from the assumption of the Donnan equilibrium. Experimental results of salt rejection were compared with theoretical values calculated with effective fixed charge densities obtained from membrane potential experiments and with thermodynamic partition coeffi-cients from sorption-desorption experiments that were measured in homogeneous SDC-PSF membranes. The SDC-PSF membranes showed the excellent antiradiation property forthe performance as the dialysis membrane until 40 mrad of gamma-irradiation from Co-60.The copolymer of acrylonitrile-metharylchloride has also been modified by the iden-tical technique with the modification of the modified PVC and SDC-PSF.