PREPARATION OF ION EXCHANGE MEMBRANES FROM GRAFT COPOLYMERS OBTAINED BY VAPOUR PHASE RADIATION GRAFTING

Journal Article · Tue Jan 01 04:00:00 EST 1963 · Proc. Japan Conf. Radioisotopes

OSTI ID:4697514

Shinohara, K; Yanagita, M; Kawabe, H; Takamatsu, T; Tanaka, M

The preparation of ion exchange membranes from graft copolymers obtained by radiation grafting of ionogenic monomers to polyethylene powder is reported. Monomers used were methyl acrylate (MA), ethyl acrylate (EA), 4-vinyl pyridine (VP), 2-methyl-5-vinyl pyridine (MVP), styrene (St), and vinyl acetate (VAc). Polyethylene powder of molecular weight 23000 and particle size 100-mesh was irradated in a monomer vapor by Co/sup 60/ gamma rays of about 800 C or by electrons at 1.6 Mev, washed with a suitable solvent, and dried in vacuo. The dose rate of the gamma rays was 1.9 x 10/sup 3/ r/hr and that of the electron beanns was 6 x 10/sup 4/ rads/sec. Degree of the graft was calculated from an increase in the weight of the polymer due to grafting. It was also obtained from O or Ni content of ths graft copolymers determined by elementary analysis. Both values showed a good agreement with each other. The degree of graft obtained at a given dose of radiation for different kinds of monomers increased in the onder of VAc, MVP, VP, EA, St, and Ma. The efficiency for electron radiation was lower than that for gamma rays. Carboxylic-type membranes (CW-1) were prepared by saponification of MA or EA graft copolymer films with alcoholic potash of 1 N-KOH concentration. Sulfonic acid-type membranes were prepared by sulfonation of St graft copolymer films with concentrated sulfuric acid containing 1% Ag/sub 2/SO/ sub 4/. Pyridinium-type membranes (AS-1) were prepared by quatennarization of VP or MVP graft copolymer films with a mixture of methyl iodide and a suitable organic solvent such as nitromethane and acetone prepared in 1: 1 volume ratio. In all cases, conversion of functional groups of graft copolymers to ion exchange groups could be carried out easily and almost completely, except when the value of the degree of graft was fairly small. In addition to the above membranes, those containing strong acid groups (CS-1) were prepared from VAc graft copolymer films by de-acetylation and succeeding treatment with 30% fuming sulfonic acid. St sulfonic acid type membranes were found to be inferior to CW-1 and As1 in their properties, especially in their durability. CS-1 had high ion selectivity and durability. (P.C.H.)

• Research Organization: Inst. of Physical and Chemical Research
• NSA Number: NSA-17-030191
• OSTI ID: 4697514
• Journal Information: Proc. Japan Conf. Radioisotopes, Journal Name: Proc. Japan Conf. Radioisotopes Vol. Vol: 5th, No. 4
• Country of Publication: Country unknown/Code not available
• Language: Japanese

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