抄録
Anion–exchange membranes with permselectivity for mono–valent ions were prepared by three step processes: (1)graft polymerization of chloromethylstyrene (CMS) onto an ultrahigh–molecular–weight polyethylene (UHMWPE) film that had previously been irradiated with an electron beam, (2) reaction between N, N, N, N–tetramethyl–1, 6–hexanediamine (TMHDA) and the CMS graft chains via exclusive crosslinking near both sides of the CMS–grafted UHMWPE film, and (3) introduction of trimethylammonium groups into the remaining CMS graft chains by reaction with trimethylamine. The resulting TMHDA–treated anion–exchange membrane and currently used cationexchange membrane, Selemion® CSO, were both installed in an elecrodialyzer to evaluate their chloride ion selectivity, as well as the resulting brine concentration in the concentrating chamber. Crosslinking of the CMS graft chain with TMHDA and the subsequent introduction of a trimethylammonium group onto the CMS–grafted films with a degree of grafting of >50% clearly exhibited the membrane resistance and a chloride-ion permeability that is comparable with that of the currently used anion–exchange membrane, Selemion® ASA. In addition, the prepared membranes with the same membrane resistance as Selemion® ASA produced brine with 5 ～ 10% higher concentrations than ASA membrane.
