Electrodialytic Transport Properties of Anion-Exchange Membranes Prepared from Poly(vinyl alcohol) and Poly(vinyl alcohol-co-methacryloyl aminopropyl trimethyl ammonium chloride)

Random-type anion-exchange membranes (AEMs) have been prepared by blending poly(vinyl alcohol) (PVA) and the random copolymer-type polycation, poly(vinyl alcohol-co-methacryloyl aminopropyl trimethyl ammonium chloride) at various molar percentages of anion-exchange groups to vinyl alcohol groups, C(pc), and by cross-linking the PVA chains with glutaraldehyde (GA) solution at various GA concentrations, C(GA). The characteristics of the random-type AEMs were compared with blend-type AEMs prepared in our previous study. At equal molar percentages of the anion exchange groups, the water content of the random-type AEMs was lower than that of the blend-type AEMs. The effective charge density of the random-type AEMs increased with increasing C(pc) and reached a maximum value. Further, the maximum value of the effective charge density increased with increasing C(GA). The maximum value of the effective charge density, 0.42 mol/dm(3), was obtained for the random-type AEM with C(pc) = 4.2 mol % and C(GA) = 0.15 vol %. A comparison of the random-type and blend-type AEMs with almost the same C(pc) showed that the random-type AEMs had lower membrane resistance than the blend-type ones. The membrane resistance and dynamic transport number of the random-type AEM with C(pc) = 6.0 mol % and C(GA) = 0.15 vol % were 4.8 Ω cm(2) and 0.83, respectively.