Studies on the electrochemical properties of copolymers of maleic acid, IV : comparison of chelate formation constant

Abstract

The apparent chelate formation constants of alkaline earth metal ions, Ba and Ca, with maleic acid-vinyl acetate and maleic acid-styrene copolymers were evaluated according to Morawetz's method and the comparison between two copolymers was done. At low charge density per carboxyl pair, the formation constant for the styrene copolymer was smaller than that for the vinyl acetate copolymer. At high charge density per carboxyl pair, the reverse relation was obtained. The results were explained by taking the influence of the neighboring ionized groups beyond the comonomer and that of the field effect of polyion into consideration.