Investigation of the kinetics of the polymerization of acrylamide in aqueous solutions of sulphuric and acetic acids, initiated by trivalent cobalt ions☆

Abstract The rate of polymerization of acrylamide in aqueous solutions of sulphuric and acetic acids on initiation with trivalent cobalt ions depends on the monomer concentration, and is second order with respect to the monomer and first order with respect to the initiator. This is in good agreement with the reaction mechanism based on the assumption that initiation involves dimeric Co (III) associates, and termination of the growing polymer chains with complex monomer forms of Co (III) aq . An increase in the ratio of the growth and termination constants from 16·6 in sulphuric acid to 52·6 in acetic acid indicates a decrease in the terminating capacity of the Co (III) ions in the case of acetic acid, which is a consequence of the bonding of Co (III) by acetate ions in a low activity complex.