Incorporation of hydroxyl endgroups in vinyl polymer. Part II. Aqueous polymerization of methyl methacrylate initiated by salts or complexes of some metals in their higher oxidation states

Abstract

Hydroxyl endgroups have been incorporated in polymers of methyl methacrylate obtained by initiation with salts or complexes of Mn⁴⁺, Ce⁴⁺, Co³⁺, and Ag³⁺ with the monomer in aqueous solution. Hydroxyl and carboxyl endgroups in the respective polymer samples have been estimated with the help of the dye interaction technique. Initiation with Mn⁴⁺ and Ce⁴⁺ ions in dilute H₂SO₄ medium in the dark at room temperature has been found to incorporate an average of about 2 hydroxyl endgroups per polymer chain. Initiation with potassium trioxalato cobaltate (III) complex has been carried out both in the dark and in the presence of ultraviolet light at room temperature, and both carboxyl and hydroxyl endgroups have been characterized in the polymers formed. An average total of 1 endgroup (both COOH and OH combined) per polymer chain has been obtained in case of photoinitiation, and about 2 per polymer chain in the case of thermal initiation in dark. Polymerization in the dark at room temperature has been carried out in neutral medium with ethylene dibiguanidinium nitrate complex of tripositive silver as the initiator, and an average of 2 hydroxyl endgroups per polymer chain has been found to be incorporated in the process.