Homopolymerization and copolymerization of methyl methacrylate in the presence of complexing agents—II. On the mechanism of alternating copolymerization of methyl methacrylate and styrene in the presence of ethylaluminium sesquichloride

Abstract

The kinetics of the photoinitiated copolymerization of styrene and methyl methacrylate in the presence of ethylaluminium sesquichloride, in toluene solution, has been investigated by dilatometry. The data are in agreement with a statistical copolymerization mechanism involving styrene and complexed MMA. The strong alternating tendency is due to an enhancement of the cross-propagation reactions, although homopolymerization may occur in the presence of a large excess of one of the monomers. The ternary complex, if formed, seems not to play a major role in propagation. A reaction scheme is proposed and some of the rate constants have been estimated.