Penultimate unit effect in the copolymerization of alkyl methacrylates and styrene

Abstract

Kinetics of bulk copolymerization of styrene and alkyl methacrylates, namely, ethyl, isobutyl and n-nonyl methacrylate have been investigated at 60°C, and the extent of diffusion-controlled termination in these systems has also been checked. Rate-composition curves reveal that addition of a small amount of styrene in pure alkyl methacrylates markedly reduces the rate of polymerization, the effect becoming more important as the chain length of the ester group is increased. With higher alkyl methacrylates, the position of the minima in the curves shifts towards a lower concentration of styrene in the feed. The applicability of Arlman's theory on the variation of the Φ-factor with monomer feed composition has been examined.