RATE OF EMULSION COPOLYMERIZATION OF STYRENE AND ACRYLONITRILE

Abstract

The emulsion copolymerization of acrylonitrile and styrene was carried out. The rate of reaction, the number of polymer particles and the compositions of copolymer were determined experimentally under various initial monomer concentrations, volume fractions of monomers and emulsifier concentrations.
A mathematical model of this copolymerization system, in which one monomer is hydrophilic and the other is hydrophobic, has been derived based on the assumptions that the reaction takes place inside polymer particles and that there exists a partition equilibrium of acrylonitrile between the aqueous and the oil phases. The Lewis-Mayo equation was modified by the introduction of the parameter B, the ratio of concentrations of two monomers in polymer particles. It was shown that B is a function of a, the partition coefficient of acrylonitrile, and the monomerwater phase ratio. The Lewis-Mayo equation was solved numerically, and the calculated results coincided well with the observed ones.