Kinetics of microemulsion copolymerization of styrene and acrylonitrile in the presence of cosurfactant

The kinetics of microemulsion copolymerization of styrene and acrylonitrile in oil-in-water microemulsions in the presence of n-butanol as a cosurfactant was investigated. Stable and translucent poly(styrene-co-acrylonitrile) latexes were produced. The variations of initiator concentration, polymerization temperature, monomer feed composition and cosurfactant concentration in the microemulsion copolymerization were studied. In addition, the particle size and molecular weights of copolymerization products were characterized. It was found that the rate of copolymerization decreases pronouncedly and the maximum rate was shifted to a lower conversion with an increase of AN concentration in the monomer feed. The presence of n-butanol can lead to a decrease in polymerization rate and an increase in particle size, but a complex effect on the molecular weight of the copolymer. The obtained experimental results were discussed in terms of the nucleation mechanism, the agglomeration of particles and the effect of microemulsion structure. (c) 2005 Elsevier B.V. All rights reserved.