Effect of short-chain alcohols on the oil-in-water microemulsion polymerization of styrene

The influence of short-chain alcohols, l-butanol (C4OH), 2-pentanol (C5OH) and 1-hexanol (C6OH), on the formation of oil-in-water styrene microemulsions and the subsequent free-radical polymerization was studied. Sodium dodecyl sulfate was used as the surfactant. The overall performance of C4OH as the cosurfactant is quite different from C5OH and C6OH. The range of the microemulsion region in decreasing order is C4OH > C5OH > C6OH. The primary parameters selected for the microemulsion polymerization study were the concentrations of cosurfactant and styrene. Only a small fraction of microemulsion droplets initially present in the reaction system can be successfully transformed into latex particles and the remaining droplets serve as a reservoir to supply the growing particles with monomer. Limited flocculation of latex particles also occurs during polymerization and the degree of flocculation is most significant for the C4OH system.