Phase equilibria in the systems used for vinyl acetate micro-emulsion polymerization

Abstract

Phase behavior of vinyl acetate-water system in the presence of various surfactant-cosurfactant mixtures was studied. The surfactants used were sodium dodecyl sulfate and ethoxylated nonylphenol with 3 and 30 moles of ethylene oxide, respectively. Alcohol cosurfactants from methanol to 2-ethylhexanol were employed. The effect of salinity (i.e., 1% wt. NaCl) was also considered. The most efficient surfactant in reducing the multiphase zone was sodium dodecyl sulfate. For NP-30 surfactant the micro-emulsion increases with surfactant concentration and consurfactant hydrophilicity. The electrolyte increases the multiphase area. Structure investigation showed a cosolubilized system rather than a micro-emulsion to be present in the isotropic phases.