Kinetics of miniemulsion polymerization of vinyl acetate with nonionic and anionic surfactants

Abstract

AbstractThe kinetics of miniemulsion polymerization of vinyl acetate, in which nonionic surfactant, Brij‐35 [polyoxyethylene(23) lauryl ether], and hexadecane were used, was investigated. For comparison, experiments were also carried out using an anionic surfactant (sodium lauryl sulfate). The results show that, for all experiments, both distributions for the particle size of the latices and the molecular weight of polymers were unimodal. The effects of surfactant and initiator levels on the particle number and the polymerization rate were studied. For the system using Brij‐35, the power orders for the dependence of particle number on surfactant and initiator concentrations were 1.33 and 0.68, respectively. The polymerization rate was proportional to the 0.38 power of surfactant level and the 0.84 power of initiator concentration. The hydration layer outside the monomer‐swollen particles in the system of nonionic surfactant may exert a retardation effect on the entry of oligomeric radicals into the particles. The result of GPC analysis indicates that the surfactant concentration inversely affects the molecular weight. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1691–1699, 2001