Particle nucleation mechanism for the emulsion polymerization of styrene with a novel polyester emulsifier

Abstract

The particle nucleation mechanism in emulsion polymerization of styrene with a novel polyester emulsifier, 5-sulfoisophthalic acid dimethyl ester sodium salt-modified tetracarboxylic acid-terminated polyester (SMTAPE), was investigated. The consumption of SMTAPE micelles was monitored by the measurement of surface tension during the emulsion polymerization. Kinetic studies and emulsifier consumption clearly showed that a continuous nucleation mechanism without Smith-Ewart interval II was characteristic of this system. It was attributed to the high concentration of SMTAPE emulsifier in the polymerization, which led to a large surface area and a vast number of micelles around 10 nm in size that served as the major locus of particle nucleation. A broad particle size distribution was observed throughout the reaction, and the nucleation period lasted well into the reaction until the disappearance of the micelles or the disappearance of monomer droplets.