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

The particle nucleation mechanism in emulsion polymerization of styrene wit h a novel polyester emulsifier, 5-sulfoisophthalic acid dimethyl. ester sod ium salt-modified tetracarboxylic acid-terminated polyester (SMTAPE), was i nvestigated. The consumption of SMTAPE micelles was monitored by the measur ement of surface tension during the emulsion polymerization. kinetic studie s and emulsifier consumption clearly showed that a continuous nucleation me chanism without Smith-Ewart interval II was characteristic of this system. It was attributed to the high concentration of SMTAPE emulsifier in the pol ymerization, which led to a large surface area and a vast number of micelle s around 10 nm in size that served as the major locus of particle nucleatio n. A broad particle size distribution was observed throughout the reaction, and the nucleation period lasted well into the reaction until the disappea rance of the micelles or the disappearance of monomer droplets. (C) 2001 Jo hn Wiley & Sons, Inc.