Study of poly(St/BA/MAA) copolymer latexes with bimodal particle size distribution

Polymer latexes with bi-modal particle size distribution were prepared by introducing small amount of a second seed of polymer particles during the semicontinuous emulsion polymerization of styrene, butyl acrylate and methacrylic acid. The polymerization was investigated by following the variation of the particle size, the size distribution, the number of particles, the surface tension and surfactant surface coverage at different stages of the polymerization process. The results showed that both the size and size distribution can be con trolled by the amount of second polymer particles. The amount of small particles and the partition of monomers consumed for the growth of small particles increased with increasing amount of second polymer particles. It was also demonstrated that small particles grew more quickly than the large ones, but to a limited extent. An introduction df small amount of additional surfactants had Mo significant effect on the particle size and size distribution of both types of particles. (C) 1998 John Wiley & Sons, Ltd.