Semi-batch emulsion copolymerization of styrene and butyl acrylate for production of high solids content latexes: Experiments and mathematical model

Abstract

Polymer latexes with high solids content exhibit several advantages such as lower costs of transport and storage and shorter drying and film formation times. To keep the apparent viscosity at satisfactory levels, the particle size distributions should be either broad or multimodal. In the present work, the production of high solid content latexes by emulsion copolymerization of styrene and butyl acrylate was studied in a semi-batch process in which the nucleation of a second population of particles is promoted by the instantaneous (shot) feeding of an additional charge of emulsifiers. Latexes of about 64 wt% of solids with bimodal particle size distributions and reasonably low apparent viscosity were produced. A representative mathematical model for the copolymerization processes that accounts for the changes in the particle size distribution that occurred in the process is presented, tested and validated with the experimental data measured during the experiments.