Kinetic studies on emulsion copolymerization of vinyl acetate and acrylics in the batch process

Abstract

The batch emulsion copolymerization of vinyl acetate and acrylic monomers (acrylic acid, methyl acrylate and acrylamide) was investigated at 25 °C with a redox initiator system and a complex emulsifier. The kinetic behaviour of the copolymerization and the structure of the resulting copolymers, as well as the particle size and the number density of the latexes, were studied as a function of the conversion and the reaction time. The results show that the copolymerization process has a three-stage feature under the conditions of the optimum concentration of the initiator and the emulsifier being 0.2 wt% and 2.0 wt%, respectively. During the process, the particle size and the number density change drastically and finally reach limiting values of 120 nm and 2.5 × 10 14mL −1, respectively, for VAc-AA-AM terpolymer. A special mechanism of particle formation is proposed.