EMULSION COPOLYMERIZATION AND TERPOLYMERIZATION OF STYRENE, METHYL-METHACRYLATE AND METHYL ACRYLATE .2. CONTROL OF EMULSION TERPOLYMER MICROSTRUCTURE WITH OPTIMAL ADDITION PROFILES

An optimal addition profile for the preparation of a chemically homoge neous emulsion terpolymer of styrene, methyl methacrylate, and methyl acrylate was determined using a recently developed model for describin g composition drift in emulsion co- and terpolymerizations, TRISEPS, d escribed in Part I of this series. The model uses recently published s implified equations to describe monomer partitioning and the terminal model for describing terpolymer composition. The optimal addition rate profile was determined from the calculated optimal addition profile w ith a purely empirical and iterative method. With gradient polymer elu tion chromatography (GPEC(R)) the homogeneity and/or heterogeneity of the terpolymers prepared in the iterative series of experiments could be determined and compared to the heterogeneity of the corresponding b atch terpolymer described in Part I. It was shown that a homogeneous t erpolymer could be obtained indicating that the simplified equations f or monomer partitioning and the terminal model for terpolymer composit ion describe the system adequately. It was also shown that GPEC(R) was useful in the determination of the optimal addition rate profile. (C) 1996 John Wiley & Sons, Inc.