Modeling of emulsion copolymer microstructure

A model is developed to describe stages II and III of batch emulsion copolymn., and its predictive capabilities are investigated by application to the system styrene-Me acrylate. The main reaction site is the monomer-swollen polymer particle. Copolymn. rate and copolymer microstructure (molar mass-chem. compn. distribution and sequence distribution at the triad level) are controlled by the local concns. of monomers and free radicals inside the particles. The model accounts for radical absorption and desorption processes, bimol. termination within the particles, and transfer to monomer and chain-transfer agent. Monomer partitioning is described using exptl. detd. relations. The results include rate of (co)polymn., compn. drift, and copolymer microstructure. Apparent reactivity ratios are generally inadequate for describing the course of emulsion copolym