High temperature semibatch free radical copolymerization of butyl methacrylate and styrene

High temperature starved feed semibatch solution polymerization is used to produce acrylic resins for automotive coatings. These operating conditions promote secondary reactions that have a strong impact on polymerization rate and polymer molecular weight (MW). This study experimentally investigates high temperature semibatch copolymerization of butyl methacrylate and styrene, a system subject to the combined effect of depropagation and penultimate propagation kinetics. A mechanistic model including these complexities is constructed in Predic (R). With the termination rate coefficient fit to the semibatch results and all other coefficients taken from independent experiments, the model provides good predictions of monomer conversion and MW. Various representations of copolymer termination kinetics from the literature are compared to the values fit from experiment.