(163e) Modeling of Chain Sequence Distribution in Thermoplastic Condensation Terpolymers

Linear step growth polymers can be modified to improve their properties by adding a comonomer. In this study, we report a new reaction model for the step growth polymerization of aromatic polycarbonate with a third comonomer such as polysiloxane in a catalyzed melt phase polymerization. Both the kinetic and the statistical chain length distribution models are developed to calculate polymerization rate, molecular weight averages, chain length distribution, and monomer sequence length distribution for AR1A-BR2B-CR3C polymerization system. Simulation results show that the reactivity ratio of end groups, end group concentrations, and the removal rate of condensate have significant effects on the overall degree of polymerization and the monomeric unit sequence distributions. The kinetic model for melt polycondensation is also extended to a solid state polymerization where the presence of the third comonomer can have a strong effect on the crystallinity of the polymer. Through model simulations, we illustrate that the performance of solid state polymerization of the copolycondensation system becomes more complicated than the two-component linear polycondensation system.