Prediction of the Bivariate Molecular Weight - Long Chain Branching Distribution in Highly Branched Polymerization Systems Using Monte Carlo and Sectional Grid Methods

In the present work, an efficient Monte Carlo (MC) algorithm and a two-dimensional fixed pivot technique (FPT) are described for the calculation of the molecular weight distribution (MWD) for linear polymers (e.g., poly(methyl methacrylate), PMMA) and the bivariate molecular weight−long chain branching distribution (MW−LCBD) for highly branched polymers (e.g., poly(vinyl acetate), PVAc), produced in chemically initiated free-radical batch polymerization systems. The validity of the numerical calculations is first examined via a direct comparison of simulation results obtained by both methods with experimental data on monomer conversion and MWD for the free-radical MMA polymerization. Subsequently, the developed FPT and MC numerical algorithms are applied to a highly branched polymerization system (i.e., VAc). Simulation results are directly compared with available experimental measurements on Mn, Mw and Bn. Additional comparisons between the MC and the FP numerical methods are carried out under different ...