Benchmarking Stochastic and Deterministic Kinetic Modeling of Bulk and Solution Radical Polymerization Processes by Including Six Types of Factors Two

Bulk and solution radical polymerization is important in daily live. A challenge is still to maximize polymerization rate and control over molecular characteristics such as the molar mass distribution. The last decades have made clear that kinetic modeling is indispensable with originally most focus on deterministic implementations such as the method of moments (MoM) and only more recently promising results for event-driven kinetic Monte Carlo (kMC) simulations that belong to stochastic methods. Computationally, a critical reaction is termination for which one has both distinguishable and nondistinguishable distributed species, which requires a delicate treatment of a stoichiometric factor 2. Proper benchmarking of MoM andkMC simulations demands thus a careful translation of this factor in the Monte Carlo (MC) reaction probabilities. However, limited attention has been paid in thekMC field to the detailed description of such translations. Here, a rigorous derivation is presented on the level of individual termination rates. Emphasis is on termination by recombination and disproportionation. It is highlighted that six types of factor 2 exist that all need to be incorporated with care, including an IUPAC-based one. The consistency is demonstrated by a successful benchmark of essential modeling results for free radical polymerization of methyl methacrylate.