Mechanistic Insights into Transfer-Dominated Branching Radical Telomerization through Kinetic Monte Carlo Simulation

Transfer-dominated branching radical telomerization (TBRT) is a recently described technique that enables the synthesis of step-growth-like polymers by free-radical polymerization of multivinylic monomers in the presence of high amounts of a chain transfer agent. This work explores the use of Kinetic Monte Carlo (KMC) simulation to describe the polymerization process and to investigate the nature of the complex microstructure of polymers produced by TBRT. The predictions by KMC confirm a branched, yet largely homogeneous structure, with the network microstructure determined by the relative rate of the chain transfer reaction. In agreement with the experimental evolution of the molar mass distribution during the reaction of ethylene glycol dimethacrylate and dodecanethiol, it was found that initially the polymer is formed of low molar mass primary chains formed by chain transfer. As the reaction progresses, both model and experimental results suggest that these chains are incorporated into larger structures to generate long chains that have a polyester-like backbone. It is shown that the KMC method gives unique access to structural information about the polymer, and it is hoped that in future this can be used to target specific architectures.