Modeling the Reaction Event History and Microstructure of Individual Macrospecies in Postpolymerization Modification

For postpolymerization modification, a novel kinetic Monte Carlo (kMC) modeling strategy for the description of the reaction event history and the evolution of the microstructure of individual macrospecies with a complex topology is presented. The kMC model allows the kinetic analysis of free radical induced grafting of vinyl monomers onto polyethylene (PE) chains, assuming isothermal conditions and perfect macromixing and accounting for diffusional limitations on the microscale. Not only average characteristics such as the monomer conversion, grafting selectivity and yield, but also the chain length distribution (CLD) of all macromolecular species types, the average from/to grafting and cross-linking density, the number of grafts and cross-links per individual macromolecule, the chain length of every graft, and the CLD of the grafted chains are calculated. Under typical grafting conditions, depropagation and diffusional limitations cannot be ignored. The functionalization occurs mainly on those macrospecies in the PE-CLD with a high mass concentration. (C) 2017 American Institute of Chemical Engineers