Modeling multiradicals in crosslinking MMA/EGDMA bulk copolymerization

In the present work, a kinetic model of crosslinking free-radical copolymerization based on multidimensional population balances and accounting for multiradicals is developed. The model is applied to the simulation of bulk copolymerization of methyl-methacrylate (MMA)/ethylene-glycol-dimethacrylate (EGDMA). A literature criterion proposed to elucidate the model type best suited for a given system (i.e., with or without MRs) is extended to the industrially relevant case of diffusion limited systems. Moreover, a master plot for the system under investigation is proposed: given the reaction recipe, the error on the gel point prediction employing the monoradical assumption is identified, thus allowing more conscious model selection. The relevance of active chains bearing multiple active sites (multiradicals) in the MMA/EGDMA system can be appreciated estimating the relative error on the gel point prediction vs. crosslinker content, when comparing the predictions of two models, one accounting and the other neglecting such species. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.