Kinetic modeling of methyl methacrylate free-radical polymerization initiated by tetraphenyl biphosphine

This study presents a semi-empirical kinetic model for the prediction of mo nomer conversion and average molecular weight during pseudo-living radical polymerization of methyl methacrylate with tetraphenyl biphosphine as the i nitiator in bulk, using UV light as the energy source. The model incorporat es the chain-transfer to the initiator. which has been shown to be an impor tant reaction for controlling the molecular weight of formed polymers. To s olve the set of proposed kinetic equations the method of statistical moment s was employed. The kinetic parameters estimated by fitting the initiator c onversion data and monomer conversion data were used for modeling the molec ular weight profiles, which were in a fair agreement with the experimentall y measured average molecular weights. The pseudo-living radical polymerizat ion scheme is characterized by having reversible termination steps. The pro posed circular reaction mechanism was lumped in the empirical power-law rea ction rate expression, which seemed to be successfully employed in the mode l development. The modeling results may be used for the characterization of the polymerization process studied as well as for the prediction of the po lymerization behavior at monomer conversions up to 30%. (C) 2001 Elsevier S cience Ltd. All rights reserved.