Mathematical Modeling of the Grafting of Maleic Anhydride Onto Poly(propylene): Model Considering a Heterogeneous Medium

A kinetic model is developed for the free-radical grafting of maleic anhydride MAH onto PP, taking into account that the reaction medium is heterogeneous due to the incomplete solubility of MAH in the polymer melt. Two different approaches are considered that derive from the limiting cases of very fast mass transfer (equilibrium) and no mass transfer between the two phases. The physical parameters considered in the model include the solubility of MAH in PP and the partition coefficient of the initiator between the two phases. The predictions of the models are in good agreement with experimental data taken from the literature for processes conducted under different conditions.