Prediction of the Joint Molecular Weight-Long Chain Branching Distribution in Free-Radical Branched Polymerizations

摘要

A novel approach based on orthogonal collocation on finite elements (OCFE) techniques is proposed for the prediction of the joint molecular weight - long chain branching distribution in free-radical polymerization. The OCFE formulation reduces the size of the model, preserves the nature of the balance equations and ensures the closure of the overall material balance regardless of the selected kinetic mechanism. The proposed approach is successfully applied in the free-radical branched polymerization of vinyl-acetate. The OCFE formulation shows high accuracy, when compared to the method of the moments, with improved predictive ability in systems characterized by strong diffusion controlled phenomena and long-chain branching.