Kinetic modeling of free-radical polymerization: a conservational polymerization and molecular weight distribution model

Abstract

A new computational model for free-radical polymerization reactions was developed. The model algorithm is based on the use of an implicit numerical technique to solve for the coupled monomer and total growing polymer concentration differential equations. Determination of the monomer and total growing polymer concentrations ensures that conservation of mass is maintained without the need to solve the large number of differential equations associated with the growing polymer concentrations for each individual chain length. Acceleration of the numerical calculations was achieved by lumping the growing polymer chains into distinct groups. The proposed numerical scheme generates the monomer conversion and a complete molecular weight distribution (MWD) of the growing and dead polymer chains. The current formulation allows for the incorporation of nonidealities, such as the onset of gelation and chain-length-dependent reaction rate coefficients