NONSTEADY STATE MODEL FOR FREE-RADICAL POLYMERIZATION

The non-steady state theory for the kinetics of free radical polymerization taking no account of gel-effect is reviewed. Considering the facts that the monomer consumption in chain propagation is much higher than that in chain initiation and the rate constant of chain termination is much larger than that of chain propagation or transfer, a few very close approximations are introduced to solve the set of kinetical differential equations of free radical polymerization. The expressions for various molecular parameters, such as the molecular size function, the number- and weight-average degrees of polymerization and the dispersity, are derived. In accord with the non-steady state theory, the curves of free radical decay with reaction time or monomer conversion and the molecular parameters mentioned can be predicted from the reaction conditions. Several numerical examples are given.