The mechanism of propagation in free-radical copolymerization

A brief overview of free-radical copolymerization kinetics is presented. Recent developments have highlighted the shortcomings of the terminal (or Mayo–Lewis) model. However, for many practical reasons, approximate models are useful for assisting our understanding of any given copolymerization reaction and allowing comparisons with the vast database on copolymerization reactions. Terminal model reactivity ratios have limited meaning, so it may be imprudent to use these values as a quantitative measurement of radical reactivity. Presently, experimental limitations restrict the amount of information that can be obtained by models being fitted to composition or propagation rate data; therefore, the direct measurement of radical reactivity is required together with high-level quantum calculations.