Modeling emulsion copolymerization: Crosslinking kinetics

The authors' kinetic models for network formation in free radical polymerization both for pre‐ and post‐gelation periods are re‐examined and extended to include high mole fractions of divinyl monomer. Network formation in free radical polymerization is a non‐equilibrium process, namely, it is kinetically controlled, and therefore, the crosslinking density of a primary polymer molecule depends on its history. The crosslinking process is responsible for a distribution of crosslinking density with crosslinking density a function of the birth time of a primary polymer molecule. The crosslinking density distribution is an important feature of network formation in free radical polymerization. Under special rather limiting conditions the present kinetic models reduce to Flory's theory of network formation in which an equilibrium system is assumed. These kinetic approaches provide great insight into the phenomena of network formation, and they can readily be applied to emulsion polymerization.