Gamma radiation-initiated polymerization of styrene at high pressure. IV. Emulsion polymerization with nonionic emulsifier

The effects of pressure, irradiation dose rate, and emulsifier concentration on the rate of polymerization of styrene emulsions stabilized with a nonionic surfactant, Teric GX13, were investigated. Results differed from those previously obtained with anionic surfactants and did not follow Smith–Ewart kinetics. The controlling influence of the surfactant at the particle–water interface on the reaction was demonstrated and results could be interpreted in terms of the Medvedev equation. Using this equation, we determined a value for the activation volume for chain propagation, ΔV, as ?18.7 cm³ mol^?1. This value is the same as that for pure styrene and emulsions that follow Smith–Ewart kinetics.