Kinetics of isothermal miniemulsion polymerization of 1,6-hexanediol diacrylate

Kinetics of miniemulsion polymerization of 1,6-hexanediol diacrylate (HDDA) was investigated. The particle size of microgel particles remained relatively constant (ca. 270 nm) during polymerization in the temperature range 65-75 °C. The model-fitting method in combination with the model-free method was used to determine the relevant kinetic parameters. The droplet nucleation involved in the miniemulsion polymerization process was satisfactorily predicted by the nucleation Avrami-Erofeyev model {g(α) = [−ln(1 − α)]1/2}. The overall activation energy (E = ca. 75 kJ mol−1) determined by the model-fitting and model-free methods is quite close to the overall activation energy (ca. 80 kJ mol−1) for polymerization initiated by a thermal initiator. By contrast, the conventional model [g(α) = −1/2ln(1 − α)] was incapable of adequately predicting the polymerization kinetic data. The miniemulsion polymerization was characterized by DSC, DLS and TEM.