Main events occurring in styrene microemulsion polymerization

A previously presented model with four states (conversion, active and inactive particles and micelles) is further tested with conversion versus time experimental data at 50, 60, and 70C, to recognize the main events occurring in styrene microemulsion polymerization. The S-shaped conversion-with no overprediction- and the bell-shaped active particles number concentration-evidencing diffusive effects at late stages-versus time data, are well described by the proposed model. It was found that: (i) transfer of monomer and surfactant from micelles to particles occurs, (ii) the capture of radicals by micelles is the only cause of particle nucleation, (iii) the rate coefficient of radical-entry-to-micelles is much smaller than that of exit-from-particles, and (iv) no coagulation between particles was detected. The Arrhenius dependency on temperature of the kinetic rate parameters is also reported.