Simulation of particle growth in the dispersion polymerization of styrene:The termination rate constant in particles

A model is proposed for simulating the particle growth in the dispersion po lymerization of styrene in ethanol. The model is based on the following ass umptions: (i) the termination reaction in an ethanol-phase and the chain-tr ansfer reactions in the ethanol-phase and particles can be neglected, (ii) the mean volume of the radicals captured by particles is approximately equi valent to that of monomeric radicals, and (iii) the termination rate consta nt in particles is beta (gel) times that of the ethanol-phase. The experime ntal results of the conversion, the particle diameter and the particle numb er measured at the reaction time of 2 h were used to determine the initial conditions. When the termination rate constant in particles was taken to be about 1/130 of that of the ethanol phase, the calculation results of the c onversion and the particle diameter were in good agreement with the experim ental data.