Thermal polymerization of styrene: New data on the conversion dependence of the initiation rate

With the aid of new acceptors of free radicals usable at high temperatures (T > 100°C), the rate of initiation w _i has been measured experimentally for the thermal polymerization of styrene at 122.5°C in a wide range of conversions C = 0–80%. It has been shown that the value of w _i tends to increase in the course of polymerization transformation in agreement with the w _i = f(C) relationship calculated from the kinetic data on the thermal polymerization of styrene in the absence of counters of free radicals. Hypothetical reasons for this non-trivial tendency have been formulated. The experimental dependence w _i = f(C) has been measured for the first time and has been invoked to refine currently available mathematical models for the thermal polymerization of styrene that assume that w _i remains invariable in the course of polymerization transformation.