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 wi 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 wi tends to increase in the course of polymerization transformation in agreement with the wi = 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 wi = 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 wi remains invariable in the course of polymerization transformation.