Studies on the kinetics of the thermal polymerization of butadiene under high pressure

The thermal bulk polymerization of butadiene was investigated at 323 to 368°K under high pressures in the range of 1100 to 5000kg/cm^2. It was observed that the polymerization reaction was not preceded by an induction period, and the polymer yields increased linearly with the reaction time throughout the comparatively long run. The rate of polymerization was accelerated by increasing the pressure and temperature. From the apparent initial rate, the activation energies, activation volumes and activation entropies were calculated and the following values were obtained ; E=15.1～-19.2kcal/mole, ΔV≠=-8.8～-17.2cm^3/mole and ΔS≒=-38.0～-24.3 e.u. The polymer obtained was insoluble in the ordinary solvents of rubbers, and it was concluded that the polymer is a crosslinked elastic polymer.