Kinetics of radiation polymerization of vinyl benzoate

Abstract

Vinyl benzoate was polymerized by γ-radiation from a cobalt-60 source and the kinetics of polymerization were studied at several temperatures. The results showed that the rate of polymerization was proportional to I^0.66 , where I is the radiation dose rate. The net activation energy for the polymerization reaction, (E_p -1/2 E_t ), was found to be 3.62 kcal, where E_p and E_t are the activation energies for the propagation and termination stages of the reaction. The radical yield measured by the loss of DPPH in the solution after irradiation was G=5.0, while the G (Radical) effective in initiating polymerization was 0.94. The ratio of the rate constants, k² _p/k_t = 5.8 × 10^?4 at 60° and 1.59 × 10^?4 at 25° The rate of polymerization was higher than that of styrene but lower than that of vinyl acetate under comparable conditions.