Radiation Induced Cyclopolymerization of Acrylic Anhydride

Abstract

Radiation-induced solution and bulk polymerization of acrylic anhydride were carried out over a wide range of temperature, for the purpose of studying the effects of temperature, phase, conversion, and initial monomer concentration on the degree of cyclization of the polymer obtained. The degree of cyclization increases with increasing conversion and temperature, and decreases with increasing initial monomer concentration. The degree of cyclization of the polymer formed in solid state at -78°C is similar to that of the polymer obtained in toluene solution at the same temperature. But the polymer formed in solid state is crosslinked. The determination of the residual unsaturation of the polymer by bromometry makes it possible to evaluate the ratio k_p/k_c of the rate constant of vinyl propagation and that of cyclization; for solution polymerization in toluene at 30°C, this ratio is equal to 0.09. Similarly, the difference between the activation energies of vinyl propagation and cyclization is evaluated to be 2.3kcal/mol for solution polymerization in toluene, and 4.7 kcal/mol for bulk polymerization in liquid state, respectively.