Radiation‐induced copolymerization of acrylonitrile with methyl methacrylate

AbstractRadiation‐induced copolymerization of acrylonitrile (1) with methyl methacrylate (2) was investigated over a wide range of temperatures. The rate of copolymerization decreased linearly with the molar concentration of acrylonitrile in the liquid‐state copolymerization at 15°C. On the contrary, the rate of copolymerization increased linearly with the concentration of acrylonitrile in the solid state at −78°C. The rate of copolymerization was proportional to the square root of the dose rate in an equimolar mixture of the monomers at 15°C. The apparent activation energy of the copolymerization was 4.62 kcal./mole in an equimolar mixture of the monomers. Monomer reactivity ratios r1 and r2 were determined from the experiments at various temperatures. From these results, the differences of the activation energies in the propagation steps were obtained as follows: E‡11 − E‡12 = 2.76 kcal./mole; E‡22 − E‡21 = 2.58 kcal./mole.