Polymerization of methacrylonitrile induced by ionizing radiation

The polymerization of methacrylonitrile induced by ionizing radiation was investigated in bulk in the temperature range of 40 to −196°C. It was found from this investigation that two different polymerization mechanisms can exist in the polymerization under the same conditions at different temperature regions. The two different polymerization phenomena at room and at low temperature regions proceed by two different mechanisms: ionic and radical. It was found that the apparent activation energy in bulk polymerization is 6.3 kcal./mole in the 40 to −10°C. range and ca. 0.3 kcal./mole for polymerization initiated by high energy radiation in the −40 to −196°C. range. The effects of additives in the polymerization at both temperature regions were investigated. The viscosity of the polymer was measured in acetone solution at 25°C. and the infrared spectrum of the polymer was also measured. The authors believe from these experiments that the polymerization at room temperature proceeds by a radical mechanism and that the polymerization in the solid state at low temperature proceeds by an ionic mechanism. An important possibility was emphasized that a stereoregular ionic polymerization would be possible even in solid state of monomer by ionizing radiation.