A study of the mechanism of radiation‐induced polymerization of carbon suboxide

Abstract

AbstractThe γ radiolysis of solid C3O2 at 77 K produces paramagnetic centers of several types. The ESR spectrum constitutes a number of narrow lines with an anisotropic g factor. Some of the centers are photounstable and are lost after optical bleaching. Heating the sample results initially in the loss of photounstable centers and then, in the temperature region in which solid C3O2 undergoes a phase transition (140 K), loss of the centers responsible for the center section of the ESR spectrum. In the temperature region 140–270 K concentration of the centers remained at the level of 1015−1016 g−1. At higher temperatures an intense polymerization of liquid C3O2 followed by a sharp increase in concentration of the paramagnetic centers was observed. It is assumed that in radiolysis at 77 K and on subsequent heating the formation of oligomeric centers in solid C3O2 results in a decreasing probability of their loss. Using a calorimetric technique, we studied the kinetics of the postradiation polymerization of C3O2. Small additions of acetone (cationic inhibitor) brought about the loss of the oligomeric centers and suppressed completely all postpolymerization. The polymerization rate increased with the concentration of the resulting polymer. An autocatalytic character of the process is supposed to be connected with the formation of polymer‐monomer complexes.