γ-radiation-induced ionic polymerization of pure liquid styrene. II

In this second paper of the series we present additional evidence that the γ-radiation-induced polymerization of very pure, ultradry styrene exhibits kinetics that can best be explained as due to one or more ionic processes, depending on the dryness of the sample. We have shown the effect of the various steps in the drying procedure on the observed kinetics, and we have described a preparative procedure which yields good reproducibility among independently prepared samples. Under these conditions, the rate of polymerization is proportional to the 0.70 power of the dose rate at 0°C.; there appears to be no wall effect; and the temperature coefficient for the process appears to be a complicated function, most probably a small negative value over the range of temperature (0–50°C.) and dose rates (～10³–10⁵ rad/hr.) covered in this study. The maximum G value for disappearance of monomer which we have observed is of the order of 6 × 10⁵ molecules of monomer/100 e.v. at 0°C. and a dose rate of 2 × 10³ rad/hr.