Peculiar initiation behavior of azo-initiators in allyl polymerization

On the course of a series of studies concerned with the elucidation of the allyl polymerization mechanism, the bulk polymerization of allyl benzoate was carried out using a large amount of 2,2′‐azobis(isobutyronitrile) (AIBN) and dimethyl 2,2′‐azobis (isobutyrate) (DMAIB). Incidentally, the initial rate of polymerization initiated by DMAIB was more than two times higher than that by AIBN, although the decomposition rate constants of AIBN and DMAIB are almost same at 80 °C. This peculiar initiation behavior of azo‐initiators is discussed to clarify the initiation mechanism in allyl polymerization, especially focused on the competitive contribution to the initiation and termination reactions by primary radicals.