Polymerization of Chloroprene II. Role of Dimers in Thermal Polymerization
Abstract The results in this paper indicate that the bulk thermal polymerization of chloroprene at 35° is in fact a polymerization of chloroprene dimers, and the rate measurements indicate that little or no monomer adds during the propagation process. Since DPPH does not inhibit the dimerization process but inhibits polymerization, it is tempting to conclude that the polymerization is a free-radical addition process, and this idea is to some extent supported by the retarding influence of some other free-radical inhibitors. On the other hand certain features of the polymerization of bulk dimers are difficult to reconcile with a simple free-radical chain mechanism, and it is considered that it would be premature to postulate such a process. It seems likely that monomer participates in the initiation of chains, but there is no unambiguous evidence to suggest how this process might occur. In view of these problems a detailed discussion of possible reactions is hardly relevant at the present stage, and this must await the results of future experimental work.
