Thermal polymerization of 1,2-dithiane

Thermal polymerization of six-membered cyclic disulfide, 1,2-dithiane (DT) was investigated under various polymerization conditions. The polymerization of DT depends strongly on the monomer concentration, and the polymerization did not proceed at the monomer concentration below 4.0 mol/L in feed. In the polymerization of DT in benzene, the polymerization did not effectively proceed even in the presence of typical radcial initiators. From a kinetic study, overall activation energy for bulk polymerization of DT was estimated to be 22.6 kJ/mol. The polymerization of DT was inhibited by an addition of radical inhibitors, and decreased remarkably in the presence of thiol compounds, indicating that the propagation proceeds by a radical intermediate. The molecular weight of the polymers increased with reaction time. Namely, the cyclic polymer is formed mainly by back biting reaction mechanism during reaction, which is related to the formation of polyeatenane.