Synthesis and Characterization of Poly(1,2-dithiane)

Polymerization of 1,2-dithiane (DT) and the characterization of the polymer were investigated. Bulk polymerization of DT proceeded readily without initiators above the melting point of DT, giving a polymer in high yield. The polymerization of DT was strongly affected by the presence of small amounts of thiols. The molecular weight of polymers obtained from the polymerization of DT could be controlled by the addition of benzyl mercaptan (BM). The 13C and 1H NMR spectra of the poly(DT) suggest that the poly(DT) has a macrocyclic structure containing disulfide bonds in the main chain, in contrast to the linear polymers that were obtained from polymerization of DT in the presence of thiols. The poly(DT) obtained from polymerization of DT was characterized by the interconversion between thiol and disulfide bonds, thermal properties, dynamic viscoelasticity, stress−strain test, solubility, and photodegradation of the poly(DT) and was found to have unusual properties. In the polymerization of DT in the presence of the cyclic poly(oxyethylene) (CPO), the product included a catenane structure of cyclic poly(DT) and CPO entangled with each other. From the results obtained in this study, we presume that the poly(DT) obtained from polymerization of DT includes a polycatenane structure.