Synthesis of biodegradable polydisulfides from renewable resources

In this paper, we report the synthesis and preliminary characterization of polydisulfides from a renewable resource. Di-linoleic diol was first converted into dithiol via transesterification of methyl-3-mercaptopropionate catalyzed by Candida antarctica Lipase B (CALB). The kinetics of the reaction was monitored using a newly developed Thin Layer Chromatography method. The dithiol was then polymerized by Reversible Radical Recombination Polymerization (R3P), a scalable "green" polymerization process using triethylamine (TEA) catalyst, aqueous H2O2, and air. 3 wt% H2O2 yielded low molecular weight polymer, while with 30 wt% concentration DL-SS with Mn = 66,400 g/mol and polydispersity of 1.26 was obtained. 800 MHz NMR and Raman spectroscopy did not detect thiol end group signals in this polymer, indicating that it had a cyclic structure. Dithiothreitol degraded the polymer to monomer in two weeks. Full characterization of this new polymer is in progress.