Green Polymer Chemistry: New Living Dithiol Polymerization via Cyclic Intermediates
This paper reports the synthesis and characterization of disulfide polymers obtained by oxidation of 2-[2-(2-sulfanylethoxy)ethoxy]ethanethiol (DODT) using a benign, synergistic system comprised of air, dilute hydrogen peroxide and triethylamine as a catalyst that can be recycled. The dn/dc value of the polymer in THF was determined to obtain absolute molecular weight measurements. High molecular weight disulfide polymers (up to Mn = 250000 g/mol) with polydispersity indices as low as Mw/Mn = 1.15 were obtained. Thermal analysis by DSC and TGA demonstrated that the rubbery polymers had a Tg of −50 °C and began to degrade at 250 °C. Dithiothreitol reduced the polymers back to the original monomeric units in 33 h. MALDI-ToF showed the involvement of oligodisulfide rings (2–14 mers) in the polymerization that displayed the characteristics of a living/controlled polymerization; poly(DODT) was readily chain extended with 1,2-ethanedithiol. The chain extension indicates a class of living polymerization which is governed by radical recombination.
Rosenthal, Emily Q.; Puskas, Judit; and Wesdemiotis, Chrys, "Green Polymer Chemistry: New Living Dithiol Polymerization via Cyclic Intermediates" (2011). Chemical and Biomolecular Engineering Faculty Research. 508.