title: Green polymer chemistry: living dithiol polymerization via cyclic intermediates.
abstract: 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 M(n) = 250000 g/mol) with polydispersity indices as low as M(w)/M(n) = 1.15 were obtained. Thermal analysis by DSC and TGA demonstrated that the rubbery polymers had a T(g) 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.
authors: Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United States.
authors: Emily Q
authors: EQ
authors: Rosenthal
authors: Judit E
authors: JE
authors: Puskas
authors: Chrys
authors: C
authors: Wesdemiotis
mesh_terms: D002384:Catalysis; D004220:Disulfides / Q000737:chemistry*; D004229:Dithiothreitol / Q000737:chemistry; D005019:Ethyl Ethers / Q000737:chemistry*; D005021:Ethylamines / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D010084:Oxidation-Reduction; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: C471080:3,6-dioxa-1,8-octanedithiol; D004220:Disulfides; D005019:Ethyl Ethers; D005021:Ethylamines; D011108:Polymers; D013438:Sulfhydryl Compounds; D006861:Hydrogen Peroxide; D004229:Dithiothreitol; C016162:triethylamine