Green Polymer Chemistry: Synthesis of Poly(disulfide) Polymers and Networks
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| Language: | English |
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University of Akron / OhioLINK
2013
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=akron1386525065 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-akron1386525065 |
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oai_dc |
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NDLTD |
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English |
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Polymers Polymer Chemistry Materials Science polymer polydisulfide disulfide bonds disulfide synthesis reducible bonds biodegradable polymers lipoic acid thioctic acid enzyme catalysis copolymers DODT ethanedithiol networks organogel elastomer Thiokol Thiokol alternative |
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Polymers Polymer Chemistry Materials Science polymer polydisulfide disulfide bonds disulfide synthesis reducible bonds biodegradable polymers lipoic acid thioctic acid enzyme catalysis copolymers DODT ethanedithiol networks organogel elastomer Thiokol Thiokol alternative Rosenthal-Kim, Emily Quinn Green Polymer Chemistry: Synthesis of Poly(disulfide) Polymers and Networks |
| author |
Rosenthal-Kim, Emily Quinn |
| author_facet |
Rosenthal-Kim, Emily Quinn |
| author_sort |
Rosenthal-Kim, Emily Quinn |
| title |
Green Polymer Chemistry: Synthesis of Poly(disulfide) Polymers and Networks |
| title_short |
Green Polymer Chemistry: Synthesis of Poly(disulfide) Polymers and Networks |
| title_full |
Green Polymer Chemistry: Synthesis of Poly(disulfide) Polymers and Networks |
| title_fullStr |
Green Polymer Chemistry: Synthesis of Poly(disulfide) Polymers and Networks |
| title_full_unstemmed |
Green Polymer Chemistry: Synthesis of Poly(disulfide) Polymers and Networks |
| title_sort |
green polymer chemistry: synthesis of poly(disulfide) polymers and networks |
| publisher |
University of Akron / OhioLINK |
| publishDate |
2013 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=akron1386525065 |
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AT rosenthalkimemilyquinn greenpolymerchemistrysynthesisofpolydisulfidepolymersandnetworks |
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1719434868238057472 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-akron13865250652021-08-03T06:20:51Z Green Polymer Chemistry: Synthesis of Poly(disulfide) Polymers and Networks Rosenthal-Kim, Emily Quinn Polymers Polymer Chemistry Materials Science polymer polydisulfide disulfide bonds disulfide synthesis reducible bonds biodegradable polymers lipoic acid thioctic acid enzyme catalysis copolymers DODT ethanedithiol networks organogel elastomer Thiokol Thiokol alternative The disulfide group is unique in that it presents a covalent bond that is easily formed and cleaved under certain biological conditions. While the ease of disulfide bond cleavage is often harnessed as a method of biodegradation, the ease of disulfide bond formation as a synthetic strategy is often overlooked. The objective this research was to synthesize poly(disulfide) polymers and disulfide crosslinked networks from a green chemistry approach. The intent of the green chemistry approach was to take advantage of the mild conditions applicable to disulfide bond synthesis from thiols. With anticipated use as biomaterials, it was also desired that the polymer materials could be degraded under biological conditions.Here, a new method of poly(disulfide) polymer synthesis is introduced which was inspired by the reaction conditions and reagents found in Nature. Ambient temperatures and aqueous mixtures were used in the new method. Hydrogen peroxide, one of the Nature’s most powerful oxidizing species was used as the oxidant in the new polymerization reaction.The dithiol monomer, 3,6-dioxa-1,8-octanedithiol was first solubilized in triethylamine, which activated the thiol groups and made the monomer water soluble. At room temperature, the organic dithiol/amine solution was then mixed with dilute aqueous hydrogen peroxide (3% by weight) to make the poly(disulfide) polymers. The presence of a two phase system (organic and aqueous phases) was critical to the polymerization reaction. As the reaction progresses, a third, polymer phase appeared. At ambient temperatures and above, this phase separated from the reaction mixture and the polymer product was easily removed from the reaction solution. These polymers reach Mn > 250,000 g/mol in under two hours. Molecular weight distributions were between 1.5 and 2.0. Reactions performed in an ice bath which remain below room temperature contain high molecular weight polymers with Mn ˜ 120,000 g/mol and have a molecular weight distribution of around 1.15. However, the majority of the product consists of low molecular weight cyclic poly(disulfide) oligomers. In reactions maintained below 18ºC, the organic components were miscible in the aqueous hydrogen peroxide and a milky emulsion was produced. The polymers were degraded using the disulfide-specific reducing agent, dithiothreitol Poly(disulfide) polymer networks were also synthesized in a two-phase system. Due to the poor solubility of the crosslinker, trimethylolpropane tris(2-mercaptopropionate, organic solvents were required to obtain consistent networks. The networks were degraded using dithiothreitol in tetrahydrofuran. The networks were stable under aqueous reducing conditions.The disulfide-bearing biochemical, a-lipoic acid, was investigated as monomer for the new method of poly(disulfide) polymer synthesis. It was also polymerized thermally and by a new interfacial method that proceeds at the air-water interface. Polymer products were often too large to be characterized by SEC (Mn > 1,000,000 g/mol). A poly(a-LA) polymer sample showed mass loss in aqueous solutions of glutathione at pH = 5.2 which was used to model cytosolic conditions. Poly(a-LA) was decorated with PEG (2,000 g/mol) in an esterification reaction catalyzed by Candida antarctica lipase B (CALB). The decorated polymers were imaged using AFM which revealed branch-like structures.To make new a-lipoic acid based monomers and macromonomers, CALB-catalyzed esterification, was used to conjugate a-lipoic acid to a variety of glycols including: diethylene glycol monomethyl ether, tetraethylene glycol, hexaethylene glycol, and poly(ethylene glycol). The products were verified using NMR spectroscopy and mass spectrometry. 2013 English text University of Akron / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=akron1386525065 http://rave.ohiolink.edu/etdc/view?acc_num=akron1386525065 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |