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dc.contributor.authorWilson, Benn Charlesen_US
dc.date.accessioned2005-03-01T19:43:29Z
dc.date.available2005-03-01T19:43:29Z
dc.date.issued2004-12-06en_US
dc.identifier.urihttp://hdl.handle.net/1853/4918
dc.description.abstractAliphatic polyesters such as polycaprolactone and polylactide have received more attention in recent years for their use in biomedical applications because of their biodegradable nature. These polymers are often synthesized using homogeneous metal complexes. Unfortunately, using homogeneous metals as catalysts leads to metal contamination in the product polymer, a result which is highly undesirable in a polymer intended for biomedical use. More recent work has shown that these polymers can be synthesized using homogeneous metal-free complexes. These catatlysts are generally less active than metal catalysts, and although they do not contaminate the polymer with metal residue, they are still difficult to recover and hence recycle for further use. In this work, we attempted to create a metal-free, silica-supported catalyst for use in the synthesis of polycaprolactone or polylactide. Ultimately, n-propylsulfonic acid-functionalized porous and nonporous silica materials are evaluated in the ring-opening polymerization of epsilon-caprolactone. All catalysts allow for the controlled polymerization of the monomer, producing polymers with controlled molecular weights and narrow polydispersities. Polymerization rates are low, with site-time-yields generally one to three orders of magnitude lower than metal-based systems. The catalysts are easily recovered from the polymerization solution after use and are shown to contain significant residual adsorbed polymer. Solvent extraction techniques are useful for removing most of the polymer, although the extracted solids are not effective catalysts in recycle experiments. These new materials represent a green alternative to traditional metal-based catalysts, as they are recoverable and leave no metal residues in the polymer.en_US
dc.format.extent281193 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectOrganic catalystsen_US
dc.subjectMetal free catalysts
dc.subjectBiodegradable polymers
dc.subjectLactide
dc.subjectCaprolactone
dc.subjectSilica-supported catalysts
dc.subject.lcshSilicaen_US
dc.subject.lcshPolymers in medicineen_US
dc.subject.lcshCatalystsen_US
dc.subject.lcshBiocompatibilityen_US
dc.titleSilica-Supported Organic Catalysts For The Synthesis Of Biodegradable Polymersen_US
dc.typeThesisen_US
dc.description.degreeM.S.en_US
dc.contributor.departmentChemical Engineeringen_US
dc.description.advisorCommittee Chair: Dr. Chris Jones; Committee Member: Dr. Joseph Schork; Committee Member: Dr. Marcus Wecken_US


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