dc.contributor.advisor | Kılıç, Soner | |
dc.contributor.author | Tunç, İlknur | |
dc.date.accessioned | 2016-07-01T11:00:23Z | |
dc.date.available | 2016-07-01T11:00:23Z | |
dc.date.issued | 2004 | |
dc.identifier.uri | http://hdl.handle.net/11693/29488 | |
dc.description | Cataloged from PDF version of article. | en_US |
dc.description.abstract | In this project, 1, 2, 3, and 4-armed poly(L-lactide)s (PLs) were synthesized by
ring opening polymerization (ROP) of L-lactide in the presence of an alcohol and
stannous dioctoate. The resultant polymers were characterized by Gel Permeation
Chromatography (GPC) and Nuclear Magnetic Resonance spectroscopy (NMR). The
dynamic thermal degradation of these polymers was studied by Thermogravimetric
Analyzer (TGA). In order to study the effect of end-groups on thermal degradation,
the synthesized OH functional polymers were reacted with succinic anhydride to
obtain COOH functional polymers. It was found that the thermal degradation
temperatures of acid functional polymers are 25oC higher than those of OH functional
ones at the same heating rate. Therefore, they are more stable than the OH
counterparts. The average activation energies (Ea) of thermal degradation of OH and
COOH functional polymers were also determined using Ozawa’s and Reich’s
approaches. According to Ozawa’s approach, Ea values of OH functional PLs
changing between 73.7 kJ/mol and 76.5 kJ/mol while Ea values of COOH functional
PLs changing between 77.9 kJ/mol and 81.8 kJ/mol. According to Reich’s approach,
Ea values of OH functional PLs changing between 67.8 kJ/mol and 70.7 kJ/mol while
Ea values of COOH functional PLs changing between 72.2 kJ/mol and 75.8 kJ/mol.
Crystallinities of resultant PLs were characterized by X-Ray Diffraction (XRD). From
the diffraction line broadening, it was concluded that the OH and COOH functional
PLs have the same crystalline structure. However, some differences exist between the
crystallite sizes of linear and multi-arm PLs as well as PLs with OH and COOH endgroups. | en_US |
dc.description.statementofresponsibility | Tunç, İlknur | en_US |
dc.format.extent | xii, 77 leaves, illustrations | en_US |
dc.language.iso | English | en_US |
dc.rights | info:eu-repo/semantics/openAccess | en_US |
dc.subject | Poly(L-lactide) | en_US |
dc.subject | Crystallite Size | en_US |
dc.subject | Activation Energy | en_US |
dc.subject | Ozawa’s and Reich’s Approaches | en_US |
dc.subject | Thermal Degradation | en_US |
dc.subject.lcc | QD381 .T86 2004 | en_US |
dc.subject.lcsh | Macromolecules. | en_US |
dc.title | Synthesis, characterization, and thermal degradation of Poly(L-Lactide)s | en_US |
dc.type | Thesis | en_US |
dc.department | Department of Chemistry | en_US |
dc.publisher | Bilkent University | en_US |
dc.description.degree | M.S. | en_US |
dc.identifier.itemid | BILKUTUPB083095 | |