Type of Document Master's Thesis Author Rosu, Cornelia Author's Email Address email@example.com URN etd-03252010-132523 Title Recent Advances in Glylons Science Degree Master of Science (M.S.) Department Chemistry Advisory Committee
Advisor Name Title Russo, Paul Committee Chair Daly,William Committee Member Negulescu, Ioani Committee Member Zhang, Donghui Committee Member Keywords
- tree rings
- liquid crystals
Date of Defense 2009-10-28 Availability unrestricted AbstractA variety of sugar- based polyamides called glylons were synthesized by using different pathways. The sugar- units were derived from D- glucaric acid and D-galactaric acid. Glylons D-glucaric- based with pendant free hydroxyl groups showed a low solubility in organic solvents, due to hydroxyl preference to form strong intra- and intermolecular H- bonding. To minimize these interactions an acetalation reaction was performed. Monoacetalated D-glucaric-based po-lymers exhibited a better solubility in a broader range of solvents but the residual hydroxyl groups favored aggregation. Completely blocked bis-acetalated galactaric-based glylons are so-luble in a broad range of solvents including toluene/methanol mixtures. Deprotection reaction performed with hydrofluoric acid led to the initial problem of solubility.
A combination of techniques such as FTIR, 1H, 13C, COSY NMR, MALDI-TOF, GPC, DSC and TGA were employed to characterize the synthesized glylons. The course of the poly-meri¬zation reaction was monitored with FTIR and NMR. Cyclic and linear species were identi-fied with MALDI-TOF mass spectrometry. The cyclization leads to premature termination and only low molecular weight glylons can be isolated. The ration linear to cyclic varies for glylons with both odd-carbon numbered and even-carbon numbered diamines. Glylons bearing pro¬pylene di¬amine units have a higher ratio of linear species when compared with glylons having hexame-thylene diamine units. These conformers were identified also by GPC, DSC and TGA. Furthermore, GPC technique suggests the existence of a higher molecular weight polymer frac-tion. Thermal analysis pointed out that glylons are low crystalline polymers.
Organized patterns resembling tree-rings were found to form in solutions of deprotected glylons (gly-6, 6 and GalEt_unpr) in NMMO monohydrate and BMIMCl. The investigation of their morphologies was performed with optical, polarized light and confocal microscopy,small/wide angle light scattering as well. The thickness of the rings was noted to be highly influenced by the concentration, temperature, viscosity and the surface available for growth.
In dimethylsulfoxide deprotected galactaric glylons were found to form gels.
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