Graduate Theses & Dissertations

Bio-based Polymers from Epoxidized Vegetable Oils Modified by Metathesis
The epoxides of oligomeric self-metathesized soybean oil (MSBO) and cross-metathesized palm oil (PMTAG) and canola oil (CMTAG) containing terminal double bonds were used to produce nonisocyanate polyurethanes (NIPUs) as well as anhydride, amine and thiol-cured epoxies. The synthesized NIPUs displayed metal adhesive properties for CMTAG and MSBO with MSBO being favoured probably due to its plasticizing nature as opposed to CMTAG. The relationship was reversed for the anhydride curing reaction where it was found that CMTAG, due to its lower degree of plasticizing content from the reduced dangling chains, produced higher tensile strengths than MSBO. Both MSBO and CMTAG led to fully cured amine and thiol products that were sticky gels, which prevented physical analyzses of their expected solidified products. PMTAG, due to its low number of reactive groups, was not suitable for the synthesis of these polymers. Author Keywords: Amine-cured epoxy, Anhydride-cured epoxy, Metathesis, Nonisocyanate Polyurethanes, Thiol-cured epoxy
Lipid-derived Thermoplastic Poly(ester urethane)s
Thermoplastic poly(ester urethane)s (TPEU)s derived from vegetable oils possess inferior physical properties compared to their entirely petroleum-based counterparts due to the structural limitations and lower reactivity of the precursor lipid-derived monomers. The present work shows that high molecular weight of TPEUs with enhanced performance can be obtained from lipid-derived monomers via (i) the synthesis of polyester diols with controlled molecular weights, (ii) the tuning of the functional group stoichiometry of the polyester diols and the diisocyanate during polymerization, (iii) the degree of polymerization (iv) the control of the hard segment hydrogen bond density and distribution via the use of a chain extender and (v) different polymerization protocols. Solvent-resistant TPEUs with high molecular weight displaying polyethylene-like behavior and controlled polyester and urethane segment phase separation were obtained. Structure-property investigations revealed that the thermal transition temperatures and tensile properties increased and eventually plateaued with increasing molecular weight. Novel segmented TPEUs possessed high phase separation and showed elastomeric properties such as low modulus and high elongation analogous to rubber. The response of the structurally optimized TPEUs to environmental degradation was also established by subjecting the TPEUs to hydrothermal ageing. TPEUs exhibited thermal and mechanical properties that were comparable to commercially available entirely petroleum-based counterparts, and that could be tuned in order to achieve enhanced physical properties and controlled degradability. Author Keywords: Hydrothermal degradation, Molecular weight control, Polyester diols, Renewable resources, Structure-property relationships, Thermoplastic poly(ester urethane)s

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2009 - 2019
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