Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 43 for “"Polyols"”.
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Polyols made from vegetable oil and their applications
… value # 78, SBO/allyl alcohol polyols. These polyols have reasonable properties in terms of the hydroxyl content, acid value and are produced through inexpensive means. The applications of the above synthesized materials have been studied in part in making of foams, ion exchange …
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Homogeneous and heterogeneous rhenium catalysts for sustainable transformations of polyols, alcohols, and amines
<p>Biomass-derived molecules, such as sugar polyols and lignin, are promising feedstock for making small and useful organics (SUO) and high value-added organics (HVO). However, the high oxygen to carbon ratio (C:O ≈ 1) prohibits the direct use of biomass-derived molecules as energy carriers and …
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Catalytic osmylation of dienes : mechanistic studies and applications to the stereoselective synthesis of polyols
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1991.
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Phosphate Tether-mediated Approaches for the Syntheses of Complex Polyols, Natural Products and Related Analogs
The development of new synthetic strategies, allowing for efficient asymmetric syntheses of complex biologically active natural products, natural product analogs, and pharmaceutical agents is a long-standing goal for synthetic chemists. In particular, divergent strategies that allow the generation …
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Selective dehydration of polyols over solid acids and metal-acid bifunctional catalysts: Towards a catalytic toolbox for rational catalyst design
… to handle selective oxygen removal.</p> <p>Polyols are a particular class of compounds which consist of a carbon backbone and multiple hydroxyl groups. Most polyols are derived from biorenewable sources, ranging from glycerol, which comes from triglycerides, up to 6-carbon sugar alcoohols. …
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Synthesis of environmentally-friendly polyurethane dispersions based on soybean oil- derived polyols and their applications in advanced water-based and uv-cure coatings
<p>Polyurethane dispersions (PUD) have established themselves as most versatile polymeric binder in coating, adhesive, sealant, and elastomer industries. Like any other polymers, PUDs also have certain limitations, such as hydrolytic stability, water resistance, and oil resistance. In order to …
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Polyurethane foams containing renewable castor oil replacement
… polyurethane foams are made from petroleum-based polyols and isocyanates. Due to the shortage of fossil resources, renewable biobased materials are studied as alternatives to petroleum. In this project, castor oil was chosen as a renewable biobased polyol in order to replace the nonrenewable …
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Responsive molecules: 1. Redox-responsive quadruple hydrogen bonding unit 2. Crosslinked dendronized polyols for brighter and more stable dyes 3. Photoresponsive proton gate for cross-membrane transfer
This thesis reports studies in three separate contexts that show how responsiveness can be introduced or tuned in different molecular systems thus providing desirable control over material properties. In Chapter 2, we designed a new quadruple hydrogen-bonding module (eDAN). The binding affinity of …
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Design,formulation and synthesis of UV/Thermal dual cure, bio-based polyurethane coatings
… have been synthesized using soybean oil based polyols (> 80% bio-renewable content) as a primary component. To overcome some of the limitations associated with soft and flexible structure of soy-based polyols, the resin has been designed with two unique set of functional groups –OH and …
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Investigation of the autocatalytic Cu(II) reduction processes in the systems with natural polyhydroxylic compounds as ligands /
This work investigates polyols – glycerol and sucrose – as an alternative ligand for electroless copper plating systems with reducer formaldehyde. Natural polyols are environmentally friendly, easily bio-degradable materials, but has not been studied enough for suitability for copper plating …
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Isolation and characterization of the (NAD(P)-independent)polyol dehydrogenase from the plasma-membranes of gluconobacter oxydans ATCC strain 621
… large number of different polyhydroxy alcohols (polyols). These oxidations are catalyzed by constituitively synthesized plasma-membrane bound dehydrogenases. These bacteria would have to expend much energy to constituitively synthesize a separate substrate-specific dehydrogenase for each polyol …
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Interactions of biomass derived oxygenates with heterogeneous catalysts in aqueous and vacuum environments
… to understand how two and three carbon polyols interact with metal oxide surfaces, to elucidate the role of various surface sites on polyol-metal oxide interactions, and to discover the surface species of kinetic importance in aqueous phase reforming reactions of biomass molecules. …
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Catalytic Activity of Tungsten-dioxo and Tungsten-diimido Complexes
… carbon commodity chemicals from biomass derived polyols. This dissertation details the design, development, and synthesis of d0 dioxo-W(VI) complexes bearing a bulky phenolate ligand which were active towards the dehydration and deoxydehydration of polyols. The selective homogeneous dehydration …
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Cold-acclimation of the wood cockroach <i>Cryptocercus punctulatus</i> (Scudder) (Dictyoptera: Cryptocercidae)
… undetectable levels in the summer. To date, five polyols have been reported as occurring in insect hemolymph. They are: glycerol, sorbitol, mannitol, erythritol, and threitol. There is one report of the occurrence of an unidentified 5-carbon polyol, possibly either arabitol or ribitol from whole …
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Synthesis and Characterization of Hydrophilic-Hydrophobic Poly (Arylene Ether Sulfone) Random and Segmented Copolymers for Membrane Applications
… modified to obtain poly(arylene ether sulfone) polyols with aliphatic hydroxyethyl terminal functionality. The hydroxyethyl-terminated oligomers and α-ω-hydroxy-terminated PEO were chain extended with a diisocyanate to obtain polyurethanes. Compositions with high poly(arylene ether sulfone) …
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Polyol induced extraction (PIE) of water from organic solvents
… In a quest for an MSA, our investigation reveals polyols as a new class of MSAs. It is observed that when a polyol such as glycerol, sorbitol, erythritol, xylitol, Isomalt® or maltitol is added to a mixture of ACN-water, the ACN separates out of the mixture to form a new immiscible upper phase. …
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A kinetic investigation of boronic acid/diol interactions and pattern-based recognition of [alpha]-chiral carboxylates
… boronate esters with of 1,2- and 1,3-diols, polyols, catechols, and α-hydroxycarboxylic acids, boronic acids have found applications spanning from lipid transport to Hydrogen fuel cells. The majority of the work presented in this dissertation will be aimed at gaining a better understanding of …
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Morphology of water-blown flexible polyurethane foams
… successfully incorporated the trifunctional polyols into a network indicating a high degree of polymerization for the hydroxyl-isocyanate reaction. Unreacted isocyanate is present in the foams a month after curing. It is believed to be trapped in the large urea aggregates. WAXS patterns of …
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Renewable Source Thermoplastics
… meant to directly compete with petroleum based polyols as a drop-in replacement in thermoplastic polyurethanes. A model kinetic study was performed to compare relative reactivity of the Cerenol polyol to standard four carbon repeat unit petroleum-based polyol ether (PTMEG). A Mettler Toledo real …
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Investigations of Colorado potato beetle [Leptinotarsa decemlineata (Say)] pest management including: sampling strategies for insecticide resistance detection, development of a knowledge-based expert system and the physiology of cold tolerance
… for cold tolerance. Two polyhydric alcohols (polyols) were isolated in the hemolymph of Colorado potato beetle using high performance thin layer chromatography. The polyols were tentatively identified as inositol and xylitol.
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