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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 29 for “"Cyanate"”.
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The Marine Cyanate Cycle
<p>Cyanate (OCN-) is a reduced nitrogen compound with the potential to serve as a nitrogen and carbon source for marine microbes. Evidence from genomes and culture studies indicated that several marine cyanobacterial groups, including representatives of the globally important genera Synechococcus …
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NMR investigations of cyanate resins
… polymers with a particular focus on cyanate resin polymer systems, which are newly-developed thermo set resins used for electronic circuit boards and many structural composites. The mechanism of the curing reactions of cyanate resins based on bisphenol-A dicyanate has been …
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Processing of toughened cyanate ester matrix composites
… the feasibility of recently developed toughened cyanate ester networks as candidate materials for high performance composite matrix applications. The resin investigated was a Bisphenol-A cyanate ester toughened with hydroxy functionalized phenolphthalein based amorphous poly(arylene ether …
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Toughening of cyanate ester networks with reactive thermoplastic modifiers
Cyanate ester or triazine networks are attaining increasing importance as potential candidates for high temperature adhesives and composite matrices. Low toughness is a major drawback with most crosslinked thermosetting materials, including the cyanate ester networks. Considerable attention has …
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Synthesis and characterization of heterocyclic polymers: polybenzoxazoles and cyanate ester networks
… The second portion of the thesis focused on cyanate ester or polycyanurate networks generated from dicyanate monomers. The influence of electron withdrawing and donating groups on the behavior of the network forming curing process was investigated. It was demonstrated that electron …
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Cyanate Formation Following 2-Chloroacrylonitrile Exposure and the Role of Cytochrome P-450
… Cardiac blood was collected for cyanide and cyanate analysis. Liver and lung tissues were harvested and analyzed for glutathione. In a separate experiment, the time to onset of hind limb paralysis was measured in animals receiving 40 mg/kg 2-CAN and 100 mg/kg 5P1P one hour prior to 40 mg/kg …
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High-Temperature Performance of Carbon Fiber Reinforced Cyanate Ester Composites Filled with Nano-Ceramics
… carbon fabric reinforced nano-ceramics modified cyanate ester composite material is fabricated for the field of high temperature applications. The effect of using nano-ceramics as a filler element in the cyanate ester resin will be evaluated. High temperature materials play a vital role in the …
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Analysis of Cyanate Ester Resins and Graphite Fabric for Use in Resin Film Infusion Processing
… of this investigation was to characterize two cyanate ester resins and a eight harness satin (8HS) graphite fabric for use in resin film infusion (RFI) processing. Two cyanate ester resin systems were characterized to determine their cure-kinetics, and viscosities during cure. A 8HS graphite …
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Development of Bismaleimide/Cyanate Ester Based Aerospace Polymers for Possible Use in NASA's Relaunchable Vehicles Program
… polymer. Because of this gap, bismaleimides and cyanate esters, and possibly combinations of the two, are seen as having potential in applications where ease of processing characteristic of epoxies is desired, but for which temperature resilience better than that of epoxies is desired. In this …
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Electrophilic C(sp²)–H Cyanation with Inorganic Cyanate (OCN⁻) by Pᴵᴵᴵ/Pⱽ=O-Catalyzed Phase Transfer Activation
… cyanation of C(sp²)–H nucleophiles with sodium cyanate (NaOCN) is reported. Mechanistic experiments show that under solid-liquid phase transfer, an inorganic cyanate is activated by halide displacement on a halophosphonium. Redox catalysis is enabled by the usage of a strained phosphine …
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Examination of the Aging Properties of Novel Cyanate Ester Thermosets and the Subsequent Evaluation of the Material under Application Conditions
Cyanate ester thermosetting resins are a novel family of materials for high technology and aerospace applications. The high glass transition temperatures available from cured cyanate ester networks and subsequently, their resistances to corrosive materials make these resins attractive for harsh …
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Production of Functionally Gradient Materials Using Model Thermosetting Systems Cured in a Thermal Gradient
… following cure in the gradient temperature mold. Cyanate ester materials were modified with hydroxyl-terminated butadiene-acrylonitrile copolymers as well as low Tg amorphous polyesters. The polyesters showed very desirable properties for a toughener, including relatively good thermo-oxidative …
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Modelling of the degradation of mechanical properties of glass fiber reinforced composites (GFRP) due to environmental aging
… plenum is constructed, namely glass reinforced cyanate ester composite. Based on an extensive experimental work for the study of the hydrothermal ageing of glass reinforced cyanate ester composite at different temperature, the collected data was used for the development of an application, …
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The effects of process parameters on the properties of resin transfer molded composites
… plain weave fabrics. Vinyl ester, epoxy, and cyanate ester resins were pressure injected into these fabrics. The epoxy panels were processed with varying injection temperatures and pressures. A density-based technique was used to measure the fiber volume fraction and void content of the …
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Development of new catalytic transformations and reagents for the construction of C-N and C-S bonds
… of Aryl Chlorides and Triflates with Sodium Cyanate: A Practical Synthesis of Unsymmetrical Ureas. An efficient method for palladium-catalyzed cross-coupling of aryl chlorides and triflates with sodium cyanate is reported. The protocol allows for the synthesis of unsymmetrical N,N'-di- and …
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Approaches Towards a Total Synthesis of Daphenylline
… available (S)-carvone through [3,3]-allyl cyanate-to-isocyanate rearrangement, intramolecular Heck Reaction, and Intermolecular Diels-Alder/benzannulation strategies. Efforts towards the synthesis of daphenylline’s D ring are discussed. A terse introduction to the scientific literature of …
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Chemoenzymatic Formal Total Syntheses of Tetrodotoxin and an Approach to Daphenylline
… route employed a highly stereoselective allyl cyanate-to-isocyanate rearrangement to install the nitrogen atom at C8a. This protocol was also successfully applied in designing a synthetic avenue to daphenylline. The ABC tricyclic skeleton of daphenylline was successfully constructed in just …
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Production of controlled networks and morphologies in toughened thermosetting resins using real-time, in-situ cure monitoring
… was developed and the cure of a model toughened cyanate as well as a commercial paste adhesive was followed with this sensor In the near-infrared. The design was suitable for many applications. A mold was designed to incorporate the fiber sensor for composite applications. The growth of the …
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Diazine-bridged coordination polymers of copper and nickel : synthesis and thermal, spectral, structural, and magnetic properties
… abilities were employed. These include cyanate, nitrate, methanesulfonate, hexafluoroarsenate, hexafluorophosphate, chloride and thiocyanate anions. Polymeric and mononuclear compounds were isolated. The polymeric materials were found to be of three basic structural types: …
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