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 38 for “"Polyurethane (PU)"”.
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Structural characterization of polyurethane foam and implications of aging
Polyurethane (PU) foam is used as a shock mitigation material in the national stockpile, which degrades over time. A replacement foam, ReCrete was shown to exhibit acceptable mechanical properties after aging, but fractured with impact testing. Previously, processing ReCrete foam at elevated …
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Polymerized ionic liquids by condensation polymerization: Stimuli responsive polyurethane gels and dispersions
… explores incorporation of ionic liquids in polyurethane (PU) polymers to make PIL PU gels and dispersions through condensation polymerization. PIL gels are synthesized through a single-pot approach that show stimuli response to solvents. This approach allows one to make these gels rapidly …
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Desenvolvimento de membranas de matriz mista para separação de O2/N2
The production of enriched and/or purified O2 is closely linked to energy and environmental aspects. So, one of technology alternatives to reduce O2 production cost are membranes for gas separation. But, to compete with conventional separation technologies, the development of new materials have …
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Heparanoid hydrogels for cardiovascular tissue regeneration
… evaluated in vivo as ingrowth matrices in porous polyurethane (PU) scaffolds for healing response in a rat subcutaneous model.
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Surface Modification of Commonly used Polymer Plastics for Increased Hemocompatibility in Medical Equipment
… (PP), poly (methyl methacrylate) (PMMA), polyurethane (PU), polysulfone (PS). All materials had MEG-OH adlayer formed and characterized with x-ray photoelectron spectroscopy, attenuated total internal reflection and contact angle goniometry. Several of the materials (PVC, PC, and PS) were …
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Chronic Ocular Hypertensive Model using Microbead Injection in Rats: Comparison of Polyurethane, Polymethylmethacrylate, and Polystyrene
Purpose: To establish and assess an ocular hypertensive rat model using intracameral injection with various microbeads of different sizes and materials. Methods: Chronic elevation of intraocular pressure (IOP) was induced by injection of various microbeads into the anterior chamber of …
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Investigating Differences in Douglas-fir and Southern Yellow Pine Bonding Properties
… with two adhesives, a one-part moisture cure polyurethane (PU), and a two-part ambient curing phenol-resorcinol-formaldehyde (PRF). Shear stress for southern yellow pine was affected the most by the type of growth regions at the bond (juvenile to mature wood) and the assembly times of the …
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Effects of Therapeutic Radiation on Polymeric Scaffolds
… three porous scaffolds: polycaprolactone (PCL), polyurethane (PU) and gelatin. Porous scaffolds were fabricated using solvent casting and/or salt leaching techniques. Scaffolds were placed in phosphate buffered saline (PBS) and exposed to a typical cancer radiotherapy schedule. A total dose of 50 …
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The performance of polyurethane grout to stabilise hemic peat
… years for sustainable construction on peat. The polyurethane (PU) grouting as an option is similar to the cement base grouting application widely used for ground improvement. However, the PU grouting is a strong lightweight material with very short curing time. The Parit Nipah hemic peat has high …
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Effect of composition and sintering temperature on silica-nickel oxide foams by slurry method
… to prepare slurry solution for impregnation of polyurethane (PU) sponge as the template. Silica-Nickel Oxide foams were fabricated by slurry method and sintered at 1000ºC, 1100ºC, 1200ºC and 1300ºC. Characterisation of SiO2-NiO foams included morphological analysis, porosity and density test, …
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Acoustical characteristics of oil palm mesocarp fibres
… as fibrous acoustic material. Incorporated polyurethane (PU) had improved the sound absorption coefficient (SAC), especially at low frequency range. The oil palm Mesocarp fibres were mixed with four different percentages of PU, namely 10%, 20%, 30% and 40%. The measurement of SAC was done …
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Fabrication and characterisation of Cobalt Chromium Molybdenum (CoCrMo) foams using slurry method
… for another 1 hour until it becomes slurries. Polyurethane (PU) foam is then impregnated into the slurry and dried at 40°C for a day in the oven. It was found that the possible composition were 60wt%, 65wt% and 70wt% for CoCrMo. This was followed by the appropriate sintering temperature results …
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Development and applications of acid degradable polymeric materials
… section discusses a new mechanism for degrading polyurethanes called CyclizAtion-Triggered Chain (CATCH) cleavage. CATCH cleavage features a simple glycerol-based acyclic acetal unit as a kinetic and thermodynamic trap for chain shattering. Thus, transient oxocarbenium ion formation with an …
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Predicting the thermal performance of bio-based cold chain packaging system
… This research combines experimental and computational approaches to improve the thermal efficiency and environmental sustainability of passive cold chain packaging systems. The first phase of the study (Chapter 1) focuses on predicting the thermal performance of bio-based ISCs through finite …
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Characterization of graphite polyurethanes composite from renewable based oils
… to evaluate the characterization of graphite polyurethane composite from renewable based oils. Virgin cooking oil (VCO) as a renewable resource is the main substance in fabricating the renewable polyurethane (PU) and its graphite as called polyurethane graphite (PG). The fabricating sample …
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Physical and acoustic properties of petroleum and renewable based polyurethane foam filled with shorea leprosula
… and acoustic properties of petroleum-based polyurethane (PU) and renewable based polyurethane (RPU) foam composites filled with Shorea Leprosula (Red Meranti) fiber filler has been investigated. Shorea Leprosula wood dust namely as SL was used as the filler. RPU was used with hope to …
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Polyurethane foam from oil palm fruit waste: synthesis and characterization of biopolyol and foam properties
… The aim of this research is to produce of polyurethane (PU) foams with biopolyols from liquefied oil palm fruit waste (PW). Three parts of oil palm fruit waste (PW): oil palm mesocarp fiber (PM), oil palm shell (PS) and oil palm kernel (PK) was liquefied using liquefaction solvent with …
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Synthesis and applications of ceramic (silicon carbide and silicon nitride), metallic (cobalt(0)) and polymeric (polyurethane) aerogels
… for the synthesis of monolithic ceramic and purely metallic aerogels from xerogel powder compacts, and the use of polyurethane aerogels based on cyclodextrins as efficient desiccants.</p><p>I. Highly porous ( > 80%) monolithic SiC and Si<sub>3</sub>N<sub>4</sub>, aerogels were prepared from …
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Development of a tissue-regenerative vascular graft: Structural and Mechanical Aspects
… grafts, comprising ingrowth permissible porous polyurethane (PPU) foam and knitted reinforcement wire mesh, with the aim of providing vascular prostheses that mimic arterial mechanics. A 3D geometry of a knitted eight-loop wire mesh was imported into Abaqus CAE® 6.8-2 and assembled …
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Coating Performance on Preservative Treated Wood
… and film thickness. Also penetration depth of a polyurethane (PU) coating was examined using Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS). iii All the stains evaluated effectively reduced cumulative leaching of preservative components by about 60% on average. An analysis of the …
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