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 19 of 19 for “"Phase morphology"”.
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Phase morphology and fracture toughness of CNT/polytherimide modified epoxy polymer nanocomposites as matrices for advanced CFPR composites
… included carbon nanotubes (CNTs) and a phase separating thermoplastic (TP) material. Two types of epoxy resins were used and compared in this study, namely a high performance tetrafunctional epoxy and a standard bifunctional type. The resulting systems included various binary and ternary …
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Investigation of Phase Morphology and Blend Stability in Ionomeric Perfluorocyclobutane (PFCB)/Poly(vinylidene difluoride) (PVDF) Copolymer Blend Membranes
This research is focused on the investigation of phase morphology and blend stability within ionomeric perfluorocyclobutane (PFCB)/poly(vinylidene difluoride) (PVDF) copolymer blend membranes. The morphologies of these unique materials, designed as proton exchange membranes (PEMs) for proton …
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Multiscale In-Situ Characterization of Crystal Orientation, Temperature, and Microstructure Effects on Creep Defromation of Pure Magnesium and Mg-Al-RE Alloys
… how crystal orientation, temperature, and β-phase morphology govern creep behavior in pure Mg and AE44 alloys. Novel in-situ nanoindentation creep methods were developed using an indenter inside a SEM. Additional techniques included in-situ tensile creep testing, scanning electron microscopy …
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Polydimethylsiloxane Modification of Segmented Thermoplastic Polyurethanes and Polyureas
… The effect of PDMS content on thermal stability, morphology, surface composition, mechanical properties, and fire resistance of polyurethane was investigated. These polymers displayed a complex two phase morphology and composition-dependant mechanical properties. The PDMS segment microphase …
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Modeling the microstructure development in gray iron castings
… other microstructural features such as second phase morphology and distribution are the primary factors in determining the mechanical properties in cast metals. In this work, a representation of nucleation and growth kinetics for gray cast irons, based on a statistical description of the …
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Modification, curing and flame retardation of epoxy resin networks
… further confirmed the development of a two phase morphology in modified systems and that it could be controlled from a dispersed thermoplastic in a continuous epoxy phase, to a phase inverted morphology as the modifier increased from approximately 15 to 30 weight percent. Improvements in …
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Stress Effects on Phase Morphological and Compositional Non-uniformity in Intercalation Compounds
… from these compounds frequently induces phase transformations, and the resultant microstructure evolution plays an important role in the (de)intercalation kinetics, performance and reliability of the systems. In this thesis, theoretical analyses and mesoscale simulations are carried out …
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Bioinspired mineralization in hydrogels for sustainable materials processing
… the matrix as nano- and/or microparticles. The phase, morphology, and size of the particles can be controlled using the choice of the hydrogel, functional moieties on the gel polymer backbone or ends, and soluble additives. Depending on the choice of organic matrix and inorganic mineral, the …
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LEVERAGING CONFINEMENT AND SURFACE EFFECTS TO CONTROL POLYMER PHASE BEHAVIOR AND TRANSPORT PHENOMENA IN POLYMER-INFILTRATED NANOPARTICLE FILMS
… surface interactions may substantially alter phase behavior from bulk expectations. Additionally, the prevalence of adsorbed polymer layers within PINFs present an opportunity to engineer a polymeric material dominated by interfacial effects, with little or no bulk region. In this thesis, we …
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Designing Acrylic Block Copolymers with Multiple Hydrogen Bonding or Multiple Ionic Bonding
… which contributed to a well-defined ordered morphology and enhanced resistance to moisture uptake. A facile 2-step synthesis provided doubly-charged styrenic DABCO salt monomer(VBDC₁₈BrCl) containing an octadecyl tail. RAFT polymerization allowed the preparation of DABCO ABA block copolymers …
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Secondary interactions in blends of lignin and cellulose derivatives: composite morphology and properties
… analysis (DMTA) were used to characterize the morphology of solvent cast hydroxypropyl cellulose (HPC) films. These techniques revealed the existence of three phases in the bulk material: 1) an amorphous phase, 2) a crystalline phase, and 3) a phase of intermediate order which arises as a …
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Development and validation of a thermodynamic model for predicting mode transitions in falling film flows over horizontal tubes
… well as the need to start with some assumed two-phase morphology. On the other hand, an empirical approach is obviously limited to the experimental range of the fitting data. Hence, falling-film applications call for a mode prediction method, especially for new systems, which is applicable for a …
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Structure-property relationships of multiphase copolymers
… of the PBS backbone were analyzed. A two phase morphology was found to exist with PDMS domain size increasing with increasing PDMS graft length. The type of morphology observed was dependent on PDMS composition, and in some cases the degree of polymerization and average number of …
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Controlling Cocontinuous Polymer Blends with Nanofillers Jammed at the Interface
… melt compounding of immiscible polymers or phase separation of partially miscible polymer pairs via spinodal decomposition. The polymer blends with cocontinuous structure have significantly improved mechanical properties and they have applications in conductive plastics, porous membranes for …
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Microporous polymeric membranes via melt processing
… glass transition temperature (T_g) of the minor phase. Crazing structure is initiated during the post-step treatments. The dimensions of the crazes are then enlarged by a series of stretching processes that comprise consecutive steps of cold stretching followed by hot stretching. Rates of craze …
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Electrochemical and Transport processes in Ion Intercalation materials
… most ion intercalation materials tend to phase separate into ion–rich and –poor phases under ion insertion/extraction. Our understanding, however, on the effects of intercalation rates, applied electric fields and the microscopic nature of the reactions on the resulting phase morphologies …
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Silica-based nanocomposite membranes via the sol gel process of polyethoxysiloxane within a sulfonated poly(ether-ether-ketone) matrix: morphology and proton mobility
… obtained from solutions, where the organic phase is the sulfonated poly(ether ether ketone) (SPEEK) and the inorganic phase are silica nanoparticles obtained from the in situ "water free" sol-gel process of polyethoxysiloxane (PEOS). PEOS is a soluble and liquid hyperbranched polymer of low …
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GREEN CATALYTIC STRATEGIES FOR THE PRODUCTION OF BIOBASED BUILDING-BLOCKS
… a focus was given on the study of copper phase morphology, wettability and acidity of the surfaces. The first part of the Ph.D project was devoted to study the hydrogenation of γ- valerolactone (GVL) to 1,4-pentanediol (1,4-PDO) (scheme A1), using silica supported copper catalysts under …
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MULTI-IONIC LITHIUM SALTS FOR USE IN SOLID POLYMER ELECTROLYTES FOR LITHIUM BATTERIES
… aggregate and crystallize, forming a biphasic morphology, in which the phenyl rings form the structural phase and the POSS-PEG8 forms the conductive phase. The -Si-O-BF3- Li+ groups of POSS-phenyl7(BF3Li)3 are oriented towards the polar POSS-PEG8 phase and dissociate so that the Li+ cations are …