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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 168 for “"Dynamic mechanical analysis"”.
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Dynamic mechanical analysis of magnetic tapes at ultra-low frequencies
… tapes, using a custom, ultra-low frequency, dynamic mechanical analyzer. The long-term mechanical and thermal properties of magnetic tapes can be simulated using high temperature and low frequency dynamic mechanical analysis (DMA) experiments. These experiments investigate how the …
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Dynamic mechanical analysis of graphite/epoxy composites with varied interphases
Dynamic mechanical analysis (DMA) has been used extensively to characterize polymeric materials. This thesis investigates the use of this technique to characterize composite materials. Four material systems, all having the same fiber and the same matrix material, were systematically altered with …
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The Isolation of Cellulose Nanocrystals from Pistachio Shells and Their Use in Water Actuating Smart Composites
… (TPU) to observe the reinforcement effects by dynamic mechanical analysis. Pistachio shells offered a high yield source material for CNCs, with a high aspect ratio but a low crystallinity. They did offer significant reinforcement of the TPU, but less than the commercially available wood-based …
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Influence of the Interphase on the Mechanical Properties of Nylon 66 Composites
The mechanical properties of glass fiber and carbon fiber reinforced nylon 66 were investigated using both microscopic and macroscopic testing techniques. The objective was to determine how different interphase morphologies affect the adhesion and properties such as damping, ultimate stress and …
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Application of Thermomechanical Characterization Techniques to Bismuth Telluride Based Thermoelectric Materials
… little has been published on the thermomechanical properties. In this paper, dynamic mechanical analysis (DMA) and differential scanning calorimetry data for bismuth telluride based TE materials is presented. The TE materials' tan delta values, indicative of viscoelastic energy …
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Damorheology: creep-fatigue interaction in composite materials
… at the lamina level is represented by the dynamic stiffness, residual strength and fatigue life of unidirectional laminates. The time dependent behavior is represented at the lamina level by a Pseudo-Analog Mechanical model. The thermo-rheological characterization procedure combines …
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Time, temperature and frequency viscoelastic behavior of commercial polymers
… time, t, from the master curve obtained by TTSP. Dynamic Mechanical Analysis (DMA) tests were done to get complex relaxation modulus, E*(o), as a function of frequency. Frequency Temperature Superposition (FTSP) was done to extend the frequency range. Mathematical transformations from the …
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Structure-property behavior of sol-gel derived hybrid materials
… and structural information gained from dynamic mechanical analysis, small angle x-ray scattering and scanning electron microscopy. The incorporation of titanium was found to increase the measured Young’s modulus and stress at break relative to comparable materials based solely on TEOS.
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Functional Block Copolymers via Anionic Polymerization for Electroactive Membranes
… This provides conductive materials with robust mechanical stability, efficient processability, and tunable macromolecular design. Conventional free radical polymerization and anion exchange achieved copolymers containing n-butyl acrylate and phosphonium ionic liquids. These compositions …
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Study of the miscibility, crystallization and morphology in poly(propylene) based blends and copolymers
… differential scanning calorimetry and dynamic mechanical analysis. These studies reveal that for the molecular weights investigated, it-PP and it-P1B form blends that are partially miscible in the liquid state. Liquid-liquid demixing is observed by optical microscopy at temperatures …
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Effects of Functionality and Charge in the Design of Acrylic Polymers
… tailor polymer properties using this technique. Analysis with MALDI-TOF/TOF spectroscopy revealed the dominance of a back-biting side reaction at elevated temperatures. Hydroxy-functional random and block copolymers of n-butyl acrylate (nBA) and 2-hydroxyethyl acrylate were synthesized using …
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Novel Rubber Nanocomposites with Adaptable Mechanical Properties
… this specific interaction further enhances the mechanical properties of these nanocomposites. In order to attach hydrogen bonding interacting moieties, the rubbers used in this study were chemically modified via several pathways. Instead of carbon black and conventional silica particles, the …
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Understanding Ferroelastic Domain Reorientation as a Damping Mechanism in Ferroelectric Reinforced Metal Matrix Composites
… have limited inherent ability to dampen mechanical or acoustic vibrations. The addition of ferroelectric ceramic particles may also augment the strength of the matrix, creating a multifunctional composite. The damping behavior of two FR-MMC systems has been examined. One involved the …
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Characterization of photocurable networks in real-time and post-exposure
… behavior in real-time and post-exposure. In situ dynamic mechanical analysis was performed to observe the changes in composite modulus during photopolymerization of thin acrylate films supported on stainless steel grid sheets. Vitrification phase transformations were monitored in real-time via …
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Kinematics of Inter-Ply Interfaces In Composite Manufacturing
… cycle design, interface modification, and thermomechanical modeling for developing a fundamental understanding of the cure kinetics during composite manufacturing. Strains, ply-movement, and formation of defects are observed in-situ using digital image correlation (DIC) during the autoclave cure …
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A reactive melt modification of polyethylene terephthalate
… carboxyl content, insoluble content, and by dynamic mechanical analysis. The importance of undesirable melt degradation reactions occurring simultaneously with the branching/extension reactions is analyzed. Valuable information is obtained from the designed batch mixer experiments regarding …
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Thermal and Morphological Study of Segmented Multiblock Copolyesters Containing 2,2,4,4-Tetramethyl-1,3-cyclobutanediol
… scattering, wide angle X-ray diffraction and dynamic mechanical analysis. Molecular origins of the thermal transitions appearing in copolyesters were assigned by the copolyester analysis at different temperatures. The hard segments in copolyesters underwent short-range and long-range ordering …
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Carboxymethylcellulose Acetate Butyrate Water-Dispersions as Renewable Wood Adhesives
… viscometry, differential scanning calorimetry, dynamic mechanical analysis, light and fluorescence microscopy, and mode I fracture testing. Thermal analyses showed that the polymer glass transition temperature significantly increased when bonded to wood. CMCAB dispersions produced fairly brittle …
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