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Showing 1 to 20 of 347 for “"Glass Transition temperature"”.
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The Effects of Electron Radiation on the Glass Transition Temperature of a Polyetherimide
… investigated. In particular, the changes in the glass transition temperature (T<sub>g</sub>) with absorbed radiation dose were studied. The polymer was exposed to mono-energetic beams of 100-keV electrons and 1.0-MeV electrons for doses up to 100 megagray (MGy). Dosimetry for the exposures was …
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Effect of heat treatment on dyeability, glass transition temperature, and tensile properties of polyacrylonitrile fibers (orlon 42)
… after they were boiled in water for 15 min. The glass transition temperatures (Tg) were obtained by differential scanning calorimetry. The ratio of the intensities of the CN/CH stretching bands were found by infrared spectroscopy, using the KBr method
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Roles of mesh size, segmental dynamic, glass transition temperature and molecular structure on penetrant diffusion in dense vitrimers
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2026-05-01
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Temperature and rate dependent finite strain behavior of poly(ethylene terephthalate) and poly(ethylene terephthalate)-glycol above the glass transition temperature
… process and the stress-strain behavior above the glass transition depend strongly on temperature, strain rate, strain magnitude, and strain state. A robust constitutive model to accurately account for this stress-strain behavior in the processing regime is highly desirable in order to predict and …
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A constitutive theory for the mechanical response of amorphous metals at high temperatures spanning the glass transition temperature : application to microscale thermoplastic forming of Zr₄₁.₂Ti₁₃.₈Cu₁₂.₅Ni₁₀Be₂₂.₅
Bulk metallic glasses (BMGs) are a promising emerging engineering material distinguished by their unique mechanical properties and amorphous microstructure. In recent years, an extremely promising microscale processing method for bulk metallic glasses, called thermoplasticforming has emerged. As …
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Crosslinked conventional size and nanoparticle size acrylic latexes and their blends: Investigation of the effects of crosslinking, particle size and distribution, glass transition temperature and blending on film formation, properties and morphology
… particle size ~ 120-130 nm) and distribution, glass transition temperature (Tg), and blending on latex film formation process, properties and latex morphology. Films cast from these latexes were characterized using specific end use tests and fundamental properties using advanced instruments …
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Solid-state Polymer Nanofoams
… (or equivalently molecular weight) and varying glass transition temperature. Molecular weight and glass transition temperature are two of the most important parameters of polymers; however, their effect on cell nucleation was not reported previously in literature. In this study, it is found that …
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Effect of chemical structure and crosslinking density on the thermo-mechanical properties and toughness of (meth)acrylate shape-memory polymer networks
… network chemical structure, crosslink density, glass transition temperature, rubbery modulus, failure strain, and toughness. The glass transition temperature of the networks ranged from -29 to 112 °C, and the rubbery modulus ranged from 2.8 to 129.5 MPa. At low crosslink density (Er < 10 MPa) …
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Mechanistic Insights into the Stabilisation of Biopharmaceuticals using Glycine Derivatives. The Effect of Glycine Derivatives on the Crystallisation, Physical Properties and Behaviour of Commonly used Excipients to Stabilise Antigens, Adjuvants and Proteins in the Solid State
… the crystallisation and increase the overall glass transition temperature, of mannitol, when freeze dried as evidenced by DSC and Powder X-ray diffraction. Mannitol’s glass transition temperature increased from 100C to 12.650C and 13.610C when mixed with methyl-glycine and dimethyl glycine …
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A thermo-mechanical finite deformation theory of plasticity for amorphous polymers : application to micro-hot-embossing of poly(methyl methacrylate)
… materials; however, their nonlinear, strongly temperature- and rate-dependent elastic-visco-plastic behavior has, until now, not been very well understood. The behavior has previously been modeled with mixed success by existing constitutive theories. As a result, there is currently no generally …
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Altering an Epoxy-Amine Thermoset's Performance Through Varying Mix Ratios
… mix ratio (Part A : Part B), cure time, and cure temperature, for example. Due to proprietary reasons, it can be difficult to understand why these values are provided, and more importantly, the consequences when deviating from the prescribed recommendations. When manufacturing bioprocessing …
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Effect of carbon nanoparticle addition on epoxy cure
… thesis reports studies of cure kinetics and the glass transition temperature advancements of three commercial epoxy resin systems: MY 750 / HY 5922 (Vantico), MTM 44 -1 (ACG) and 8552 (Hexcel Composites). This investigation was conducted with the utilisation of Differential Scanning Calorimetry …
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A large-deformation thermo-mechanically coupled elastic-viscoplastic theory for amorphous polymers : modeling of micro-scale forming and the shape memory phenomenon
… materials; however, their nonlinear, strongly temperature- and rate-dependent elastic-viscoplastic behavior is still not very well understood, and is modeled by existing constitutive theories with varying degrees of success. There is no generally agreed upon theory to model the …
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Uranium Enrichment Signatures of Fluorinated Epoxy
… uranium can cause a detectable change in the glass transition temperature in UV cured fluorinated epoxy (a material which can be used uranium enrichment cascades) at doses equivalent to enriching enough uranium to make on the order of 1 significant quantity (IAEA standard). This change in the …
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Characterization of polystyrene-block-poly (acrylic acid) micelles
… of PAA homopolymer. Annealing near or below the glass transition temperature for 16 hours increased the order of the films, as was demonstrated by Fast Fourier Transforms of their AFM images. Annealing for longer periods of time or at temperatures significantly above the glass transition …
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The Effects of Structure, Humidity and Aging on the Mechanical Properties of Polymeric Ionomers for Fuel Cell Applications
… increase in the degree of sulfonation raised the glass transition temperature of these materials by facilitating the formation of the ionic clusters which acted as physical crosslinks, thereby reducing the mobility of polymeric chains. Water was found to effectively plasticize the membranes, …
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Structure-property relationships of electron beam cured systems containing bis-GMA
… called bis-GMA, is a viscous liquid at room temperature which crosslinks to form a glassy network when a 3 to 5 mil coating is irradiated with sufficient energy. The major parameters which were systematically varied in this study were radiation dosage, dose rate, aging time after irradiation, …
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Low Temperature Behavior of Potassium and Sodium-Silicate Glasses
The low-temperature properties of a system of well characterized potassium and sodium silicate glasses have been measured in an effort to better understand the nature of the low-energy excitations which exist in all glasses and to further investigate relationships between the low-temperature …
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Atomistic simulations of elastic-plastic deformation of amorphous polymers
… origins of plastic deformation of an amorphous glassy polymer were studied using atomistic simulations. Understanding of the molecular response will aid the development of physics-based continuum level models for these materials. A polyethylene-like molecular network was numerically constructed …
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Studies on the hydro-thermal and viscoelastic properties of leather
The temperature dependent viscoelastic behaviour of synthetic polymers has been shown to be of high importance for their properties and applications. However for leather this aspect of viscoelasticity has not been studied. In order to further the understanding of structure-property relationships, …
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