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Showing 1 to 20 of 33 for “"DMTA"”.
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Secondary interactions in blends of lignin and cellulose derivatives: composite morphology and properties
… (DSC) and dynamic mechanical thermal 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 …
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Damage accumulation in hybrid woven fabric composites.
… volume fraction in the non-hybrid composites. DMTA tests were carried out on the laminates of the categories mentioned above, the test results indicated the effect of fibre surface treatment concentration on the performance of mechanical properties of woven composites. DMTA data has been used …
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The Effect of Matrix Molecular Weight on the Dispersion of Nanoclay in Unmodified High Density Polyethylene
… testing, dynamic mechanical thermal analysis (DMTA), as well as dynamic and capillary rheometry were performed on the nanocomposites. Nanocomposites generated from the high molecular weight (HMW) HDPE matrix exhibited increased intercalation of the MMT as shown by XRD as well as greater …
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Aspects of amidization of chitosan
… study several characterization methods including DMTA, TMA, TGA, X-ray diffraction, FTIR, solid state CP-MAS ¹³C NMR, and HPLC were used to study the transformation of various ionic complexes of chitosan (N-acylate) to their respective N-acyl homologs of chitosan; and several properties of these …
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Benign Processing of High Performance Polymeric Foams of Poly(arylene ether sulfone)
… cell walls. Dynamic mechanical thermal analysis (DMTA), on saturated CNF-PAES, was used to determine the reduced Tg due to plasticization and establish the temperature for pressure release during foaming. DMTA proved to be more effective than DSC in establishing quantitative results on the …
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Actuation of shape memory polymer using magnetic fields for applications in medical devices
… particles. Dynamic Mechanical Thermal Analysis (DMTA), tensile strain recovery tests, and Differential Scanning Calorimetry (DSC) were used to measure the mechanical effects of various particle volume contents and sizes on shape memory polymer. These tests suggest that the proposed method of …
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Multiphase star-like copolymers containing lignin: synthesis, properties and applications
… of these copolymers were investigated by DSC, DMTA and optical microscopy. The copolymers exhibited variable thermal behavior in relation to composition. The crystallization of PCL blocks was mainly governed by the nature of the HPL phase. PCL block length was another variable that affected …
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Manufacture and rehabilitation of guard-rail posts using composites for superior performance
… properties was measured using flexure tests and DMTA. The performance in terms of modulus and rigidity was reduced the most by acidic medium, and the least by saltwater medium. It was concluded that under unaged conditions, the flexural rigidity of wood is improved by 162% due to composite …
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Synthesis and characterization of novel bismaleimides derived from arylene phosphine oxides and ether-ketones
… exhibited glass temperatures around 380-400°C by DMTA and TMA. The phosphine oxide bismaleimides demonstrated an exothermic curing peaks >180°C, suggesting that a practical processing range exists. Qualitatively the networks show excellent flame resistance compared to commercial controls. In …
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Effect of manufacturing process conditions on the durability of pultruded vinyl ester/glass composites
… cycling had no effect on the strength. DMTA analysis showed that an increase in glass transition temperature, Tg, occurred with increased aging temperature, indicating additional cross-linking had occurred. However, results showed that line speed in the range examined did not affect …
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Mechanics of amorphous polymers and polymer nanocomposites during high rate deformation
… included dynamic mechanical thermal analysis (DMTA), as well as uniaxial compression tests over a wide range of strain rates. In both cases, the polymer exhibited a distinct transition in the rate-dependent yield behavior, under the same temperature/strain rate conditions as the observed …
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Durability of fiber-reinforced composite wrap system for the rehabilitation of concrete structures
… of Dynamic Mechanical Thermal Analysis (DMTA) and Tension tests conducted on separate composite coupons that were aged in a similar environment as the cylinders. (Abstract shortened by UMI.).
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Fabrication and Gas Permeation Studies on Polyimide/Layered-Aluminum Phosphate Nanocomposite Membranes
… nanocomposite structure. Transmission FTIR, TEM, DMTA, and X-ray diffraction were used to characterize the morphology, structure, and composition of these nanocomposite films. The permeation properties of the nanocomposite membranes were evaluated using pure gases (He, O₂, N₂, CH₄, CO₂) at 35°C …
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UV curable powder coatings for the finishing of leather
… have been studied by DSC, SEM, FTIR-ATR and DMTA methods. It was found that the polyurethane acrylate binders (made from DHBA, BEP, DEG and HDI etc.) are potentially useful for formulating novel powder coatings. The properties of the developed powder coating finished leather have been tested. …
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Influência do tipo e teor de comonômero na estrutura e propriedades de copolímeros de etileno sintetizados com catalisador metalocênico
… DSC, WAXS, espectroscopia Raman de modo interno, DMTA, ensaios de tensão/deformação, etc. Em geral, foi observado um decréscimo na cristalinidade e temperatura de fusão dos copolímeros com o aumento do teor de comonômero incorporado nos mesmos, independente do tipo de ramificação. Quando …
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Estudo do comportamento cinético e mecânico-dinâmico de resinas epóxi a base de óleo de soja epoxidado
… por análise térmica dinâmico-mecânica (DMTA) e termogravimétrica (TGA). Todas as amostras apresentaram características de materiais termofixos. Os materiais termofixos obtidos a partir de anidridos com estruturas rígidas (FTA, MAL e CH) mostraram alta temperatura de transição vítrea e …
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Star-like macromers from lignin
… oxide units per arm. Thermal analysis by DMTA of lignin derivative-containing blends with ethylene-vinyl acetate copolymer indicated that the glass transition behavior of the star-like macromers follows the Gordon-Taylor relationship for copolymers. Although variable, the results revealed …
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Lignin acrylate derivatives and their behaviors in free radical copolymerizations
… (DSC), dynamic mechanical thermal analysis (DMTA), and by scanning electron microscopy (SEM). The influences of vinyl content in lignin acrylate derivatives and the ratio of lignin derivatives to vinyl monomer or macromer were studied with respect to structure-property relationship in the …
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Cure studies of network-forming polyurethanes
… studied via dynamic mechanical thermal analysis (DMTA). HPC/MDI and HPL/MDI resins flow at 30°C and proceed to cure at 50°C. The latter has excellent thermal stability over the former. Crosslinking of HPL and HPC with MDI follow an nth order kinetics, with an order of reaction of 2 and an apparent …
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Synthesis and characterization of high Tg nanofoams based on pyromellitic dianhydride and 1,1-bis(4-aminophenyl)-1-phenyl-2,2,2-trifluoroethane polyimide block and graft copolymers
… imidization. Dynamic mechanical analysis (DMTA) confirmed microphase separated morphology for all the copolymers. Upon degradation of poly(propylene oxide), a 13-18% reduction in the density was observed, which is consistent with foam generation. These features have been confirmed using …
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