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Showing 1 to 20 of 72 for “"degree of crystallinity"”.
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The influence of degree of crystallinity on the thermal conductivity of nylon 66
The use of massive nylon as a material for bearing liners is limited by its low melting point ( 260 °C) and its low thermal conductivity (0.172 Btu per hour - square foot - °F per foot). This combination of defects results in the formation of hot spots at points of stress., and since the material …
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Effect of heat treatment on tensile properties, dyeability and crystallinity of nylon and polyester filament yarns
… column technique, was used to calculate the degree of crystallinity as a structural parameter. Filament tensile strength and elongation at break were measured on a constant-rate-of-extension machine, and then toughness of the sample was obtained from the load elongation curve. The amount of …
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Thermal anisotropy and conductivity studies of nylon 66
… nylon lends itself to many applications because of its outstanding toughness, abrasion-resistance, and chemical resistance. These properties make it a satisfactory bearing material, and in some applications it is superior to metallic bearings. However, the disadvantages of low melting point and …
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Effects of high pressure solidification on the tensile properties of polypropylene
… solidification should strongly influence the crystallinity, and hence mechanical properties, of those regular polymers which can crystallize when cooled from the melt. In this study, samples of isotactic polypropylene were solidified under pressures up to 40,000 psi. In addition to tensile …
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Characterisation of freeze dried amino acids and gelatin based rapidly Disintegrating tablets
Recent research has shown the feasibility of using individual or a combination of amino acids as a replacement component for sugars in RDT formulations. What has emerged from this work is the notion of an optimal concentration of amino acid, i.e. one that is sufficiently high to provide the desired …
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A numerical and experimental investigation of the effects of thermal history on the structure/property relationship of PPS/carbon fiber composites
The purpose of this investigation was to examine the effects of thermal history during cooling from the melt on the degree of crystallinity, morphology, and mechanical properties of (polyphenylenesulfide) PPS/carbon fiber composites. Three thermal treatments were employed in this study: isothermal …
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ΜΕΛΕΤΗ ΠΡΟΚΑΤΕΡΓΑΣΙΩΝ ΓΙΑ ΤΗ ΒΕΛΤΙΩΣΗ ΤΗΣ ΟΞΙΝΗΣ ΥΔΡΟΛΥΣΗΣ ΚΥΤΤΑΡΙΝΟΥΧΩΝ ΥΛΙΚΩΝ
IN THE PRESENT THESIS A STUDY OF THE ACID HYDROLYSIS OF PRETREATED AS WELL AS NOT PRETREATED CELLULOSIC MATERIALS TOOK PLACE, WITH DEVELOPMENT AND PROOF OF A NEW MODEL OF ACID HYDROLYSIS AND THE USE OF IT FOR THE EVALUATION OF PHYSICAL AND CHEMICAL PRETREATMENTS FOR THE IMPROVEMENT OF AND …
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The Irradiation Tolerance of Zirconium-based MAX Phases
Recent developments in the synthesis of MAX phases have successfully introduced phases incorporating zirconium. These materials have been nominated for applications that experience high temperatures and irradiation damage. In this work, two newly synthesised zirconium-based MAX phases were …
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Characterization of the crystallinity and mechanical properties of CTFE & CTFE copolymeric films as a function of cooling rate and the implications on adhesion
… an important processing variable, affecting the crystallinity of the CTFE films which in turn affect many properties including dielectric characteristics and mechanical properties. In this study, the crystallinity of CTFE and CTFE copolymeric films as a function of cooling rate was characterized …
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On-Line Consolidation of Thermoplastic Composites
… effect on the mechanical and physical properties of composite cylinders fabricated by on-line consolidation. A central composite experimental design was used to select the processing conditions for manufacturing the composite cylinders. The thickness, density, void content, degree of crystallinity …
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Crystallization and Melting Behavior of Linear Polyethylene and Ethylene/Styrene Copolymers and Chain Length Dependence of Spherulitic Growth Rate for Poly(Ethylene Oxide) Fractions
The crystallization and melting behavior of linear polyethylene and of a series of random ethylene/styrene copolymers was investigated using a combination of classical and temperature modulated differential scanning calorimetry. In the case of linear polyethylene and low styrene content copolymers, …
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Structure-property relationships in poly-(propylene-ethylene) copolymers
… microstructural and the mechanical properties of poly-(propylene-ethylene) bi-phasic copolymers. The copolymers investigated covered a comonomer content ranging between 4 and 23 percent ethylene. Nine grades were considered, with variables such as the melt flow index, the degree of …
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Molecular order at polymer surfaces via X-ray photoelectron spectroscopy
… gradient information from the top 6 run of the surface. It is found that all materials investigated present some kind of preferential and reproducible ordering effect. The ordering ef feet can be present in different forms, such as preferential segregation of a crystalline block to the …
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Crystallization and structure-property investigations of semicrystalline poly(arylene ether) based polymers
… melting and morphological characteristics of selected high temperature poly(arylene ether) based polymers. The first part deals with the studies carried out on a series of biphenol and hydroquinone based novel poly(ether ether sulfide)s which were investigated with respect to their …
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Study of poly (l-lactic acid)/poly (d-lactic acid) stereocomplex as nucleating agent for poly (l- lactic acid) crystallization
… effect brought by the PLA stereocomplex, samples of PLLA blended with different content of PDLA are prepared by the solution casting method. With different cooling rates (5, 15, 25 C/min), DSC non-isothermal crystallization experiments are performed. The results suggest that in the presence of the …
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The rational design of drug crystals to facilitate particle size reduction. Investigation of crystallisation conditions and crystal properties to enable optimised particle processing and comminution.
Micronisation of active pharmaceutical ingredients (APIs) to achieve desirable quality attributes for formulation preparation and drug delivery remains a major challenge in the pharmaceutical sciences. It is therefore important that the relationships between crystal structure, the mechanical …
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Trapping of hydrogen in Hf-based high κ dielectric thin films for advanced CMOS applications.
… silicates are emerging as some of the most promising alternatives to SiO2/SiON gate dielectrics in complementary metal oxide semiconductor (CMOS) devices. Extensive efforts have been taken to understand the effects of hydrogen impurities in semiconductors and its behavior such as …
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The crystallisation of Poly (aryl ether etherketone) (PEEK) and its carbon fibre composites
… through fibre reinforcement. The properties of PEEK and its composites are sensitive to changes in the crystalline content and morphology, which are influenced by the processing conditions. As such it is of great importance to have a good understanding of the crystallisation process of PEEK …
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Hydrothermal Carbonisation of Novel Biomasses
Renewable sources of thermal and chemical energy are needed in order to satisfy the world’s ever growing energy needs while limiting the rise of global temperatures below 2 °C above pre-industrial levels. Plant biomass is a vast resource which if harnessed properly could help revolutionise the …
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