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Showing 1 to 20 of 164 for “"PVA"”.
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Numerical Modeling of Polyvinyl Alcohol (PVA) Swelling and Dissolution in Water
… dissolvable elastomer from Polyvinyl Alcohol (PVA) replacing current not dissolvable rubber based materials. With fast development of hydraulic-fracturing in past 15 years, the oil and gas industry is in great need of dissolvable materials to fabricate certain temporary downhole tools in …
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EXPERIMENTAL STUDIES OF THE MECHANICAL BEHAVIOR OF A PVA DUAL-CROSSLINK HYDROGEL
… aims to understand the mechanical behavior of a PVA dual-crosslink hydrogel using both experimental and theoretical tools, with more focus on the experimental aspects. This PVA hydrogel is crosslinked by both chemical (permanent) and physical (transient) crosslinks. The chemical crosslinks remain …
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Evaluation of immobilizing horseradish peroxidase and alcohol oxidase in PVA-AWP polymer
… poly (vinyl alcohol) azide-unit water pendant (PVA-AWP). The immobilized enzyme films were to be used in biosensing applications and their stability and activity were determined colorimetrically and electrochemically. Compared to other gel immobilization techniques, PVA hydrogels offer several …
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Elastic stiffening in PVA-Borax studied with experimental medium amplitude oscillatory shear
… hydrogels; specifically, Poly(vinyl) alcohol (PVA) crosslinked with Sodium tetraborate (Borax), or PVA-Borax. We use medium amplitude oscillatory shear (MAOS) as a tool to measure asymptotically nonlinear viscoelastic material functions across a range of compositions of PVA-Borax with storage …
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Study of Mechanical Properties of PVA Fiber-Reinforced Concrete With Raman Spectroscopic Analysis
<p>The brittleness of concrete has always been a safety and economic issue of great concern. The low tensile strength of concrete is the cause of its intrinsic brittle nature. This is critical considering the amount of concrete used for the construction of highways, buildings, and other facilities. …
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Evaluating the use of cross-linked PVA nanoparticles for gene and drug delivery
… shift assays demonstrated how cross-linked PVA nanoparticles successfully form complexes with plasmid DNA and are of a size and charge that should, theoretically, permit endocytosis by eukaryotic cells. However, during in vitro transfection studies no reporter (GFP) gene expression was …
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PVDF-graphene conductive composite membrane and PVA-graphene conductive composite membrane preparation and application
… fluoride (PVDF) and polyvinyl alcohol (PVA) were used together with graphene to create graphene based polymer composite conductive membrane. First, Boehm titration was used to determine the linkage of carboxyl groups on the surface of graphene sheet. Then pure PVDF membrane was …
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Use of poly vinyl alcohol (PVA) cryogelation for tissue engineering: composites, scaffold formation and cell encapsulation
PVA cryogelation is a physical hydrogel formation method, which yields cryogels with comparable mechanical properties to vascular tissue. However PVA cryogels are not suitable for cell attachment and proliferation alone. This can be overcome by the development of composite cryogels. Moreover, …
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Comparative study of Physicochemical properties of novel Chitosan-GANT and PVA-GANT Hydrogels for drug delivery applications
… investigation with a previously autoclaved PVA-GANT hydrogel was carried out to validate the preliminary characteristics using IR spectroscopy, to verify the presence of cross-link bonds and morphology of pore formation by SEM microscope. Texture of the hydrogel (hardness, springiness, …
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Characterization of PVA-Borax-fructose gel for the capture of radioactive wastes generated during nuclear decommissioning activities
With the long-term objective of using polymer gels for the capture of solid, liquid and gaseous waste generated from decommissioning works, characterization of gel properties as well as the properties of the individual constituents of polymer gels has been completed. Characteristics of constituents …
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An investigation on the effect of solution concentration, applied voltage and collection distance on electrospun fibres of PVA solutions
… collection distance using poly (vinyl alcohol) (PVA) solutions on the fibre diameter and morphology of electrospun nanofibres. PVA solutions of 4%, 6% and 8% of mass percentage were used. The diameter and morphology of nanofibres formed were analysed under the Environmental Scanning Environmental …
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Preparation and characterisation of poly (vinyl alcohol)/chitosan/silicon dioxide (PVA/CS/SiO2) beads for the chromium (VI) (Cr(VI) removal
… poly (vinyl alcohol)/chitosan/silicon dioxide (PVA/CS/SiO2) beads were prepared by dropwise method by crosslinking with sodium hydroxide and ethanol and further crosslinked with glutraldehyde for the purpose of Cr(VI) ion removal in aqueous solution under UV irradiation. All of the samples of …
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Hydrogen-bonded layer-by-layer assembly of poly(vinyl alcohol) and tannic acid
… tannic acid (TA) and poly(vinyl alcohol) (PVA) were assembled under different pH conditions, and film growth and dissolution behavior was assessed through profilometry. Optimal film growth was achieved at pH 4.0, which contrasted with uncontrollable assembly at lower pH and lack of growth …
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Polyvinyl alcohol size recovery and reuse via vacuum flash evaporation
Polyvinyl alcohol (PVA) desize effluent is a high COD contributor to towel manufacturing plant's Primary Oxygenation Treatment of Water operation, and being non-biodegradable, is a threat to the environment. When all-PVA/wax size is used in weaving, significant incentives exist to recover the …
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Composite hydrogel-nanofibre vessels for vascular graft applications
… the feasibility of preparing polyvinyl alcohol (PVA) based hydrogels with controllable mechanical property was investigated. Three PVA based hydrogels were prepared by blending PVA with chitosan, gelatin or starch and by treatment with freeze-thaw cycles and coagulation. The synergistic …
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Desarrollo de inmovilizados de naringinasa en criogeles de PVA-PEG y en membranas de ultrafiltración para la reducción del amargor en zumo de pomelo
Uno de los principales problemas en la comercialización de los zumos de pomelo es su elevado amargor, debido a la presencia del flavonoide naringina. Esta Tesis Doctoral se centra en el desarrollo de inmovilizados de la enzima naringinasa que sean activos y estables para la eliminación del amargor …
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Development of Novel hydrogels for protein drug delivery
… research is development of poly (vinyl alcohol) (PVA) aqueous solutions that cross-link in situ to form a hydrogel that functions as an embolic agent for delivery of macromolecular drugs. Methods: PVA (14 kDa, 83% hydrolysed), functionalised by 7 acrylamide groups per chain, was used to prepare …
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Biobased And Biodegradable Polymer Nanocomposites
… nanocomposites using BC and polyvinyl alcohol (PVA). These polymer nanocomposites had excellent tensile and thermal properties. Crosslinking of PVA using glutaraldehyde (GA) not only increased the mechanical and thermal properties but the water-resistance. Chapter 4 describes the development and …
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Microrheology and microstructure of poly(vinyl alcohol)-based physical gels
… of physically cross-linked poly(vinyl alcohol) (PVA) gels using atomic force microscopy, dynamic light scattering and particle tracking. We compare the microscopic rheological properties with the bulk properties measured using conventional shear rheometry, and correlate the rheological properties …
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Preparação e caracterização de blendas formadas por goma xantana e poli (alcóol vinílico) para aplicação na área de liberação controlada de fármacos.
… xanthan ( GX ) and poly ( vinyl alcohol ) ( PVA ) chemically crosslinked with citric acid (CA ) for further application in controlled release of drugs . Infrared analysis showed possible interactions between the polymers in the blend and the incorporation of crosslinker into the polymer …
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