Search results for " halloysite nanotubes"

showing 5 items of 15 documents

Halloysite nanotubes filled with salicylic acid and sodium diclofenac: effects of vacuum pumping on loading and release properties

2021

AbstractIn this work, we investigated the effects of the vacuum pumping on both the loading efficiencies and the release kinetics of halloysite nanotubes filled with drug molecules dissolved in ethanol. As model drugs, salicylic acid and sodium diclofenac were selected. For comparison, the loading of the drug molecules was conducted on platy kaolinite to explore the key role of the hollow tubular morphology on the filling mechanism of halloysite. The effects of the pressure conditions used in the loading protocol were interpreted and discussed on the basis of the thermodynamic results provided by Knudsen thermogravimetry, which demonstrated the ethanol confinement inside the halloysite cavi…

Sustained release Clay nanoparticles Drug loading Halloysite nanotubes Knudsen thermogravimetryMaterials scienceKineticsNanochemistryDiclofenac Sodiumengineering.materialHalloysiteThermogravimetryChemical engineeringengineeringKaoliniteMoleculeFourier transform infrared spectroscopySettore CHIM/02 - Chimica FisicaJournal of Nanostructure in Chemistry
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Palladium supported on Halloysite-triazolium salts as catalyst for ligand free Suzuki cross-coupling in water under microwave irradiation

2015

Abstract Environmental friendly halloysite-dicationic triazolium salts (second generation) obtained by subsequent click reactions of a diyne derivative in the presence of 2-azidopropyl-modified halloysite nanotubes, were used as supports for palladium catalyst. Thanks to the high triazolium loading (25%) these materials were able to support higher amount of the metal than that on the monocationic derivative (first generation). Such materials were characterized by thermogravimetric analysis, FT-IR spectroscopy and SEM investigations. The new catalytic system was employed in the ligand free Suzuki cross-coupling under microwave irradiation. A set of solvent, time and% loading of palladium was…

Thermogravimetric analysisSuzuki reactionHalloysite nanotubeInorganic chemistrychemistry.chemical_elementengineering.materialTriazolium saltHalloysiteCatalysisCatalysisMetalchemistry.chemical_compoundMulti-layered ionic liquidTriazolium salt Multi-layered ionic liquids Halloysite nanotubes Suzuki reaction MicrowavePhysical and Theoretical ChemistrySettore CHIM/02 - Chimica FisicaBiphenylProcess Chemistry and TechnologySettore CHIM/06 - Chimica OrganicaSolventchemistryvisual_artvisual_art.visual_art_mediumengineeringLeaching (metallurgy)MicrowavePalladiumJournal of Molecular Catalysis A: Chemical
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Effect of halloysite nanotubes filler on polydopamine properties

2019

Abstract Hypothesis Polydopamine (PDA) is widely used as hydrophilic coating for several applications. However, most of the methods studied to improve or manipulate PDA properties are multistep and time-consuming, and there is a need for versatile strategies aimed at controlling and modifying the properties of PDA. Experiments PDA-halloysite nanocomposites were produced under different oxidation conditions in alkaline and acidic media and were characterized by UV–visible and attenuated total refraction- Fourier Transform Infrared spectroscopies, thermogravimetric analysis, porosimetry, scanning electron microscopy, X-ray diffraction and contact angle measurements against the reference PDA p…

Thermogravimetric analysiscongenital hereditary and neonatal diseases and abnormalitiesPolydopamineMaterials scienceScanning electron microscopeeducationHalloysite nanotube02 engineering and technologyengineering.material010402 general chemistry01 natural sciencesHalloysiteBiomaterialsContact angleColloid and Surface ChemistryAdsorptionhealth services administrationSettore CHIM/02 - Chimica FisicaNanocompositeNanocompositeEnvironmental remediationPorosimetrySettore CHIM/06 - Chimica Organica021001 nanoscience & nanotechnology0104 chemical sciencesSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsMembraneChemical engineeringengineeringPolydopamine Halloysite nanotubes Nanocomposite Environmental remediation0210 nano-technology
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Halloysite nanotubes-based nanocomposites for the hydrophobization of hydraulic mortar

2021

Abstract The treatment of stone surfaces for their protection from ageing caused by natural and anthropogenic effects is an open issue in materials development for Cultural Heritage. We thought interesting to verify the suitability of a modified cellulose biofilm filled with halloysite nanotubes as wax compatibilizers to design a protecting layer. A hydraulic mortar was selected as a stone prototype. To improve the physico-chemical properties of the covering layer, wax microparticles have been incorporated to control transport, consolidation and wettability features. In particular, different application protocols have been studied, namely brushing and spraying, to assess whether the propos…

WaxMaterials scienceNanocompositeSurfaces and InterfacesGeneral Chemistryengineering.materialMicrostructureHalloysiteSurfaces Coatings and FilmsContact angleColloid and Surface ChemistryAdsorptionvisual_artStone Biopolymer Cultural heritage Halloysite nanotubes Nanocompositesengineeringvisual_art.visual_art_mediumWettingComposite materialMortarSettore CHIM/02 - Chimica FisicaJournal of Coatings Technology and Research
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Application of Broadband Dielectric Spectroscopy to Cultural Heritage: characterization and preservation of ancient paper artwork

2016

Within the cultural heritage the characterization and conservation of artworks based on paper represents a significant issue for both restorers and scientists. The paper deterioration is affected by the degree of hydrolytic and oxidative reactions which occur upon aging. Moreover, the durability of cellulose fibers depends on the intrinsic composition/structure of the paper as well as on the conservation conditions, such as temperature and humidity. The structural and dynamical characterization of the cellulose matrix and of the water confined within its pores is therefore of central interest. Our working hypothesis is that WATER DYNAMICS is one of the main determinants of paper degradation…

paper artworks characterization conservation cellulose matrix confined water water dynamics halloysite nanotubes broadband dielectric spectroscopySettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)
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