Optical and temperature dependent electrical properties of poly (vinyl chloride)/copper alumina nanocomposites for optoelectronic devices / S. Suvarna in INTERNATIONAL POLYMER PROCESSING, Vol. 38, N° 2 (2023)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. 38, N° 2 (2023) . - p. 154-156 Titre : Optical and temperature dependent electrical properties of poly (vinyl chloride)/copper alumina nanocomposites for optoelectronic devices Type de document : texte imprimé Auteurs : S. Suvarna, Auteur ; Annumaria Sebastian, Auteur ; Furhan, Auteur ; Manammel Thankappan Ramesan, Auteur Année de publication : 2023 Article en page(s) : p. 154-156 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Alumine Caractérisation Chlorure de polyvinyle Composites -- Propriétés optiques Cuivre Diélectriques Matériaux hybrides Modèles mathématiques Stabilité thermique Thermocinétique Index. décimale : 668.4 Plastiques, vinyles Résumé : The practical applications of poly (vinyl chloride) have been constrained due to its poor thermal stability, low dielectric constant and inability to shield against ultraviolet (UV) radiation. In this study, we tried to improve the optical properties, thermal stability, temperature-dependent electrical conductivity and dielectric constant using copper alumina (Cu–Al2O3) nanoparticles reinforced poly (vinyl chloride) (PVC). Optical absorption measured with an ultraviolet-visible (UV-visible) spectrometer emphasises the blueshift in absorption edges and decreasing bandgap energies of PVC/Cu–Al2O3 nanocomposites compared to PVC. The presence of Cu–Al2O3 in PVC and its interaction with the polymer were confirmed by FTIR spectroscopy. Thermogravimetric analysis (TGA) demonstrates that nanocomposites have higher thermal stability than PVC, and that thermal stability increases with filler loading. Scanning electron microscopy (SEM) indicates the homogeneous dispersion of nanosized Cu–Al2O3 in the polymer matrix. The activation energy determined by the Arrhenius equation revealed that AC conductivity increases with the addition of nanoparticles up to a specific loading. The dielectric constant increases as a function of temperature and decreases with frequency. The magnitude of AC conductivity and dielectric constant were highest for 7 wt% loaded nanocomposites. The dielectric constant predicted by the Bruggeman and Maxwell-Garnet models were in good agreement with the experimental permittivity. The semiconducting nature of nanocomposites was investigated by impedance analysis. The semi-circular nature of Cole-Cole plots manifests the combination of parallel capacitance with low bulk resistance. The enhanced optical, thermal, electrical and dielectric properties of PVC/Cu–Al2O3 nanocomposites can be utilized in fabricating optoelectronic devices with excellent charge-storing ability. Note de contenu : - EXPERIMENTAL : Materials and methods - Synthesis of copper alumina nanoparticles - Preparation of poly (vinyl chloride)/copper alumina nanocomposites - Characterizations - RESULTS AND DISCUSSION : UV-visible spectroscopy - Optical bandgap energy - Fourier transform IR spectroscopy - SEM analysis - Thermogravimetric analysis - AC conductivity - Dielectric constant - Dielectric modelling - Impedance studies - Table 1 : Activation energy of PVC/Cu–Al2O3 nanocomposites at different frequencies DOI : https://doi.org/10.1515/ipp-2022-4270 En ligne : https://drive.google.com/file/d/1PiSW7w4CgwZjlcALwPviqWqCkaTm2GKW/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39498 [article]

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The effect of nanosilicates on the performance of polyethylene terephthalate films prepared by twin-screw extrusion / A. Ghanbari in INTERNATIONAL POLYMER PROCESSING, Vol. 36, N° 4 (2021)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. 36, N° 4 (2021) . - p. 358-366 Titre : The effect of nanosilicates on the performance of polyethylene terephthalate films prepared by twin-screw extrusion Type de document : texte imprimé Auteurs : A. Ghanbari, Auteur ; M.-C. Heuzey, Auteur ; Pierre J. Carreau, Auteur Année de publication : 2021 Article en page(s) : p. 358-366 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caractérisation Composites -- Propriétés mécaniques Composites -- Propriétés optiques Composites -- Propriétés thermiques Extrudeuse bi-vis Matières plastiques -- Extrusion Montmorillonite Nanoparticules Polyéthylène téréphtalate Silicates Index. décimale : 668.4 Plastiques, vinyles Résumé : Polyethylene terephthalate (PET) films were prepared by cast extrusion using a twin-screw extruder with a severe screw profile. The effect of an organically modified montmorillonite on thermal, mechanical, optical, and barrier properties of the PET films were investigated. Morphological characterization of the nanocomposite films was performed by employing wide angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) followed by image analysis. The results unfold a mixed morphology for the nanocomposite films with more than 95% exfoliated and intercalated silicate layer structures, depending on the screw rotation speed. The remarkable dispersion of the organoclay particles at the nano-level is discussed in terms of solubility parameter and favorable interactions between PET macromolecules and organic modifier of the nanoclay. The crystal content of the nanocomposite films and their cold and hot crystallization temperatures confirmed the role of silicate nanolayers as a heterogeneous nucleating agent. While all nanocomposite films exhibit higher haze values in comparison to the neat PET samples, incorporation of 2 wt% nanoclay brought about 25% increase in tensile modulus and barrier properties. A range of screw rotation speeds with optimized properties in terms of haze, morphology, thermal, mechanical, and barrier properties is suggested. Note de contenu : - Materials - Sample preparation - Characterization - Table 1 : DSC analysis results of the neat PET and nanocomposite films at various screw rotation speeds DOI : https://doi.org/10.1515/ipp-2020-4044 En ligne : https://drive.google.com/file/d/1UF1Q7xDZbldM1DEaaAvzkMvJsgouDJwq/view?usp=shari [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36708 [article]

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