Network formation and thermo-mechanical properties of photo-curing hybrid coatings / Ahmet Nebioglu / 2006  

Titre : Network formation and thermo-mechanical properties of photo-curing hybrid coatings Type de document : texte imprimé Auteurs : Ahmet Nebioglu, Auteur ; Graduate Faculty of the University of Akron (Akron, Ohio - United State), Organisme de soutenance Année de publication : 2006 Importance : XVII-169 p. Présentation : ill. Format : 30 cm Note générale : Bibliogr. Catégories : Matériaux hybrides -- Propriétés thermomécaniques Polyesters Réticulation (polymérisation) Thèses et écrits académiques Index. décimale : 667.9 Revêtements et enduits Résumé : UV-moisture dual curable inorganic/organic hybrid coatings based on unsaturated polyester binders and silicate-clusters were successfully prepared. In situ formed nano to micro size inorganic clusters increased the abrasion resistance, adhesion, tensile strength and fracture toughness of the films. Free radical UV-crosslinking process was used to form the organic phase. An isocyanate functional alkoxysilane coupling agent was used to connect organic and inorganic phases.The effects of the silicate groups on the free radical photo-curing reaction kinetics were investigated utilizing a time-resolved Fourier transform infrared (FT-IR) spectroscopy and a differential scanning calorimeter equipped with a photocalorimetric accessory (photo-DSC). Inorganic network formation during the UV-initiated free radical crosslinking reactions was suggested to describe the complex gel-point behavior. It was proposed that inorganic silicate groups retard the organic crosslinking reactions. In order to depict the interaction of the silicate clusters and organic network formation, it was necessary to characterize the organic network structure. Therefore, a series of methods including dynamic mechanical thermal analysis and dynamic light scattering were utilized to understand the nature of the organic crosslinking reactions. The effect of the placement, i.e. whether internal or terminal, of the unsaturation on the polyester chains and concentration of the reactive monomer on the network structure formation was investigated. It was found that intramolecular cyclization reactions were detrimental in the network structure, and hence final film properties. Inclusion of the silicate groups inhibit the intramolecular cyclization reactions, and therefore affect the organic network structure formation. The UV-cured inorganic/organic hybrid films showed more homogeneous film morphology compared to the organic counterparts. In hybrid films a core-shell like inorganic/organic particle morphology was observed. The UV-crosslinked organic part forms the inside core, whereas the inorganic silicate part forms the surrounding shell. Network formation mechanism and film properties were extensively changed with the formation of these colloidal particles. Thèse : Thèse. Spécialité Génie chimique : University of Akron - Akron (USA) - 2006 En ligne : https://etd.ohiolink.edu/rws_etd/document/get/akron1145166725/inline Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29886

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Processing of polyetherimide/cloisite 30B nanocomposite by vibration casting method / M. Dwivedi in INTERNATIONAL POLYMER PROCESSING, Vol. XXIX, N° 5 (11/2014)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XXIX, N° 5 (11/2014) . - p. 635-640 Titre : Processing of polyetherimide/cloisite 30B nanocomposite by vibration casting method Type de document : texte imprimé Auteurs : M. Dwivedi, Auteur ; K. K. Gaur, Auteur ; S. Alam, Auteur ; Naresh Bhatnagar, Auteur ; A. K. Ghosh, Auteur Année de publication : 2014 Article en page(s) : p. 635-640 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cloisite Diméthylacétamide Matériaux hybrides -- Propriétés thermomécaniques Polyéther imide Vibrations (mécanique) Index. décimale : 668.9 Polymères Résumé : Vibration casting method was developed for making polyetherimide (PEI)/Cloisite 30B nanocomposite. Towards this, a vibration casting apparatus was designed and developed. Vibration casting apparatus provided vibrational energy and heat, simultaneously. The processing parameters were established for vibration casting in terms of frequency of vibration, temperature, time and viscosity of casting mixture. Casting mixture of PEI/Cloisite 30B/N,N-dimethyl acetamide (DMAc) was made by dissolving PEI in DMAc and then mixing Cloisite 30B in this solution. The viscosity of PEI/Cloisite 30B/DMAc mixture was optimized for casting by controlling the volume fraction of PEI in DMAc. Morphology of PEI/Cloisite 30B nanocomposite was examined by wide angle X-ray diffraction, transmission electron microscopy, scanning electron microscopy and contact angle measurement. Mechanical and thermal properties of PEI/Cloisite 30B nanocomposite were also compared with that of neat PEI to ascertain the efficacy of vibration casting method. Note de contenu : - EXPERIMENTAL : 1. Materials - 2. Design and Development of Vibration Casting Apparatus - 3. Optimisation of Viscosity - 4. Estimation of Frequency - 5. Processing of PEI/Cloisite 30B Nanocomposite - 6. Evaluation of Morphology - 7. Evaluation of Mechanical and Thermal Properties - RESULTS AND DISCUSSION : 1. Optimisation of Viscosity for Casting Mixture - 2. Frequency of Vibration to Cast PNC Film - 3. Morphology - 4. Mechanical and Thermal Properties DOI : 10.3139/217.2952 En ligne : https://drive.google.com/file/d/13ZlgK1wxyMJJC5UIE9yB6Xk1I2VR7oRr/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=22243 [article]

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