Synthesis and characterization of castor oil-based branched polyols from renewable resources and their polyurethane-urea coatings / Allauddin Shaik in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 16, N° 2 (03/2019)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 16, N° 2 (03/2019) . - p. 387-400 Titre : Synthesis and characterization of castor oil-based branched polyols from renewable resources and their polyurethane-urea coatings Type de document : texte imprimé Auteurs : Allauddin Shaik, Auteur ; Kabir Baidya, Auteur ; Kirankumar M. Nehete, Auteur ; Subarna Shyamroy, Auteur Année de publication : 2019 Article en page(s) : p. 387-400 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Anhydride succinique Caractérisation Copolymère uréthane-urée Gonflement (physique) Huile de ricin et constituants Polymères -- Synthèse Polymères ramifiés Polyols Polyuréthanes Transition vitreuse Index. décimale : 667.9 Revêtements et enduits Résumé : The chemical modifications of castor oil (CO) to develop branched polyols and their polyurethane-urea coatings have been investigated. For this purpose, castor oil-based branched polyols (COBPs) were synthesized from CO by modifying with succinic anhydride followed by reaction with hydroxyl group moieties like petrochemical-based pentaerythritol, trimethylolpropane and bio-based glycerol. The COBPs were characterized by using Fourier transform infrared, 1H and 13C nuclear magnetic resonance spectroscopies, gel permeation chromatography and differential scanning calorimetry. These COBPs were further urethanized with isophorone diisocyanate at OH/NCO ratio of 1:1.6 to get the isocyanate-terminated polyurethane prepolymers. The surplus isocyanate groups of the prepolymer were cured with atmospheric moisture at ambient temperature condition to form uniform film with fast surface drying. The thermo-mechanical, viscoelastic and swelling properties were evaluated for the cured coating films. Properties have been discussed from the viewpoint of branched network and also the urethane segment present in the structure. The glass transition temperatures of the coating films were found to be in the range of 32–64°C. The modified castor oil coating films show better thermo-mechanical and viscoelastic properties in comparison with control (unmodified castor oil) coating films. This work delivers an effective and promising way to synthesize branched moieties in plant oil-based high performance coatings. Note de contenu : - EXPERIMENTAL SECTION : Materials - METHODS : Synthesis of acid-terminated castor oil (COSA) - Synthesis of castor oil-based branched polyols (COBPs) - CHARACTERIZATION : Structural analysis of CO, COSA and COBPs - Drying time - DMA analysis - Swelling properties - TGA analysis DOI : 10.1007/s11998-018-0118-8 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-018-0118-8.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32411 [article]

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Synthesis and properties of siloxane-crosslinked polyurethane-urea/silica hybrid films from castor oil / Allauddin Shaik in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 11, N° 3 (05/2014)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 11, N° 3 (05/2014) . - p. 397-407 Titre : Synthesis and properties of siloxane-crosslinked polyurethane-urea/silica hybrid films from castor oil Type de document : texte imprimé Auteurs : Allauddin Shaik, Auteur ; Ramanuj Narayan, Auteur ; K. V. S. N. Raju, Auteur Année de publication : 2014 Article en page(s) : p. 397-407 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse thermique Antibactériens Copolymère uréthane-urée Diisocyanate d'isophorone Diols Huile de ricin et constituants Réticulants Silice La silice est la forme naturelle du dioxyde de silicium (SiO2) qui entre dans la composition de nombreux minéraux. La silice existe à l'état libre sous différentes formes cristallines ou amorphes et à l'état combiné dans les silicates, les groupes SiO2 étant alors liés à d'autres atomes (Al : Aluminium, Fe : Fer, Mg : Magnésium, Ca : Calcium, Na : Sodium, K : Potassium...). Les silicates sont les constituants principaux du manteau et de l'écorce terrestre. La silice libre est également très abondante dans la nature, sous forme de quartz, de calcédoine et de terre de diatomée. La silice représente 60,6 % de la masse de la croûte terrestre continentale. Silicones Les silicones, ou polysiloxanes, sont des composés inorganiques formés d'une chaine silicium-oxygène (...-Si-O-Si-O-Si-O-...) sur laquelle des groupes se fixent, sur les atomes de silicium. Certains groupes organiques peuvent être utilisés pour relier entre elles plusieurs de ces chaines (...-Si-O-...). Le type le plus courant est le poly(diméthylsiloxane) linéaire ou PDMS. Le second groupe en importance de matériaux en silicone est celui des résines de silicone, formées par des oligosiloxanes ramifiés ou en forme de cage (wiki). Transition vitreuse Index. décimale : 667.9 Revêtements et enduits Résumé : A novel hybrid diol (HD) crosslinker has been synthesized with hydrolyzable –Si–OR groups from 3-amino propyl trimethoxy silane and 3-glycidoxy propyl trimethoxy silane. Its chemical structure was confirmed by Fourier transform infrared spectroscopy, 1H and 13C nuclear magnetic resonance spectroscopy to introduce it as a crosslinker in the castor oil, a renewable resource, to develop functional organic inorganic hybrid coatings. A series of castor oil-based organic–inorganic hybrid materials were prepared from castor oil, isophorone diisocyanate, and the different weight percentages of synthesized HD. Dynamic mechanical thermal analysis, thermogravimetric analysis, differential scanning calorimetry, and the universal testing machine were employed to characterize the hybrid films. The measured properties were found to be strongly influenced by the weight ratio of HD to the castor oil-based polyurethanes. The glass transition temperatures (T g) for the cured hybrid films were found to be 26–72°C. Antibacterial activity, in vitro hydrolytic degradation, and swelling properties of the hybrid films have been studied. The cured hybrid films exhibited excellent antibacterial activity, which was enhanced with addition of the HD. The alkoxy silane-crosslinked castor oil-based coatings have shown better mechanical and viscoelastic properties in comparison to the control (uncrosslinked castor oil-based polyurethane-urea) coatings. The results showed that the weight percent of the HD is the main factor that controls the thermal, antimicrobial, mechanical, swelling, and degradation properties of these hybrid films. Note de contenu : - EXPERIMENTAL SECTION : Materials - Synthesis of HD - Synthesis of hybrid polyurethane films - Characterization - RESULTS AND DISCUSSION : Characterization of hybrid diol - DMTA analysis - TGA analysis - Contact angle - Swelling properties - Toluene swollen - In vitro degradation of hybrid films - Mechanical properties - Antibacterial activity DOI : 10.1007/s11998-013-9548-5 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-013-9548-5.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21459 [article]

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