On the stratification mechanism of self-stratifying epoxy–acrylic coatings / Ali Abbasian in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 18, N° 2 (03/2021)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 18, N° 2 (03/2021) . - p. 559-568 Titre : On the stratification mechanism of self-stratifying epoxy–acrylic coatings Type de document : texte imprimé Auteurs : Ali Abbasian, Auteur ; S. Ekbatani, Auteur ; N. Bagherzadeh, Auteur Année de publication : 2021 Article en page(s) : p. 559-568 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Copolymère époxy acrylique Enrobage (technologie) Epaisseur -- Mesure Marangoni, Effet Revêtements autostratifiants Revêtements organiques Index. décimale : 667.9 Revêtements et enduits Résumé : To shed light on the self-stratification mechanism in epoxy–acrylic coatings, 200-, 400-, and 800-micron-thick coatings were applied on glass and aluminum substrates, and their solidification behavior was studied. Some of the applied coats showed self-stratification behavior, with the thermoplastic acrylic copolymer in the top layer. In addition, experiments were performed on epoxy–acrylic solutions without hardeners to evaluate the resulting convective patterns on the solution surface, which exhibited finger-type convection. The final structure of the films had an apparent dependency on the thickness. Thicker films were usually more stratified and had a thicker stratified layer. As these observations could not support diffusion as the primary mechanism of self-stratification, convection experiments were done on epoxy and coatings solutions. The surface patterns on the solutions were studied, and the finger-type convection was observed. Based on these observations, we propose that convection may be the primary movement mechanism rather the diffusion of polymers toward the surface in the self-stratifying coats. Note de contenu : - Experimental - Results and discussion : Self-stratification tests - Thickness effect - Effect of substrate - Convection experiments in resin solutions - Table 1 : Specifications of curing agents - Table 2 : Specifications of acrylic copolymers DOI : https://doi.org/10.1007/s11998-020-00424-2 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-020-00424-2.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35615 [article]

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Preparation of high-performance epoxy soybean oil-based UV-curable oligomers and coatings / Yumei Zhou in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 20, N° 6 (11/2023)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 20, N° 6 (11/2023) . - p. 1923-1933 Titre : Preparation of high-performance epoxy soybean oil-based UV-curable oligomers and coatings Type de document : texte imprimé Auteurs : Yumei Zhou, Auteur ; Linxi Feng, Auteur ; Jinqing Qu, Auteur Année de publication : 2023 Article en page(s) : p. 1923-1933 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse structurale (ingénierie) Copolymère époxy acrylique Copolymères -- Synthèse Huile de soja Oligomères Revêtements -- Propriétés mécaniques Revêtements -- Propriétés thermiques Revêtements -- Séchage sous rayonnement ultraviolet Revêtements organiques Traction (mécanique) Index. décimale : 667.9 Revêtements et enduits Résumé : Ultraviolet (UV)-curable coatings made from acrylated epoxy soybean oil (AESO) combine the advantages of renewable biobased resources and energy-efficient UV-curable materials, so they serve as the primary research objects for developing eco-friendly coatings. However, due to the lack of rigid structure, the hardness and thermal stability of AESO are much lower than those of petroleum-based epoxy acrylate (EA). Therefore, high-performance soybean oil-based UV-curable oligomers were prepared by using dimethylolpropionic acid (DMPA) and methacrylic anhydride (MAAH) to modify ESO and then blended with high-functional active diluent trimethylolpropane triacrylate (TMPTA). Furthermore, FTIR, 1H NMR, and GPC were used to analyze the molecular structure and molecular weight of the oligomers. The oligomers (DMA/MAAESO and DMA/MAAESO-TM) had high esterification rate, curing degree, and good storage stability. The cured coatings from DMA/MAAESO and DMA/MAAESO-TM oligomers had significantly improved thermal stability, tensile, and coating properties. In all samples, DMA/MAAESO-TM cured coating had excellent coating performances. The glass transition temperature (Tg) of DMA/MAAESO-TM was 78.1°C, and its crosslink density (νe) was 6.87 × 10−3 mol/cm3. The hardness, curing time, gloss, flexibility, and impact resistance were H, 20 s, 108.5, 1 mm, and 50 cm, respectively. Note de contenu : - EXPERIMENTAL : Materials - Synthesis of acrylate epoxy soybean oil (AESO) - Synthesis of DMA/MAA - Synthesis of DMA/MAAESO - Preparation of AESO and DMA/MAAESO coatings - Characterization - RESULTS AND DISCUSSION : Synthesis of DMA/MAA and DMA/MAAESO - Structural analysis of AESO and DMA/MAAESO - GPC of AESO and DMA/MAAESO - Physical properties of UV-curable oligomers - Dynamic mechanical analysis of UV-curable coatings - Thermogravimetric analysis of UV-curable coatings - Tensile properties of UV-curable coatings - Coating film properties - Table 1 : Physical properties of oligomers - Table 2 : Dynamic mechanical properties of UV-curable coatings - Table 3 : Thermal properties of UV-curable coatings - Table 4 : Tensile properties of UV-curable coatings - Table 5 : Coating film propertiesTable 6 Comparison of the DMA/MAAESO-TM with other samples in the literature DOI : https://doi.org/10.1007/s11998-023-00787-2 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-023-00787-2.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40171 [article]

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Preparation of low viscosity and high flexibility epoxy acrylate and its application in UV-curable coatings / Yumei Zhou in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 21, N° 2 (03/2024)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 21, N° 2 (03/2024) . - p. 601-610 Titre : Preparation of low viscosity and high flexibility epoxy acrylate and its application in UV-curable coatings Type de document : texte imprimé Auteurs : Yumei Zhou, Auteur ; Jinqing Qu, Auteur Année de publication : 2024 Article en page(s) : p. 601-610 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Copolymère époxy acrylique Copolymères -- Synthèse Oligomères Revêtements -- Propriétés mécaniques Revêtements -- Séchage sous rayonnement ultraviolet Souplesse (mécanique) Thermodurcissables Viscosité Index. décimale : 667.9 Revêtements et enduits Résumé : Epoxy acrylate (EA) is currently the most widely used UV-curable oligomer due to its short curing time, high coating hardness, excellent mechanical property, and thermal stability. To address the problems of high brittleness, poor flexibility, and high viscosity of EA, the UV-curable epoxy acrylate oligomer with low viscosity and high flexibility was prepared and applied to UV-curable coatings. The carboxyl terminated intermediate obtained by the reaction of anhydride and diol was used to modify EA to improve the flexibility of cured film, and the flexibility was adjusted through the length of the carbon chain of diols. The resin viscosity was reduced by partially replacing E51 with binary glycidyl ether. Compared with unmodified EA, the viscosity of the resin prepared in this study decreases from 29800 to 13920 mPa s (25°C), and the flexibility of the cured film increases from 12 to 1 mm. Compared with commercially available modified EA, the raw materials used in this study are low cost and easy to obtain with a reaction temperature below 130°C, using a simple synthesis process, and no organic solvents. Note de contenu : - EXPERIMENT : Raw materials - Synthesis of EA - Synthesis of MHEA - Preparation of UV-cured film - Characterization - Acid value (A v) - Viscosity (V s) - Fourier transform infrared spectroscopy (FTIR) - 1H nuclear magnetic resonance (1H NMR) - Gel permeation chromatography (GPC) - Gel rate of curing film (C gel) - Thermogravimetric analysis (TGA) - Tensile properties testing - Curing time testing - Coating film properties testing - RESULTS AND DISCUSSION : Determination of reaction conditions - Determination of the type of diols - Determination of the type of acid anhydrides - Determination of BDDGE addition amount - Structural analysis of MHEA - Curing process of UV-curable coatings - Thermogravimetric analysis of the cured films - Tensile properties of the cured films - UV-curable coating properties - Table 1 : Effect of kinds of diols on properties of the resin and cured film - Table 2 : Effect of kinds of anhydrides on properties of the resin and cured film - Table 3 : Effect of BDDGE addition on the properties of the resin and cured film - Table 4 : GPC results of E51 and MHEA - Table 5 : TG results of cured film prepared by EA and MHEA - Table 6 : Tensile properties of the EA and MHEA cured films - Table 7 : Comparison of cured film properties DOI : https://doi.org/10.1007/s11998-023-00842-y En ligne : https://drive.google.com/file/d/1PLtHKXgXPTsptg2OK9_saRrfjeXqQFns/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40780 [article]

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