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Model compound study for acrylic latex crosslinking reactions with cycloaliphatic epoxides / Shaobing Wu in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 69, N° 869 (06/1997)
[article]
Titre : Model compound study for acrylic latex crosslinking reactions with cycloaliphatic epoxides Type de document : texte imprimé Auteurs : Shaobing Wu, Auteur ; Mark D. Soucek, Auteur Année de publication : 1997 Article en page(s) : p. 43-49 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Copolymères
Epoxydes
Latex
Polyacryliques
Polymères aliphatiques
Réticulation (polymérisation)Tags : 'Acrylique acide copolymère' 'Méthacrylate d'hydroxyéthyle' Latex Réticulation Epoxyde 'Composé bicyclique' 'Réaction modèle' Cinétique 'Mécanisme réaction' Régiosélectivité 'Effet température' pH Stoechiométrie Index. décimale : 667.9 Revêtements et enduits Résumé : Cyclohexene oxide, methanol, and acetic acid were used as model compounds to study the competitive crosslinking of cycloaliphatic diepoxides with hydroxyl and carboxyl functionalized acrylic copolymers. Model reactions were performed as a function of molar ratio, pH, and temperature. At a 2:1:1 molar ratio of epoxide: hydroxyl: carboxyl, the formation of the primary ether and ester linkages were found to be the major crosslinking reactions. By increasing the molar ratio to 3:1:1, the formation of both the ether and ester oligomer products were significantly enhanced. As the pH of the media decreased, the rate of the crosslinking reactions increased, and generally ester products were formed preferentially to ether products. A temperature dependence of the rate of reactions were generally more pronounced at higher pH. Note de contenu : - EXPERIMENTAL SECTION : Materials - Instrumentation - General procedure for model reactions - Sampling and GC analysis
- RESULTS AND DISCUSSION : Model compound products and molar ratio effect on product formation - pH effect on the formation of primary and secondary ether and ester products - Temperature effect on the formation of primary and secondary products - Proposed crosslinking modes for cycloaliphatic epoxides with hydroxyl and carboxyl functionalized acrylic copolymersPermalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18245
in JOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 69, N° 869 (06/1997) . - p. 43-49[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 003538 - Périodique Bibliothèque principale Documentaires Disponible The selectivity of isophorone diisocyanate in the urethane reaction / R. Lomoelder in PAINTINDIA, Vol. XLVIII, N° 11 (11/1998)
[article]
Titre : The selectivity of isophorone diisocyanate in the urethane reaction : Influence of temperature, catalysis and reaction partners Type de document : texte imprimé Auteurs : R. Lomoelder, Auteur ; F. Plogmann, Auteur ; P. Speier, Auteur Année de publication : 1998 Article en page(s) : p. 31-38 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Polyuréthane' 'Diisocyanate organique' 'Cyclohexane dérivé' Polyaddition Diol 'Réaction catalytique' modèle' 'Activité 'Sélectivité catalyseur' Régiosélectivité 'Acide Lewis' 'Métal Composé' 'Base 'Amine tertiaire' 'Effet température' 'Etude expérimentale' comparative' Index. décimale : 667.9 Revêtements et enduits Résumé : The selectivity of isophorone diisocyanate (IPDI) in the urethane reaction demonstrates a strong dependence on temperature, catalyst type, and degrees of substitution of the reaction partner. It was possible to establish, by means of GC analysis of the monomer content, that dibutyltin dilaurate (DBTL) leads to the highest selectivity compared to the series of Sn, Zn, Bi, Fe, and amine catalysts. The ratio ofthe rate constant Γin the model reaction with 1-butanol at 20°C was increased from 5.5 in the uncatalyzed variant to 11.5 by catalysis with DBTL. The use of diazabicyclooctane succeeded in reversing the selectivity. The selectivity under DBTL catalysis dropped from 11.5 at 20°C to 6.5 at 100°C. The use of 2-butanol leads to a further increase in selectivity: Γ= 17 with DBTL catalysis at 20°C. By the resolution of all four monourethanes by GC analysis of the 1-butanol reaction, a significantly higher selectivity of trans IPDI was established: the ratio of secondary monourethane to primary monourethane with trans IPDI is higher by a factor of 2. A very good correlation between prepolymer synthesis and the model reactions was observed. Recommended optimal conditions for prepolymer synthesis based on IPDI are temperatures between 40°C to 60°C using DBTL catalysis. Note de contenu : - Selectivity of IPDI by application of various urethane catalysts
- Influence of temperature on the selectivity of IPDI - Additional steric hindrance : 2-butanol - Back to the pratical : NCO prepolymersPermalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=13179
in PAINTINDIA > Vol. XLVIII, N° 11 (11/1998) . - p. 31-38[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 006481 - Périodique Bibliothèque principale Documentaires Disponible