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A kinetic study of the reaction of epoxidized rubber and carboxylic acids / J. Kyle Copeland in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 66, N° 833 (06/1994)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 66, N° 833 (06/1994) . - p. 59-62 Titre : A kinetic study of the reaction of epoxidized rubber and carboxylic acids Type de document : texte imprimé Auteurs : J. Kyle Copeland, Auteur ; Shelby F. Thames, Auteur Année de publication : 1994 Article en page(s) : p. 59-62 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Acides carboxyliques Caoutchouc Cinétique chimique Epoxydes Réactions chimiques Réticulants Revêtements -- Additifs:Peinture -- Additifs Index. décimale : 667.9 Revêtements et enduits Résumé : The coatings industry has long been interested in non-toxic multifunctional crosslinking agents that do not emit volatile organic compounds (VOCs) during curing. Ring opening of epoxides is an ideal chemical reaction for there are no accompanying VOCs. Therefore, we have investigated the feasibility of a novel epoxide reagent as a multifunctional crosslinking agent. Specifically, epoxidized poly-cis-isoprene has been synthesized and evaluated as a reactant with a variety of carboxylic acids via isothermal differential scanning calorimetry. Accordingly, we have measured the reaction enthalpy at various temperatures and reactant concentrations. The change in heat flow with time is proportional to the change in the reactant concentration with time since ring opening of epoxides with carboxylic acids gives chain modification via ester formation. We have also determined the reaction order and energy of activation. Three acids ranging in pKa from 1.26 to 4.95 were studied and provided activation energies ranging from 42.9 to 115.9 kJ/mol. The reaction order was determined to be first order in acid. Note de contenu : - EXPERIMENTAL : Materials - Preparation of epoxidized rubber - Preparation of DSC samples - DSC analysis - RESULTS AND DISCUSSION : Reaction order - Energy of activation - Comparison of the acids Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18642 [article]

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Film formation from conventional and miniemulsion latex systems containing dimethyl meta-isopropenyl benzyl isocyanate (TMI) - a functional monomer/crosslinking agent / Yoshimi Inaba in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 66, N° 833 (06/1994)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 66, N° 833 (06/1994) . - p. 63-74 Titre : Film formation from conventional and miniemulsion latex systems containing dimethyl meta-isopropenyl benzyl isocyanate (TMI) - a functional monomer/crosslinking agent Type de document : texte imprimé Auteurs : Yoshimi Inaba, Auteur ; Eric S. Daniels, Auteur ; Mohamed S. El-Aasser, Auteur Année de publication : 1994 Article en page(s) : p. 63-74 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Copolymère styrène acrylate de butyle Formation de film Isocyanates Polymérisation en émulsion Réticulants Revêtements en phase aqueuse:Peinture en phase aqueuse Index. décimale : 667.9 Revêtements et enduits Résumé : A series of model styrene (St)/n-butyl acrylate (BA) copolymer latexes with glass transition temperatures below room temperature were prepared by either conventional or miniemulsion polymerization techniques as model systems for studies of film formation. The functional monomer TMI® (META) (dimethyl meta-isopropenyl benzyl isocyanate) was used as a functional monomer/crosslinking agent. A small amount of methacrylic acid (MAA) was introduced in some formulations to enhance the crosslinking reactions. A redox initiation system was used to reduce premature crosslinking during the polymerization. A combination of an ionic surfactant (sodium lauryl sulfate) and co-surfactant (hexadecane or cetyl alcohol) was used as the mixed emulsifier for the miniemulsion system. This paper describes the performance of TMI as a crosslinking agent and the effects of the combination of TMI and MAA on the latex film formation process. Note de contenu : - EXPERIMENTAL : Materials - Miniemulsification - Polymerization - Evaluation methods - RESULTS AND DISCUSSION : Effect of the crosslinking agent concentration - Effect of initiator concentration - Effect of BA/St ratio - Influence of emulsifier concentration and differences between mixed emulsifier systems - Differences between latex film dried from St/BA/TMI/MAA copolymer latex and a blend of St/BA/TMI with St/BA/MAA copolymer latexes with varying TMI/MMA ratios Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18643 [article]

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High-solids coatings using benzylanilinium sulfonates / T. Morimoto in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 66, N° 833 (06/1994)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 66, N° 833 (06/1994) . - p. 75-82 Titre : High-solids coatings using benzylanilinium sulfonates Type de document : texte imprimé Auteurs : T. Morimoto, Auteur ; Shinji Nakano, Auteur Année de publication : 1994 Article en page(s) : p. 75-82 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Ammonium Aniline Cations Haut extrait sec Mélamine La mélamine, de nom chimique 1,3,5-triazine-2,4,6-triamine, est parfois dénommée cyanuramide ou cyanurotriamine. Sa formule brute est C3H6N6. Les "résines mélamine-formaldéhyde" ou "mélamine-formol" (sigle MF) sont appelées "mélamine" dans le langage courant. Elles font partie de la famille des aminoplastes qui regroupe des résines thermodurcissables aminées, issues d'un comonomère tel l'urée ou la mélamine, parfois le thiocarbamide, le cyanamide hydrogène ou le dicyandiamide ; le second comonomère étant le formaldéhyde. Réticulants Revêtements:Peinture Stabilité au stockage Index. décimale : 667.9 Revêtements et enduits Résumé : Benzylanilinium sulfonates (1n) were synthesized by reacting benzylchloride with N,N-dimethylaniline, followed by the exchange of Cl- with RSO3-. Benzylanilinium sulfonates reacted with H2O, releasing sulfonic acid only at temperatures greater than 75°C, although this temperature varied according to the p-substituents on the 1n benzyl group. Clear coating solutions, consisting of an acrylic polyol, hexamethoxymethylmelamine (HMMM), and 1n, gave cured films over 125°C. Note de contenu : - EXPERIMENTAL : Synthesis of 1n - Synthesis of amine blocked p-TSA (2n) - Estimation of 1n unblocking temperatures - Synthesis of acrylic polyol - Formulation of clear coating solutions - Measurement of pH of the aqueous solutions - Evaluation of storage stability - Evaluation of crosslinking reaction - RESULTS AND DISCUSSION : Synthesis of benzylanilinium sulfonates (1n) - Reaction of 1d with H2O - Estimation of unblocking temperatures of 1n - Properties of coating solutions - Effect of 1n on crosslinking reaction - Effect of unblocking temperatures of 1n on crosslinking reaction - Storage stability of clear coating solutions - Application of benzylanilinium sulfonates to short-time curable coatings Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18644 [article]

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Hygrothermal stress evolution during weathering in organic coatings / Dan Y. Perera in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 66, N° 833 (06/1994)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 66, N° 833 (06/1994) . - p. 83-88 Titre : Hygrothermal stress evolution during weathering in organic coatings Type de document : texte imprimé Auteurs : Dan Y. Perera, Auteur ; Maarten Oosterbroek, Auteur Année de publication : 1994 Article en page(s) : p. 83-88 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Contraintes (mécanique) Copolymère acrylique mélamine Copolymère uréthane acrylique Essais accélérés (technologie) Relaxation des contraintes Vernis -- Effets du climat Index. décimale : 667.9 Revêtements et enduits Résumé : Hygrothermal stresses developing in two clearcoats exposed to two types of accelerated weathering were determined. The physical and chemical changes induced by weathering produce a continuous increase of tensile and compressive stresses which ultimately causes it to crack. It was found that the stress magnitude and the duration of exposure at which the coating cracks depend on the type of the accelerated weathering. Also, the rate of stress relaxation decreases with duration of weathering. However, the shape of curves describing the stress dependence on duration of weathering is the same provided that the main mechanism of coating degradation does not change. When combined with other techniques, the measurement of stress appears to be an important way of studying coating durability (...) Note de contenu : - EXPERIMENTAL: Materials - Accelerated Wheathering - Methods - RESULTS : Physical aging - Type of accelerated Wheathering - Stress relaxation Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18652 [article]

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