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Synthesis of acrylic resins for high-solids coatings by solution and separation polymerization / Constantinos D. Diakoumakos in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 908 (09/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 908 (09/2000) . - p. 61-70 Titre : Synthesis of acrylic resins for high-solids coatings by solution and separation polymerization Type de document : texte imprimé Auteurs : Constantinos D. Diakoumakos, Auteur ; Qi Xu, Auteur ; Frank N. Jones, Auteur ; Jamil A. Baghdachi, Auteur Année de publication : 2000 Article en page(s) : p. 61-70 Note générale : Bibliogr. Langues : Américain (ame) Tags : Matériau  revêtement  Peinture  haute  teneur  solide  Vernis  Liant  Acrylique  dérivé  polymère  Préparation  Polymérisation  radicalaire  solution  Caractérisation  Etude  expérimentale Index. décimale : 667.9 Revêtements et enduits Résumé : Conventional solution polymerization under monomer-starved conditions was compared with separation polymerization, also known as monomer-starved, as a method for making acrylic resins with low polydispersity (D=Mw/Mn). Separation polymerization employs aliphatic or cycloaliphatic solvents that are good solvents for the monomers but poor solvents for the resin; thus, the resin separates during polymerization. Various process conditions, initiators, chain-transfer agents, and solvents were studied, focusing mainly on a monomer line-up of methyl methacrylate, styrene, ethyl acrylate, and 2-hydroxy ethyl methacrylate in a 15/15/40/30 weight ratio. Two initiators, t-amyl peroxy 2-ethyl hexanoate and t-butyl peroxy 2-ethyl hexanoate gave about equal, excellent results. 2-Mercapto ethanol was selected as a chain transfer agent. With these ingredients, the separation polymerization method is capable of producing oligomeric acrylic polyol resins with polydispersities (D) of about 1.7 to 1.8 when Mn is in the range 1350 to 1600. These resins have substantially lower solution viscosities than a commercial benchmark resin, which has Mn=1230 and D=2.03. In preliminary tests of 2K polyurethane coatings, the film properties obtained with acrylics made by separation polymerization were, on balance, superior to those obtained with a commercial benchmark resin. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5788 [article]

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Effects of reaction conditions on the formation of poly(2-vinylpyridine) coatings by electropolymerization / Xiaoping Ling in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 908 (09/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 908 (09/2000) . - p. 71-80 Titre : Effects of reaction conditions on the formation of poly(2-vinylpyridine) coatings by electropolymerization Type de document : texte imprimé Auteurs : Xiaoping Ling, Auteur ; Mark D. Pritzker, Auteur ; Charles M. Burns, Auteur ; John J. Byerley Année de publication : 2000 Article en page(s) : p. 71-80 Note générale : Bibliogr. Langues : Américain (ame) Tags : Matériau  revêtement  Procédé  Polymérisation  électrolytique  Pyridine(2-vinyl)polymère  Pyridine(2-vinyl)copolymère  Formation  film  Couche  protectrice  anticorrosion  Acier  doux  Condition  opératoire  Etude  expérimentale Index. décimale : 667.9 Revêtements et enduits Résumé : The effects of reaction conditions on the formation of poly(2-vinylpyridine) coatings on mild steel by electropolymerization have been investigated. Over the ranges studied, the relative effects of these reaction conditions on the weight of the coating produced is found to decrease as follows : monomer concentration > solution pH > methanol concentration > solution temperature. The optimum conditions for coating formation are to use a solution with a composition of 0.25 M 2-vinylpyridine, 15 vol% methanol, and pH 5.0 at a temperature of 20 °C. If the monomer concentration is too high, the coating formed is soft and tacky; if it is too low, a thin and non-uniform coating is produced. Methanol concentrations between 15 and 25 vol% are required to produce uniform and thick films. Coating weights decrease at electropolymerization temperatures above 40°C, presumably due to an increase in polymer solubility. The polymer films become thicker and more uniform as electrolysis continues up to two hours. Ammonium perchlorate is found to be the most suitable electrolyte for the process, although its actual concentration has little impact on film quality. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5789 [article]

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Advanced testing procedures for high performance coatings / Flavio Deflorian in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 908 (09/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 908 (09/2000) . - p. 81-87 Titre : Advanced testing procedures for high performance coatings Type de document : texte imprimé Auteurs : Flavio Deflorian, Auteur ; Stefano Rossi, Auteur ; Pier Luigi Bonora, Auteur Année de publication : 2000 Article en page(s) : p. 81-87 Note générale : Bibliogr. Langues : Américain (ame) Tags : Matériau  revêtement  Peinture  anticorrosion  Industrie  automobile  Protection  corrosion  Essai  brouillard  salin  Impédance  électrique  Méthode  électrochimique  Etude  comparative  expérimentale  Spectrométrie  impédance Index. décimale : 667.9 Revêtements et enduits Résumé : In the first part of this work, an integrated approach incorporating electrochemical (electrochemical impedance spectroscopy), calorimetric (differential scanning calorimetry), mechanical (dynamic mechanical thermal analysis), and infrared spectroscopy (Fourier transform infrared spectroscopy) techniques was used to characterize some organic coatings from the automotive industry. Comparison of the results obtained with different techniques allows not only a higher precision in the evaluation of natural or artificial degradation, which is very difficult to obtain using traditional techniques, but also better data interpretation and, therefore, the possibility of understanding the different degradation mechanisms. In the second part, some preliminary results concerning the comparison of salt spray exposure and EIS measurements are discussed. The statistical analysis of the results showed that the degradation mechanism in the two cases is completely different and, therefore, the information which is obtained with the two testing approaches is also different. With EIS measurements obtained in immersion, it is possible to monitor, in particular, the barrier properties of the coatings, which are dominated by the presence of defects. In the case of salt spray (without scratch), the main property to be measured is the loss of adhesion which causes blister formation. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5790 [article]

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Evaluation of alkane sulfonic acid catalysts and derivatives for curing activity in a melamine/acrylic polyol coating formulation using Fourier transform infrared spectroscopy / Dana Garcia in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 908 (09/2000)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 908 (09/2000) . - p. 89-93 Titre : Evaluation of alkane sulfonic acid catalysts and derivatives for curing activity in a melamine/acrylic polyol coating formulation using Fourier transform infrared spectroscopy Type de document : texte imprimé Auteurs : Dana Garcia, Auteur ; Stanley I. Sandler, Auteur ; Joseph Brennan, Auteur ; Olivier Bousquet, Auteur Année de publication : 2000 Article en page(s) : p. 89-93 Note générale : Bibliogr. Langues : Américain (ame) Tags : Matériau  revêtement  Peinture  Mélamine  résine  Acrylique  dérivé  polymère  Durcissement  Réticulation  Acide  alcanesulfonique  Spectrométrie  IR  Transformation  Fourier  Etude  expérimentale Index. décimale : 667.9 Revêtements et enduits Résumé : FTIR measurements may be able to replace more laborious physical property determinations and thus serve as an efficient screening methodology in catalysis driven processes. This possibility was considered in evaluating alkane sulfonic acids catalyst performance to promote the cure of a melamine resin with acrylic polyols. The example chosen here is an evaluation of alkane sulfonic acid derivatives to measure catalytic efficiency of the cure reaction between hexamethoxymethylmelamine (HMMM) and an acrylic polyol. The IR measurements provided information on the extent of reaction, via monitoring the disappearance of the OH stretching mode at 3472 cm-1 associated with the acrylic polyol. This method may also be used to provide detailed information on reaction kinetics and insight into the cure mechanism. As the reaction proceeds, the coating's properties change and IR measurements can serve as a probe for these changes. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5791 [article]

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