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Influence of coating system composition on moisture dynamic performance of coated wood / J. Ekstedt in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 75, N° 938 (03/2003)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 75, N° 938 (03/2003) . - p. 27-37 Titre : Influence of coating system composition on moisture dynamic performance of coated wood Type de document : texte imprimé Auteurs : J. Ekstedt, Auteur Année de publication : 2003 Article en page(s) : p. 27-37 Note générale : Bibliogr. Langues : Américain (ame) Tags : Etude  expérimentale  Corps  gras  végétal  Huile  lin  Liant  Formulation  Acrylique  dérivé  polymère  Alkyde  résine  Absorption  eau  Peinture  émulsion  Perméabilité  Feuil  Propriété  physique  Bois  Utilisation  Matériau  revêtement Index. décimale : 667.9 Revêtements et enduits Résumé : Model coatings with known composition were assessed for liquid water permeability both as single coat systems and combined as primers and topcoats to form regularly used coating systems - in total 38 different systems. The water permeability of the coatings, expressed as water absorption value, was measured by a method similar to the method that now is proposed as a European standard for the assessment of liquid water permeability. During artificial weathering, the samples were measured for a water absorption value, thus showing the change in water permeability as a function of weathering. The study has shown that an excess of surfactants in the alkyd emulsions has a negative effect on the coating's ability to exclude water from the test samples. A waterborne acrylic paint based on a dispersion of larger particle size (0.4 µm) showed a poor ability to exclude water compared to a similar paint based on smaller dispersion particles (0.1 µm). The alkyd emulsion paints, as single coats, showed high water absorption values compared to solventborne paints and acrylic paints. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5594 [article]

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Surfactant behavior and its influence on the viscosity of associative thickeners solutions, thickened latex dispersions, and waterborne latex coatings / David M. Mahli in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 75, N° 938 (03/2003)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 75, N° 938 (03/2003) . - p. 39-51 Titre : Surfactant behavior and its influence on the viscosity of associative thickeners solutions, thickened latex dispersions, and waterborne latex coatings Type de document : texte imprimé Auteurs : David M. Mahli, Auteur ; Mark J. Steffenhagen, Auteur ; Lin-lin Xing, Auteur Année de publication : 2003 Article en page(s) : p. 39-51 Note générale : Bibliogr. Langues : Américain (ame) Tags : Acrylique  dérivé  polymère  Hydrophobisation  Ethylène  oxyde  Agent  surface  Epaississant  Adjuvant  Viscosité  Propriété  rhéologique  Formulation  Peinture  émulsion  eau  Matériau  revêtement Index. décimale : 667.9 Revêtements et enduits Résumé : Surfactants, varying in their chemical composition and hydrophobic behavior, are used in the formulation of a waterborne coating. These differences influence their aggregation in micellar structures, their interaction with associative thickeners, and in particular, the synergies present in their competitive adsorptions on the disperse phases in a waterborne coating. Adsorption of HEUR thickeners on latexes and the ability of surfactants to displace them from those surfaces is an important variable in the dispersion's viscosity. With large particle latexes, viscosity increases arise primarily from the network built through the interaction of HEURs with surfactants in the aqueous phase. Fluorescence is used to verify the mechanism by which surfactants enhance associative thickener viscosities. That is best achieved with nonionic surfactants, because of their synergies with large hydrophobe HEURs at low concentration. With decreasing latex particle size the adsorbed species is an important contributor to the dispersion's viscosity through its contribution to the latex's effective volume fraction increase and when the size of the adsorbed HEUR is matched to the separation distances of the latex at 0.25 volume fraction. Achieving controlled shear-thinning behavior in small particle size latex paints with the economic constraints on the amount of HEUR required to obtain 90 KU viscosities are discussed. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5595 [article]

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Impact of functional group distribution on the adsorption of a polymeric dispersant / Iwao Soga in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 75, N° 938 (03/2003)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 75, N° 938 (03/2003) . - p. 53-58 Titre : Impact of functional group distribution on the adsorption of a polymeric dispersant Type de document : texte imprimé Auteurs : Iwao Soga, Auteur Année de publication : 2003 Article en page(s) : p. 53-58 Note générale : Bibliogr. Langues : Américain (ame) Tags : Polymère  Liant  Groupe  fonctionnel  Pigment  Adsorption  Dispersant  Adjuvant  Peinture  Matériau  revêtement Index. décimale : 667.9 Revêtements et enduits Résumé : Binder polymers functionalized with a small amount of polar groups satisfy both the dispersion quality of paints and the mechanical strength of coating films. For industrial-grade polydisperse dispersant polymers, functional groups are not evenly distributed among the polymer chains. The functional group distribution in polyurethane dispersant polymers was investigated by statistical estimation and an adsorption experiment. The polymeric dispersants had a broad functional group distribution and contained a significant amount of non-functionalized chains. By considering the existence of these ineffective chains, the dispersion behavior of the paint was more clearly explained. The described method can be a useful tool to analyze the structure and the properties of polydisperse functionalized polymers for various applications. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5596 [article]

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Fundamental studies on morphology control for latex systems with application to waterborne coatings : the effect of polymer radical mobility in latex particles during polymerization / Jeffrey M. Stubbs in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 75, N° 938 (03/2003)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 75, N° 938 (03/2003) . - p. 59-67 Titre : Fundamental studies on morphology control for latex systems with application to waterborne coatings : the effect of polymer radical mobility in latex particles during polymerization Type de document : texte imprimé Auteurs : Jeffrey M. Stubbs, Auteur ; Donald Sundberg, Auteur Année de publication : 2003 Article en page(s) : p. 59-67 Note générale : Bibliogr. Langues : Américain (ame) Tags : Transfert  chaîne  Amorceur  Microscopie  électronique  transmission  Liant  Polymérisation  émulsion  Morphologie  Particule  colloïdale  Latex  Peinture  eau  Matériau  revêtement Index. décimale : 667.9 Revêtements et enduits Résumé : This work reports on the development of composite latex particle morphology in seeded, semicontinuous emulsion polymerization. Previous work has explained particle morphology development in terms of the ability of second stage polymer radicals to diffuse into, or penetrate, the seed particles. This article investigates two separate effects that essentially alter the mobility of the second stage polymer radicals. The first is the initiator type, specifically nonionic versus ionic initiators, and the second is the use of chain transfer agent (CTA). It is shown that ionic initiators make it more likely to obtain core shell morphologies by decreasing the penetration of radicals, but only under a narrow set of conditions. Chain transfer agents, on the other hand, allow for more deviation from core shell morphologies by increasing the penetration of radicals, but significant changes were only observed at the highest concentration of CTA studied. Therefore, both factors are fairly subtle and effects are only observed under specific conditions. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5597 [article]

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