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Associative polymer/latex dispersion phase diagrams. II : HASE thickeners / Edward Kostansek in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 2, N° 6 (04/2005)
[article]
Titre : Associative polymer/latex dispersion phase diagrams. II : HASE thickeners Type de document : texte imprimé Auteurs : Edward Kostansek, Auteur Année de publication : 2005 Article en page(s) : p. 417-422 Note générale : Bibliogr. Langues : Américain (ame) Tags : Stabilité colloïdale Polymère associatif Propriété thermodynamique Etude expérimentale Peinture Application Effet concentration Dispersion Groupe hydrophobe latéral Méthacrylate de méthyle copolymère aqueuse Acrylate butyle Epaississant Polyélectrolyte d'éthyle Méthacrylique acide Dimension particule Matériau revêtement Floculation Agent surface Diagramme phase Latex Index. décimale : 667.9 Revêtements et enduits Résumé : The colloidal interactions ofHASE associative polymers and latexes in the presence of surfactant are complicated and subject to a number of variables. Both bridging and depletion flocculation can occur, in addition to good particle dispersion. Dispersion phase diagrams have been developed to help visualize these interactions. The various dispersion states can have a significant effect on coating formulations and film properties. Examples of dispersion phase diagrams are presented for a model HASE anionic associative thickener and various model latexes in the presence of sodium dodecylsulfate and nonionic surfactants. The major variables affecting dispersion behavior are associative polymer concentration, latex particle size, latex surface hydrophobicity, electrolyte concentration, and surfactant concentration. The dispersion phase behavior of the HASE systems is compared to that of HEUR thickened systems reported previously. A significant difference is that much less bridging flocculation is observed in the HASE systems. In addition, nonionic surfactants induced depletion flocculation in the HASE systems but not in the HEUR systems. DOI : 10.1007/BF02733884 En ligne : https://link.springer.com/content/pdf/10.1007%2FBF02733884.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3836
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 2, N° 6 (04/2005) . - p. 417-422[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001483 - Périodique Bibliothèque principale Documentaires Disponible Tailoring HASE rheology through polymer design : Effects of hydrophobe size, acid content, and molecular weight / Wenjun Wu in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 2, N° 6 (04/2005)
[article]
Titre : Tailoring HASE rheology through polymer design : Effects of hydrophobe size, acid content, and molecular weight Type de document : texte imprimé Auteurs : Wenjun Wu, Auteur ; Greg D. Shay, Auteur Année de publication : 2005 Article en page(s) : p. 423-433 Note générale : Bibliogr. Langues : Américain (ame) Tags : Polymère associatif Viscosité cisaillement nul Matériau revêtement Modélisation Propriété rhéologique Etude expérimentale Dispersion aqueuse Peinture Application Solution Relation masse moléculaire propriété Ecoulement cisaillé Modèle composition Latex Epaississant Polyélectrolyte Terpolymère Groupe hydrophobe latéral Méthacrylique acide copolymère Acrylate d'éthyle Index. décimale : 667.9 Revêtements et enduits Résumé : Hydrophobically modified alkali-soluble emulsion (HASE) polymers are an important class of rheology modifiers for waterborne coatings applications. They are typically prepared as terpolymers by emulsion polymerization of ethyl acrylate (EA), methacrylic acid (MAA), and an associative macromonomer. The viscosity development and shear responses of HASE solutions depend on a number of factors. This article presents rheological data reflecting the impacts of three key variables: hydrophobe size, acid content, and molecular weight, on model HASE thickening and rheological performance. The relative contributions of hydrophobic association, chain expansion, and polymer chain length are discussed. In steady shear flow, all thickener solutions approached some constant low-shear viscosity at small deformation rates. At the same molar composition, larger hydrophobe size resulted in higher viscosity development and greater shear thinning behavior. The amount of acid monomer in HASE polymers can influence the balance between hydrophobic attraction and electrostatic repulsion forces. It was found that a minimum of 15 wt% MAA was required to effect dissolution and thickening of the model HASE polymers. Increasing the MAA level yielded higher zero-shear viscosity and storage modulus G' with maximal values being obtained at 40% MAA. The molecular weight of the model thickeners was controlled by the amount of chain transfer agent (CTA) added during polymerization. When the CTA level was below 0.1 wt% based on total monomers, the polymer solutions displayed shear-thinning behavior. A small increase in CTA concentration beyond 0.1% resulted in a dramatic change to Newtonian flow, and the solution viscosity was nearly two orders of magnitude lower. The model thickeners were also tested in a vinyl acrylic architectural paint formulation. The effects of each individual factor on paint thickener efficiency, high-shear, and low-shear properties are discussed and compared with solution rheology for predictive relationships. DOI : 10.1007/BF02733885 En ligne : https://link.springer.com/content/pdf/10.1007%2FBF02733885.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3837
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 2, N° 6 (04/2005) . - p. 423-433[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 001483 - Périodique Bibliothèque principale Documentaires Disponible