Spray applications. Part III. Assessment of viscosities at high shear rates and dynamic uniaxial extensional viscosities on fan nozzle air sprayability / Peter T. Elliott in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 4, N° 4 (12/2007)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 4, N° 4 (12/2007) . - p. 341-349 Titre : Spray applications. Part III. Assessment of viscosities at high shear rates and dynamic uniaxial extensional viscosities on fan nozzle air sprayability Type de document : texte imprimé Auteurs : Peter T. Elliott, Auteur ; Mark J. Steffenhagen, Auteur ; J. Edward Glass, Auteur Année de publication : 2008 Article en page(s) : p. 341-349 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Alliages polymères Buse (tuyère) hydroxyéthylcellulose Polyéthylène glycol Polymères hydrosolubles Pulvérisation Revêtements en phase aqueuse:Peinture en phase aqueuse Rhéologie Tension superficielle Viscosité Index. décimale : 667.9 Revêtements et enduits Résumé : The relationship between rheological parameters and the atomization and sprayability of a fluid can be quantified through examination of blends of structurally different water-soluble polymers (W-SPs). This was done previously for roll coatings by blending two high-molecular weight W-SPs: one with segmental rigidity, hydroxyethyl cellulose (HEC), that has a greater impact with increasing concentration on shear viscosities than on extensional viscosities and one with segmental flexibility, poly(oxyethylene) (POE), that exhibits a counter effect. Within these blends the molecular weight of the HEC is varied to increase the viscosities at high shear rates. By blending these two types of W-SPs, two sets of HEC and POE blends (high Mv HEC/high Mv POE and low Mv HEC/ high Mv POE) were prepared exhibiting the same low shear rate viscosity but different viscosities at high shear rates (HSVs). Within each blend set, three ratios of HEC:POE were formulated to have essentially identical shear viscosity profiles, surface tensions, and storage (elastic) moduli (G'), but differences in dynamic uniaxial extensional viscosity (DUEV). This allowed the role of HSVs and DUEVs to be separated in their influence on atomization and sprayability. Within a set, variations in the HEC:POE ratio highlight the dominance of DUEVs as the controlling parameter in the sprayability of a formulation. DOI : 10.1007/s11998-007-9050-z En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-007-9050-z.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3624 [article]

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Spray applications. Part IV. Compositional influences of HEUR thickeners on the spray and velocity profiles of waterborne latex coatings / Peter T. Elliott in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 4, N° 4 (12/2007)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 4, N° 4 (12/2007) . - p. 351-374 Titre : Spray applications. Part IV. Compositional influences of HEUR thickeners on the spray and velocity profiles of waterborne latex coatings Type de document : texte imprimé Auteurs : Peter T. Elliott, Auteur ; J. Edward Glass, Auteur ; David M. Mahli, Auteur Année de publication : 2008 Article en page(s) : p. 351-374 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Atomisation Buse (tuyère) Epaississants Formulation (Génie chimique) Latex Polyuréthane éthoxylé modifié de façon hydrophobe Pulvérisation Revêtements en phase aqueuse:Peinture en phase aqueuse Viscosité Index. décimale : 667.9 Revêtements et enduits Résumé : In this study, the focus is on the spray behavior of latex coatings thickened with structurally different surfactant-modified, water-soluble polymers (associative thickeners of the hydrophobically modified, ethoxylated urethane [HEUR] type). Particle image velocimetry (PIV) profiles are considered in the perspective of the dynamic uniaxial extensional viscosity (DUEV) of the coatings and an effort to understand the results in terms of the structural aspects of the thickener molecules is undertaken. A high-Mv hydroxyethyl cellulose (HEC) thickened formulation, with a significant DUEV, does not atomize well. Among the HEUR thickeners, the addition of larger hydrophobes in the terminal positions requires less thickener to achieve a 90 KU viscosity and produces lower DUEVs and lower viscosities at high-shear rates. This is necessary to produce formulations with acceptable spray characteristics (i.e., good atomization). The sprayability of these systems is reflected in their velocity profiles and particle size/particle size distributions. Poorer spray characteristics are reflected in ligaments and broad particles size distributions. This study highlights the ability to control the particle size/ size distribution and velocity profiles of coatings formulations through the use of structurally different HEUR associative thickeners. Variations in sprayability among different nozzle geometries are also studied. DOI : 10.1007/s11998-007-9051-y En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-007-9051-y.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3625 [article]

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