[article]
| Titre : |
Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM |
| Type de document : |
texte imprimé |
| Auteurs : |
Cheng-Le Zhao, Auteur ; L. E. Scriven, Auteur ; H. Ted Davis, Auteur ; Haiyan Ge, Auteur ; Alan Smith, Auteur ; Shane J. Stafslien, Auteur |
| Année de publication : |
2006 |
| Article en page(s) : |
p. 109-115 |
| Note générale : |
Bibliogr. |
| Langues : |
Américain (ame) |
| Catégories : |
Colloides
Composés organiques volatils
Copolymères greffés
Floculation
Latex
Microscopie électronique à balayage
Morphologie (matériaux)
Oxyde d'éthylèneL'oxyde d'éthylène, ou 1,2-époxyéthane, oxyde de diméthylène, oxacyclopropane, ou encore oxirane est un composé organique, le plus simple de la classe des époxydes. Il est important pour l'industrie chimique, entre autres dans la production d'éthylène glycol, ainsi que dans les industries pharmaceutique et agroalimentaire.
Polyacryliques
Polyméthacrylate de butyle
Revêtements en bâtiment:Peinture en bâtiment
Revêtements en phase aqueuse:Peinture en phase aqueuse
Stabilité thermique
|
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. |
| DOI : |
10.1007/s11998-006-0013-6 |
| En ligne : |
https://link.springer.com/content/pdf/10.1007%2Fs11998-006-0013-6.pdf |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3701 |
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 3, N° 2 (04/2006) . - p. 109-115
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Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 3, N° 2 (04/2006)
