[article]
| Titre : |
Polymer diffusion and mechanical properties of films prepared from crosslinked latex particles |
| Type de document : |
texte imprimé |
| Auteurs : |
Patrick Pinenq, Auteur ; Mitchell A. Winnik, Auteur ; Benoit Ernst, Auteur ; Didier Juhué, Auteur |
| Année de publication : |
2000 |
| Article en page(s) : |
p. 45-61 |
| Note générale : |
Bibliogr. |
| Langues : |
Américain (ame) |
| Tags : |
Matériau revêtement Peinture eau émulsion Formation film Latex Réticulation Polymère Diffusion Transfert énergie Propriété mécanique Feuil Résistance traction Etude expérimentale |
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
We have carried out energy transfer (ET) measurements to follow polymer diffusion, as well as oscillatory dynamic mechanical measurements and tensile measurements, on films prepared from structured and unstructured latex particles. All the particles had the same global chemical composition. The base polymer was a copolymer of butyl methacrylate and butyl acrylate with a glass transition temperature (Tg) of 20°C. Structure was introduced in the form of a low level (1 mol%) of crosslinking using seeded semi-continuous emulsion polymerization to control the locus of the crosslinking agent in the particles. Most of the samples were also labeled with donor or acceptor dyes so that ET experiments could be carried out. In this way we could monitor the extent of interdiffusion that occurred in each of the latex films as a function of annealing history. These ET experiments proved to be particularly useful for determining particle morphology for core-crosslinked particles in which only the core was labeled. The linear dynamic mechanical measurements showed that G' and G were sensitive to the particle morphology, with particular sensitivity exhibited by the elastic modulus G'. The tensile properties were less sensitive to particle morphology. Films for tensile experiments were substantially thicker (0.8 mm) than those commonly used for ET studies of polymer diffusion in latex films. Film thickness has no effect on the polymer diffusion rate, but the films for tensile testing were subjected to prolonged drying at 39°C. Under these conditions, sufficient polymer interdiffusion occurs during film formation for the films to acquire substantial strength and toughness, with elongation at break much larger than 100%. Some differences due to morphology are apparent. Films formed from fully crosslinked latex and from core-crosslinked latex with a large core fraction (50 vol%) have somewhat larger tensile strengths, yield strengths, and toughness than those formed from uncrosslinked latex or latex with a small (12 vol%) crosslinked core. These differences become less pronounced when the samples are annealed for long periods of time (100+ hr) at 80°C. |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5816 |
in JOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 72, N° 903 (04/2000) . - p. 45-61
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Polymer diffusion and mechanical properties of films prepared from crosslinked latex particles in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 72, N° 903 (04/2000)
