[article]
| Titre : |
Synthesis and characterization of ambient-temperature self-crosslinked waterborne polyurethanes with a novel diol chain extender bearing two ketone groups |
| Type de document : |
texte imprimé |
| Auteurs : |
Mali Liao, Auteur ; Dongcheng Sun, Auteur |
| Année de publication : |
2016 |
| Article en page(s) : |
p. 667-676 |
| Note générale : |
Bibliogr. |
| Langues : |
Américain (ame) |
| Catégories : |
Auto-réticulation
Cétones
HydrazineL’hydrazine, de nom officiel diazane, de formule chimique N2H4 et de formule semi-développée H2N-NH2, est un composé chimique liquide incolore, avec une odeur rappelant celle de l’ammoniac. Elle est miscible à l'eau en toutes proportions.
Les hydrazines constituent également une famille de composés chimiques dérivés de l'hydrazine (H2N-NH2 par substitution d'un ou plus atomes H par des radicaux hydrocarbonés (par exemple la 2,4-dinitrophénylhydrazine).
La structure de l'hydrazine se présente sous l’aspect de deux molécules d’ammoniac accouplées l’une à l’autre par enlèvement d'un hydrogène pour chacune des deux molécules. Chaque sous-unité -NH2 se présente sous une forme pyramidale.
Polymères en émulsion
Polyuréthanes
Réactions chimiques
|
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
A series of ambient-temperature self-crosslinked waterborne polyurethanes denoted as WBPUs were successfully synthesized by incorporating a novel diol chain extender bearing two ketone groups, 2,2-bis(4-(2-hydroxypropoxy levulinate)phenyl)-propane (BHLPP), which was prepared using 2,2-bis(4-(2,3-epoxypropoxy)phenyl)-propane and levulinic acid, with 4,4-methylenedicyclohexyl diisocyanate, poly-neopentylene adipate glycol, and dimethylolpropionic acid. After post-adding adipic dihydrazide (ADH), self-crosslinking was achieved by the reaction between the ketone (–CO–) of BHLPP and the hydrazine (–NHNH2) of ADH during film formation. For comparison, noncrosslinked waterborne polyurethane (WPU) without BHLPP and ADH was prepared. The structure of BHLPP was characterized by IR and NMR. The properties of the WPU and WBPU dispersions were investigated by measuring the stability, particle size, and morphology. The effects of the ratio of n(–NHNH2)/n(–CO–) and the content of BHLPP were studied in terms of hardness, water resistance, solvent resistance, and thermal properties of WPU and WBPU films. The WBPU dispersions exhibited excellent stability, bimodal distribution, and regular spheroid morphology. The optimal ratio of n(–NHNH2)/n(–CO–) for ketone–hydrazine self-crosslinking was 0.75:1. Importantly, the WBPU films showed superior hardness, water resistance, solvent resistance, and thermal properties to WPU film. |
| Note de contenu : |
- EXPERIMENTAL : Materials - 2,2-Bis(4-(2-hydroxypropoxy levulinate) phenyl)-propane (BHLPP) synthesis - BHLPP separation and purification - WBPU and WPU synthesis - Neutralization of the prepolymer - Dispersion formation - Measurements
- RESULTS AND DISCUSSION : Characterization of BHLPP - 1H and 13C NMR of BHLPP - Stability, particle size, and morphology of WPU and WBPU dispersions - Determination of the ratio of n(-NHNH2)/n(-CO-) for ketone-hydrazine self-crosslinking - Hardness, water and solvent resistance of the WPU and WBPU films - Thermal property of WPU and WBPU films |
| DOI : |
10.1007/s11998-015-9773-1 |
| En ligne : |
https://link.springer.com/content/pdf/10.1007%2Fs11998-015-9773-1.pdf |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26747 |
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 13, N° 4 (07/2016) . - p. 667-676
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Synthesis and characterization of ambient-temperature self-crosslinked waterborne polyurethanes with a novel diol chain extender bearing two ketone groups in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 13, N° 4 (07/2016)
