| Titre : |
Molecular level understanding of the stability difference in collagen induced by chromium sulfate and aluminum sulfate |
| Type de document : |
texte imprimé |
| Auteurs : |
Weimo Han, Auteur ; Jianfei Zhou, Auteur ; Wenhua Zhang, Auteur ; Bi Shi, Auteur |
| Année de publication : |
2017 |
| Article en page(s) : |
p. 273-279 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Collagène -- Stabilité
Sulfate d'aluminium
Sulfate de chrome
Tannage minéralTannage dans lequel interviennent différents minéraux. Le plus répandu est le tannage aux sels de chrome, mais aussi à l’aluminium
|
| Index. décimale : |
675 Technologie du cuir et de la fourrure |
| Résumé : |
Though the tanning process of both chromium(III) and aluminum(III) are mainly the reactions of coordination with the collagen side chain carboxyl groups, the stability toward water and denaturing temperature of Cr(III)-tanned leather is much higher than that of Al(III)-tanned leather. In this paper, the differences between Cr(III) and AI(III) tanning mechanisms are explored from the species distribution of tanning liquors and the thermodynamics of coordination reaction. First, there are more multinuclear metal species in Cr(III) tanning liquor than in Al(III) tanning liquor through visual Minteq. For example, at pH4 Cr3(OH)4(H2O)10 5+ accounted for 39% in 0.05mol/L Cr2(SO4)3, and Al (OH)4(H2O), only 0.04% in 0.05mol/L AI2(SO4)3. In addition, a large amount of negative species Al(SO4)2(H2O)2 (always about 30% in AI2(SO4)3) appeared in Al(III) tanning liquor, which would show low coordinating effect because of the electrostatic repulsion with the ionised collagen sidechain carboxyl groups. The density functional method (DFT) was used to study the kinetics (the electrophilic indexes w) and thermodynamics (the Gibbs energy change ?rG) of tanning reaction with Lanl2dz for metal atoms and 6-31g(d) for non-metal atoms. The results showed that the reactivity of multinuclear species is higher and the complexes formed by collagen and multinucIear species are more stable for both Cr(III) and Al(III), and the differences of ?rG between corresponding Cr(Ill) and Al(lll) tanning reactions are miner. Then the main reason for the lower shrinkage temperature of Al2(SO4)3 may be the lower contents of multinuclear aluminum species and the higher content of the negative specie Al(SO4)2(H2O)2 in AI(III) tanning liquor. These results suggested that appropriate masking agents which could increase the multinuclear aluminum species content and decrease the negative species content should improve the AI(III) tanning process |
| Note de contenu : |
- METHODS : The main chromium and aluminum species present under the pH range of tanning - The models of collagen sidechain carboxyl groups - The theoretical parameters
- RESULTS AND DISCUSSION : The main species in Cr(III) and Al(III) tanning liquor - The reactivity of chromium and aluminium species - The driving force of typical reaction of Cr(III) and Al(III) tanning |
| En ligne : |
https://drive.google.com/file/d/1T7KdyR561R35KhADfXa1mw77cSrGZhXU/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29658 |
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 101, N° 6 (11-12/2017) . - p. 273-279
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Molecular level understanding of the stability difference in collagen induced by chromium sulfate and aluminum sulfate in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 101, N° 6 (11-12/2017)
