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The physico-chemical principles of water-based degreasing of animal skins / Gunther R. Pabst in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIX, N° 4 (04/2004)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCIX, N° 4 (04/2004) . - p. 151-156 Titre : The physico-chemical principles of water-based degreasing of animal skins Type de document : texte imprimé Auteurs : Gunther R. Pabst, Auteur ; Sandra Engelskirchen, Auteur ; Thomas Sottmann, Auteur ; Reinhard Strey, Auteur ; Rainer Erhardt, Auteur ; Guenter Oetter, Auteur ; Roland Boehn, Auteur ; Philippe Lamalle, Auteur Année de publication : 2004 Article en page(s) : p. 151-156 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Degreasing of animal skins is an important step in leather making. A huge quantity of surfactants is used for this process, which leads inevitably to environmental problems. The development of eco-friendly degreasing agents and processes is therefore desirable. For a better understanding of this process, the fundamental physico-chemical principles must be investigated. Only after such knowledge of the principles has been obtained is the development of a novel class of eco-friendly degreasing agents feasible. At present, the fundamentals are not well understood. In this paper we present our latest research results on the physico-chemical principles of water-based degreasing. In cooperation with the University of Cologne, we were able to determine that degreasing takes place in two distinct steps. The first step, under the proper conditions, is the formation of a nanophase for solubilizing the grease in the skin. The second step is the conversion of this nanophase into a macroemulsion for transporting the grease out of the skin and subsequently away from it. This knowledge led us to the development of a novel class of degreasing agents in a more eco-friendly degreasing process. En ligne : https://drive.google.com/file/d/1Ekmr152HgFMZ1XVw0qm4LUxqRugXKetu/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4188 [article]

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Role of phenolics in the stabilization of collagen / Balaraman Madhan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIX, N° 4 (04/2004)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCIX, N° 4 (04/2004) . - p. 157-163 Titre : Role of phenolics in the stabilization of collagen Type de document : texte imprimé Auteurs : Balaraman Madhan, Auteur ; T. Ramasami, Auteur ; V. Subramanian, Auteur ; Balachandran Unni Nair, Auteur ; Jonnalagadda Raghava Rao, Auteur Année de publication : 2004 Article en page(s) : p. 157-163 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Stabilization of the fibrous protein collagen is important in biological and industrial processes. In the present study, three representative phenolic compounds - catechol, resorcinol and pyrogallol have been selected to probe their role in the stabilization of collagen. Hydrothermal stability and the stability against enzyme (collagenase) have been considered as the measures for the stabilization process. It has been found that catechol increased the hydrothermal stability of the collagen fibres by 6.5 °C and also the catechol treated collagen fibres exhibited higher resistance against the degradation by enzyme collagenase. Resorcinol treated collagen fibres exhibited least resistance both against heat and collagenase. Pyrogallol increased the shrinkage temperature of the collagen fibres by 4.5 °C and resisted the activity of collagenase to a considerable extent. Molecular modeling studies have provided clear evidence for the significance of electrostatic and hydrogen bonded interaction in the stabilization of collagen by phenolic compounds. En ligne : https://drive.google.com/file/d/1I7oW6yeliem0gIk3ZWh0q9dOZZYYYwuw/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4189 [article]

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Collagen processing / Gennaro J. Maffia in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIX, N° 4 (04/2004)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCIX, N° 4 (04/2004) . - p. 164-169 Titre : Collagen processing Type de document : texte imprimé Auteurs : Gennaro J. Maffia, Auteur ; Eleanor M. Brown, Auteur ; Peter H. Cooke, Auteur ; M. A. Seltzer, Auteur Année de publication : 2004 Article en page(s) : p. 164-169 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Collagen dispersions, produced from fibrils recovered from milled bovine collagen, have shown promise in environmental remediation in applications as settling aids, filtration aids, fractionation media, oil drop stabilizers, and water purification aids. Macroporous structures, processed by controlled lyophilization of collagen dispersions, are suitable as cell culturing substrates. Collagen was structurally characterized during milling to assist in designing a method for scale-up of the production process. In fact, although the initial processing involves a ball mill, the actual operation is more of an unraveling of the fiber to expose the fibrils, which have nanoscale dimensions. During the ball-milling step of production the active surface area of the collagen increases more than 200 times without chemically altering or denaturing the collagen. To demonstrate this throughout the milling process, active surface area per mass, fibril structure, molecular weight distribution, percent lipid, percent nitrogen, and percent ash were monitored. En ligne : https://drive.google.com/file/d/1zuNakelG5Lys4nCDSoLvZepplFoNnqBQ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4190 [article]

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Tanning studies with basic chromium sulfate prepared using chrome shavings as a reductant : A call for 'wealth from waste' approach to the tanning industry / Jonnalagadda Raghava Rao in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIX, N° 4 (04/2004)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCIX, N° 4 (04/2004) . - p. 170-176 Titre : Tanning studies with basic chromium sulfate prepared using chrome shavings as a reductant : A call for 'wealth from waste' approach to the tanning industry Type de document : texte imprimé Auteurs : Jonnalagadda Raghava Rao, Auteur ; Palanisamy Thanikaivelan, Auteur ; Balachandran Unni Nair, Auteur ; Kalarical Janardhanan Sreeram, Auteur Année de publication : 2004 Article en page(s) : p. 170-176 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Leather processing is associated with the generation of both solid and liquid wastes. Various in plant as well as end-of-pipe treatment methodologies are available for the management of liquid wastes. Although several options do exist for handling solid wastes, the presence of chromium causes concern for many of the applications. Chrome shavings contribute to almost 10% of the solid wastes generated from processing raw hides/skins. In this study, chrome shavings have been advantageously used as a reductant for the manufacture of basic chromium sulfate thereby providing a comprehensive closed cycle. Two BCS products developed with chrome shavings alone for reduction (complete replacement of molasses, product A) or partial replacement of molasses (product B) have been employed for tanning of goatskins. Studies reveal that the quality of the wet blue leathers is on par with the leathers tanned with commercial BCS. Shrinkage temperature of the leathers is comparable and is above 100°C at an offer of 1.25% Cr2O3. Chromium exhaustion is in the range of 75 - 80% with 1318 -1490 ppm of chromium in the spent tan liquor. Wet blue leathers tanned with product A possess more fullness among all the leathers, which may be due to the presence of intermediate protein products formed during BCS preparation. This is further confirmed with the scanning electron microscopic analysis. Performance of the crust leathers is comparable to that of conventional tanned leathers in spite of reduction in syntans by 20%. This methodology provides a means for recovering wealth from waste. En ligne : https://drive.google.com/file/d/1_zQqLuBfXl2GkITE1bUD8wEPCMdErPzj/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4191 [article]

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