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JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) . Vol. C, N° 9Mention de date : 09/2005Paru le : 24/10/2005 |
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Ajouter le résultat dans votre panierCollagen and polyphenols : new relationship and new outcomes. Part 1. Flavonoid reactions for new tanning processes / Anthony D. Covington in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 9 (09/2005)
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Titre : Collagen and polyphenols : new relationship and new outcomes. Part 1. Flavonoid reactions for new tanning processes Type de document : texte imprimé Auteurs : Anthony D. Covington, Auteur ; L. Song, Auteur ; T. H. Lilley, Auteur Année de publication : 2005 Article en page(s) : p. 325-335 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The process of vegetable tanning is hindered by the astringency of the tannins, which affects the development of their use as organic tanning agents for modern purposes. The use of non tans, either from natural sources such as green tea or by degrading tannins into non tannins, avoids the problem of hindered penetration through pelt due to the high reactivity of the polyphenols. Both tannins and non tannins are capable of engaging in combination tannage with aldehydic agents, to confer high hydrothermal stability to collagen. The use of prodelphinidin or prorobinetinidin polyphenols, characterized by the presence of a pyrogallol B-ring, is preferred in this context. Also, the use of non tannins provides a practical route to modem organic tanning. En ligne : https://drive.google.com/file/d/15iPRhEGaqXGcbGEUN68FWrIxyzBvussz/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4054
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Code-barres Cote Support Localisation Section Disponibilité 003081 - Périodique Bibliothèque principale Documentaires Disponible Collagen and polyphenols : new relationships and new outcomes. Part 2. Phenolic reactions for simultaneous tanning and coloring / Anthony D. Covington in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 9 (09/2005)
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Titre : Collagen and polyphenols : new relationships and new outcomes. Part 2. Phenolic reactions for simultaneous tanning and coloring Type de document : texte imprimé Auteurs : Anthony D. Covington, Auteur ; Ono Suparno, Auteur ; T. H. Lilley, Auteur ; C. S. Evans, Auteur Année de publication : 2005 Article en page(s) : p. 336-343 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Polyphenols are the basic building blocks of natural skin and hair pigments: they can be polymerised to create versions of natural black, brown and orange melanins. These reactions can be catalysed by laccase: not only dothey create colour, but also, if they are conducted in the presence of collagen, the resulting pigment is bound to the leather in a covalent tanning manner. Therefore, the leather becomes coloured by a lightfast pigment, which is firmly fixed. It has not proved possible to create a pure black, but earth shades from green to brown/black are easily produced. It appears to be a feature of this type of stabilising mechanism for collagen, the creation of a polyphenol matrix around the triple helix, that it has the added benefit of actually strengthening the leather. Since every traditional process step effectively weakens collagen, especially tanning, this is the first chemical reaction that has been shown to reverse that effect. En ligne : https://drive.google.com/file/d/1Sex4BZgd7gbc5qBoke0HQi9MOb0bDntG/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4055
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Code-barres Cote Support Localisation Section Disponibilité 003081 - Périodique Bibliothèque principale Documentaires Disponible Thermal utilization of leather scrap after chrome tanning / Witold Taborski in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 9 (09/2005)
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Titre : Thermal utilization of leather scrap after chrome tanning Type de document : texte imprimé Auteurs : Witold Taborski, Auteur ; Zygmunt Kowalski, Auteur ; Zbigniew Wzorek, Auteur ; Michal Konopka, Auteur Année de publication : 2005 Article en page(s) : p. 344-353 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The paper presents the results of studies on physicochemical properties of various kinds of waste leather scraps after chrome tanning with the use of thermal method of their utilization. The heat of combustion of each type of the scraps is not diversified and calculated calorific value is associated with water content. For the investigated mixtures of scraps calorific value was in the range of 9 - 12.5 MJ/kg. That enables to burn them under auto thermal conditions if the average water content does not exceed 50 %. Thermal utilization of leather scraps, alowing to reuse energy from burning the organic matter and to recover chromium, is the advantageous alternative to their storage. The obtained ash (in the amount ~8.5 % of dry mass of processed leather scraps) contains ca. 60 % Cr2O3 and fulfills all the requirements for raw material used in sodium chromate(VI) production. En ligne : https://drive.google.com/file/d/1YVnQ05DTEXfdsrvJ1uQEaTHtLpBBfvBE/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4056
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Code-barres Cote Support Localisation Section Disponibilité 003081 - Périodique Bibliothèque principale Documentaires Disponible Elimination of hexavalent chromium in leather using reducing agents / Chandra Babu Narasimhan Kannan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 9 (09/2005)
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Titre : Elimination of hexavalent chromium in leather using reducing agents Type de document : texte imprimé Auteurs : Chandra Babu Narasimhan Kannan, Auteur ; R. Venba, Auteur ; G. Jothi, Auteur ; B. Ramanaiah, Auteur Année de publication : 2005 Article en page(s) : p. 354-359 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The presence of hexavalent chromium, Cr(VI) in leather and leather products has become a source of concern to the leather industry. Consequently research efforts are being made to identify the source of Cr(VI) and eliminate it in finished leathers. This paper deals with the study on the use of reducing agents based on sulfur and phosphonium compounds for elimination of hexavalent chromium in the leathers. Sodium bisulfite and tetrakis-hydroxymethylphosphonium sulfate were found to eliminate hexavalent chromium well below the detectable limit. The performance of these two compounds has also been studied by the external addition of dichromate in processing. En ligne : https://drive.google.com/file/d/1YfoHwIlwzd-Vdq-P7cHMIOIG_2qZ5fQS/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4057
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Code-barres Cote Support Localisation Section Disponibilité 003081 - Périodique Bibliothèque principale Documentaires Disponible
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Code-barres | Cote | Support | Localisation | Section | Disponibilité |
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003081 | - | Périodique | Bibliothèque principale | Documentaires | Disponible |