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Tannic acid-phosphonium combination : A versatile chrome-free organic tanning / N. N. Fathima in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CI, N° 5 (05/2006)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CI, N° 5 (05/2006) . - p. 161-168 Titre : Tannic acid-phosphonium combination : A versatile chrome-free organic tanning Type de document : texte imprimé Auteurs : N. N. Fathima, Auteur ; Rathinam Aravindhan, Auteur ; Jonnalagadda Raghava Rao, Auteur ; Balachandran Unni Nair, Auteur Année de publication : 2006 Article en page(s) : p. 161-168 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : An organic combination tanning system based on tannic acid, a precursor to vegetable tannins and tetrakis (hydroxymethyl) phosphonium sulfate (THPS) as a substitute for chrome tanning has been developed. The shrinkage temperature of the leathers obtained is 88°C. The tanning system is versatile in terms of processing both upper and garment leathers. The physical strength characteristics and organoleptic properties of the leathers obtained are comparable to that of chrome tanned leather. Environmental impact assessment shows that there is reduction in total solids when compared to chrome tanning. En ligne : https://drive.google.com/file/d/1v82nWni65vFi65DJoGNZdJVFB21E5g6o/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4010 [article]

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Use of enzymatically modified gelatin and casein as fillers in leather processing ! / Maryann M. Taylor in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CI, N° 5 (05/2006)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CI, N° 5 (05/2006) . - p. 169-178 Titre : Use of enzymatically modified gelatin and casein as fillers in leather processing ! Type de document : texte imprimé Auteurs : Maryann M. Taylor, Auteur ; Eleanor M. Brown, Auteur ; William N. Marmer, Auteur ; Lorelei P. Bumanlag, Auteur Année de publication : 2006 Article en page(s) : p. 169-178 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Prior research from this laboratory demonstrated that chemically modified collagen byproducts could be used effectively as fillers during leather processing. The gelatins were reacted with glutaraldehyde and, after application to veiny leather, these highly polymerized gelatins did fill and more importantly were bound to the substrate. The applications were followed by using fluorescently labeled gelatin that was added to a stock solution and the final products were examined under a microscope that had the capability of showing that the gelatins fluoresce. In this present study, fluorescently labeled gelatins were polymerized by using microbial transglutaminase as the cross-linking agent and the reactions took place in either the leather itself or the samples were first prepared and then added to the leather. Furthermore, we wanted to see, based on results from our earlier experiments in which we produced biopolymers from enzyme-modified gelatin and casein, if these products could also be effective fillers. In these experiments, we labeled casein as well as the gelatin. Varying conditions were examined for optimal filling results. The results showed that indeed these enzymatically prepared products could be used effectively as fillers and moreover were bound to the leather and would not easily be removed during further processing. En ligne : https://drive.google.com/file/d/1bXAsNyNnq9yMRcAF5q_RaKQl_8W3yNTr/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4011 [article]

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Computer modelling of a type-1 collagen fibril in water. 1. model development and validation / Lorenz Siggel in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CI, N° 5 (05/2006)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CI, N° 5 (05/2006) . - p. 179-191 Titre : Computer modelling of a type-1 collagen fibril in water. 1. model development and validation Type de document : texte imprimé Auteurs : Lorenz Siggel, Auteur ; Ferenc Molnar, Auteur Année de publication : 2006 Article en page(s) : p. 179-191 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Type-1 collagen is the principle component of hides used to produce leather. The amino acid sequence for calf skin type-1 collagen is known, as well as the macroscopic structure as seen in electron micrographs. However, little is known about the intermediate scale or atomistic level. With our work we have established a state-of-the-art molecular model of a collagen fibril that is large enough to mimic parts of the fibrilar system and provide molecular level detail about the changes in structure and properties due to varying pH or the effect of leather chemicals and dyes. This paper covers the construction and validation of the varying models which evolved in the course of the work. The density and swelling behavior as a function of pH, as well as "pickling" with 12% NaCl was qualitatively reproduced. In both experiment and our simulation, swelling occurs at very high and low pH, but not in the neutral system or the acidic system when 12% NaCl is first added ("pickling"). The mobility of water in the systems of varying pH was studied and show that water is surprisingly mobile in the fibril when compared to diffusion in the bulk. The interaction of side chains in collagen with one another at the differing pH's encountered during tanning was also examined. En ligne : https://drive.google.com/file/d/1RFManXFOvhsibQKvpcACdFhMc0tae4sj/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4012 [article]

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A new leather-making process for meeting eco-label standards : Processing of goatkins / Subramani Saravanabhavan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CI, N° 5 (05/2006)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CI, N° 5 (05/2006) . - p. 192-205 Titre : A new leather-making process for meeting eco-label standards : Processing of goatkins Type de document : texte imprimé Auteurs : Subramani Saravanabhavan, Auteur ; B. Chandrasekaran, Auteur ; Palanisamy Thanikaivelan, Auteur ; Balachandran Unni Nair, Auteur ; Jonnalagadda Raghava Rao, Auteur Année de publication : 2006 Article en page(s) : p. 192-205 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Eco-labels are used to guarantee the consumer a product meets certain minimum standards relating to its environmental impact during production, use or disposal, and to distinguish the product from competitors in a positive way. The leather industry, especially in developing countries, has provided economic benefits but suffers from a negative image due to the environmental impact pf tannery wastewaters, solid wastes and gas emissions. The conventional method of tanning involves a 'do-undo' process and subjects the skin or hide to wide variations in pH (2.8 - 13.0). This results in the emission of significant pollution loads, such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), total solids (TS), sulfates, chlorides and chromium. In the approach demonstrated here, hair and flesh removal, as well as fiber opening, have been achieved using biocatalysts at pH 8.0; tanning using optimized pickle and basification-free chrome tanning followed by post-tanning using environmental benign chemicals. It has been found that the extent of hair removal and opening up of fiber bundles are comparable to that of control leathers. This has been substantiated through scanning electron microscopic (SEM) analysis and softness measurements. Performance of the leathers is shown to be on par with control chrome-tanned leathers through physical and hand evaluation. The shrinkage temperature of the leathers obtained from this optimized pickle and basification-free chrome tanning system is above 120°C. The process also exhibits significant reduction in BOD, COD, TDS and TS loads by 90, 92, 89 and 90%, respectively. Processed leathers satisfy the key parameters of both the Indian eco-mark standard and the German eco-label standards (Oko-Tex, SG (Schadstoff Gepruffl), LGR (Lederinstitut Gerberschule Reutlingen)). Finally, the developed process seems to be economically viable. En ligne : https://drive.google.com/file/d/1l8FviqEK27Dlu4ePtejFM4mzqk0JIDKl/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4013 [article]

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