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JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) . Vol. XCVIII, N° 10Mention de date : 10/2003Paru le : 15/10/2003 |
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Ajouter le résultat dans votre panierAn approach for the treatment of vegetable tan liquor containing hydrolysable tannins / A. Sharli in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 10 (10/2003)
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Titre : An approach for the treatment of vegetable tan liquor containing hydrolysable tannins Type de document : texte imprimé Auteurs : A. Sharli, Auteur ; Balachandran Unni Nair, Auteur ; Jonnalagadda Raghava Rao, Auteur ; Balaraman Madhan, Auteur Année de publication : 2003 Article en page(s) : p. 381-387 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : In recent times leather industry is looking at options for a tanning system especially based on the natural products such as vegetable tanning materials. Nevertheless there is also a clear shortcoming in the usage of vegetable tanning materials because of the high organic load in the effluent generated, which is difficult to degrade and hence leads to high biological or chemical oxygen demand. Hence, in this study, methods to treat the effluent liquor containing myrobalan, a widely used hydrolysable tannin have been explored to reduce the pollution load generated by the same. Two methods have been adopted for the treatment of the myrobalan liquor. The first method involves breaking down of vegetable tannins to simpler compounds by oxidative degradation using hydrogen peroxide. The second method involves the precipitation of vegetable tannins using zinc sulfate as the precipitant. A 28% reduction in the COD has been obtained for the effluent liquor treated with H2O2 in the presence of Zerolite-Iron catalyst at 50°C. Myrobalan liquor precipitated with zinc sulfate at a pH of 10 has resulted in the reduction of COD by 74%. Additional reduction in the COD has been obtained by adapting the precipitation followed by oxidative degradation method in the presence of Zerolite-Iron catalyst, which has resulted in the reduction of COD load by 96%. En ligne : https://drive.google.com/file/d/1Mo8tKhLCzhOEqy3KmF-imU8IneHay7x8/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4152
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 10 (10/2003) . - p. 381-387[article]Réservation
Réserver ce documentFurther studies on the official methods of analysis for determination of hexavalent chromium level in leather / Dipankar Chauduri in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 10 (10/2003)
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Titre : Further studies on the official methods of analysis for determination of hexavalent chromium level in leather Type de document : texte imprimé Auteurs : Dipankar Chauduri, Auteur ; Ratna Chakraborti, Auteur ; Pinaki Bhattacharya, Auteur Année de publication : 2003 Article en page(s) : p. 388-399 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : This study was carried out primarily to have a better understanding of some of the reported limitations of the official methods of analysis for determining the level of Cr(VI) in leather. In this investigation the stability of Cr(VI) and Cr(III) was tested in several potential extractants and leather extracts. But no redox reactions could be observed in any of the liquors tested. Experiments were also conducted to determine the optimum stirring time for complete extraction of Cr(VI) from leather. The results reveal that a stirring time of 3 hours is insufficient for full chrome leather. In order to determine the kind of change necessary in the extraction procedure to avoid the potential oxidation of Cr(III) during extraction, experiments were also conducted on extraction with phosphate buffer for different time intervals under various pH conditions. The results indicate that more reliable analytical results may be obtained by extracting the sample for 6 hours with phosphate buffer at pH 6.4-6.6. En ligne : https://drive.google.com/file/d/1IcXFPvLBEkR71CdqEFFAAMV953RazfqC/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4153
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 10 (10/2003) . - p. 388-399[article]Réservation
Réserver ce documentApplication of tocopherol to improve the durability of leather / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 10 (10/2003)
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Titre : Application of tocopherol to improve the durability of leather Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Nicholas P. Latona, Auteur Année de publication : 2003 Article en page(s) : p. 400-407 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Durability of leather is a very important quality, particularly the UV and heat resistance for automobile applications. The fast growth in the domestic production of automotive leather to meet the demands of automakers magnifies the significance of this quality. a-Tocopherol (vitamin E) and its derivatives a-tocopheryl succinate and a-tocopheryl acetate are potent free radical scavengers and highly protective agents for collagen fibers against UV damage. Efforts were made to develop a process treatment that produces minimum effluents (i.e., environmentally friendly) and yet significantly increases the UV and heat resistance of a fibrous collagen material: leather. Tocopherol and its derivatives were applied to the grain layer of leather. The treated samples were exposed in a Fadeometer and then evaluated for the efficacy of UV and heat resistance and by Instron testing for mechanical properties (tensile strength and initial strain energy). Observation showed that tocopherol yielded the most promising results compared to its derivatives. Data showed that leather treated with tocopherol resulted in significant improvement in tensile strength and softness and, more importantly, increased strength retention and color fading resistance against UV radiation and heat. En ligne : https://drive.google.com/file/d/1uhz2I5rjk8WEOoPORhm9oPJk7vifMn_j/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4154
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 10 (10/2003) . - p. 400-407[article]Réservation
Réserver ce documentEssential chromium ? / Eleanor M. Brown in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVIII, N° 10 (10/2003)
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Titre : Essential chromium ? Type de document : texte imprimé Auteurs : Eleanor M. Brown, Auteur ; Maryann M. Taylor, Auteur Année de publication : 2003 Article en page(s) : p. 408-414 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : During the production of chrome-tanned leather, chromium is incorporated into the leather with at least three types of interactions. Most important is the chromium that is complexed with collagen to give leather its characteristic properties. Other interactions include nonproductive binding of chromium to collagen and adsorption of chromium by the collagen matrix. To evaluate the extent and possible effects of these other interactions, we extracted chrome shavings with water, HCl, or EDTA to remove adsorbed or loosely bound chromium. The effect of chromium removal on hydrothermal stability was followed by differential scanning calorimetry, and the chromium content of extracts was determined by atomic absorption spectrometry. Extraction of less than 2% of the chromium initially present had no effect on the denaturation temperature, but removal of 3% to 10% of the chromium resulted in a 20°C decrease in the denaturation temperature. As 10% to 60% of the chromium was extracted, the denaturation temperature decreased an additional 30°C, nearly reaching the temperature expected for leather that was not tanned. The results suggest that up to 2% of the chromium is simply adsorbed, and most easily removed. The next 3% to 10% is, however, important for the thermal stability of the shavings. Beyond this level, extraction with EDTA continually shifts the chromium-collagen equilibrium and the denaturation temperature to lower values. The final approximately 40% of the chromium appears to be bound to the collagen, but no longer crosslinked. En ligne : https://drive.google.com/file/d/15VqcpVGPaHzcHsDsf3vEmebpqPLjnN6r/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4163
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVIII, N° 10 (10/2003) . - p. 408-414[article]Réservation
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