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Manipulating chemical reactivity of collagen in tannery processing / David Rabinovitch in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIV, N° 11 (11/2009)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIV, N° 11 (11/2009) . - p. 360-366 Titre : Manipulating chemical reactivity of collagen in tannery processing Type de document : texte imprimé Auteurs : David Rabinovitch, Auteur Année de publication : 2009 Article en page(s) : p. 360-366 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Collagène Cuirs et peaux Réactivité (chimie) Tannage Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The control of the chemical reactivity (astringency) of collagen towards the chemicals used in the tannery is essential not only for controlling their penetration and ultimate fixation, but conforms an effective methodology approach towards achievement of nearer stoichiometric completion of the reactions involved and thus can diminish the needless waste caused by the usual excessive offer of chemicals that is often needed to try and force reactions towards completion because of lack in undertaking appropriate reactivity enhancement in collagen. In the current ecological witch-hunt, only the most efficient tanners will survive. En ligne : https://drive.google.com/file/d/15ZYTA4FKbYWPvMIl-fc40Bhipbv5M6dO/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=6384 [article]

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Influence of retanning of the adsorption capacity of water on cattlehide collagen fibers / Keyong Tang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIV, N° 11 (11/2009)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIV, N° 11 (11/2009) . - p. 367-374 Titre : Influence of retanning of the adsorption capacity of water on cattlehide collagen fibers Type de document : texte imprimé Auteurs : Keyong Tang, Auteur ; Dominick J. Casadonte, Auteur ; Dennis C. Shelly, Auteur ; Jie Liu, Auteur ; Ming Yang, Auteur ; Xuejing Zheng, Auteur Année de publication : 2009 Article en page(s) : p. 367-374 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Adsorption Collagène Cuirs et peaux Tannage Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : There are an abundance of hydrophilic groups in the collagen fibers in leathers. Because the affinity between these hydrophilic groups and water molecules varies with changes in temperature and relative humidity, leathers will adsorb or de-adsorb water as these factors change; affecting strength, permeability, and thermal stability. Retanning is a key operation in leather making with the purpose of retanning is to obtain leathers with some special characteristics. The water content in leathers, often 15-20 wt%, is an amount that cannot be neglected. However, few reports are found on the interactions between collagen and water, particularly the influence of retanning on the interaction between water and collagen fibers. The state that water molecules exist in collagen fibers, the mechanism for collagen fibers to adsorb water, the de-adsorption kinetics for water molecules to escape from collagen fibers, and the influence of retanning on the adsorption of water on collagen fibers need to be studied to improve the leathermaking technology for controlling the structure and behaviors of leathers. In this study, after being chrome tanned, collagen fibers were retanned with chrome, glutaraldehyde, TGR retanning agent (proprietary acrylic based), and wattle extract, respectively, to obtain different retanned samples. The water adsorption isotherms of the samples were determined by using a gravimetric method, by which the influence of retanning on the equilibrium water adsorption capacity and the influencing mechanism were evaluated. Different retanned samples varied in water adsorption characterization and equilibrium adsorption capacity. The TGR retanning increased the equilibrium adsorption capacity, while glutaraldehyde retanning decreased it; likely related to differences in retanning mechanisms. For different relative humidity environments, leathers should be retanned with different retanning agents to get an optimum property. Based on the adsorption characterization and the equilibrium adsorption capacity for the samples, different mathematics models were used to describe the adsorption process and the adsorption mechanism. Six models were chosen to fit the experimental data, and it was found that the Bradley model was the best to describe the adsorption. En ligne : https://drive.google.com/file/d/1Rv1WvrffcvoLu3ITj9Od-y-F5wT4O2l2/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=6385 [article]

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Ultrasound assisted enhancement in wattle bark (Acacia Mollissima) vegetable tanning extraction for leather processing / Venkatasubramanian Sivakumar in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIV, N° 11 (11/2009)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIV, N° 11 (11/2009) Titre : Ultrasound assisted enhancement in wattle bark (Acacia Mollissima) vegetable tanning extraction for leather processing Type de document : texte imprimé Auteurs : Venkatasubramanian Sivakumar, Auteur ; G. Swaminathan ; P. Srinandini ; V. Shriram ; J. Jayapriya, Auteur Année de publication : 2009 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuirs et peaux Tannage Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : This paper analyzes the effect of ultrasound on a batch wattle bark tannin extraction process. Extraction from wattle bark presents a unique case of a two-component system in the form of condensed tannins and non-tannins. Hence, quantitative analysis of tannin content in the extract by spectrophotometery as well as total extracts analysis has been performed. The influence of various process parameters such as ultrasonic power, time, agitation and temperature on extraction has been studied. The results show significant 2-3 and 1.2-1.7 fold improvement respectively for total extract and tannin content due to the use of ultrasound 40-120 W as compared to control at 30°C suggesting mass transfer enhancement in leaching of strongly bound tannins from wattle bark due to ultrasound. The results indicate total extract and tannins obtained in ultrasonic process (80 W), devoid of external heating is better than control at 30°C. Better total extraction and comparable tannin content obtained using ultrasound, 120 W when compared to control at 60°C. Efficacy of tannin extract has been analyzed which indicates significant improvement in rate of tannin uptake for ultrasonic extract as compared to control extract by the bovine pelt. Therefore, the present study clearly indicates use of ultrasond in wattle tannin extraction is a viable enhancement with added advantages even dispensing with external heating. En ligne : https://drive.google.com/file/d/1SVkD-hx9VgcIZye6wptdeVMBzrgq1YDQ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=6386 [article]

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Electro-oxidation of saline wastewater from tannery and reuse of recovered salt / P. Vijayalakshmi in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIV, N° 11 (11/2009)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIV, N° 11 (11/2009) . - p. 384-391 Titre : Electro-oxidation of saline wastewater from tannery and reuse of recovered salt Type de document : texte imprimé Auteurs : P. Vijayalakshmi, Auteur ; P. Saravanan, Auteur ; Raghavan Chandrasekar, Auteur ; S. Sundarapandiyan, Auteur ; G. Rajeswari, Auteur Année de publication : 2009 Article en page(s) : p. 384-391 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuirs et peaux Tannage Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The objective of this work is to treat the saline wastewater from tanneries to recover salt and to study the reuse of the recovered salt. Soak liquor from the tannery was treated electrochemically using graphite electrodes. The reduction in TKN, protein and COD was 78.52%, 83.02% and 79.35% respectively and complete disinfection was also achieved. The treated soak liquor was evaporated by solar evaporation and the salt recovered used for curing of skins. Curing efficacy was assessed for a period of 32 days. The preservation efficacy of the recovered salt, in terms of moisture and bacterial population of the hides, was found to be on par with that of the hides preserved using fresh salt. Soaking wastewater of volume 1 m3 was also treated on a commercial scale. Three batches of treatment were carried out. The salt recovered was reused for preservation of raw hides. The quality of the preserved hides and the wet blue leathers were also assessed. Results of the commercial scale experiments were similar to the results of the laboratory scale experiments. Cost of treatment was about 0.68 US $ per m3. Electrochemical treatment of soak liquor was found to be effective in pollution attenuation. En ligne : https://drive.google.com/file/d/1LbcsXqF216V1kkUgVsAYzqfDFq8vjq6H/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=6387 [article]

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