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A novel formaldehyde-free synthetic chrome tanning agent for pickle-less chrome tanning : comparative study on syntan versus modified basic chromium sulfate / Palanisamy Thanikaivelan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 4 (04/2002)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 4 (04/2002) . - p. 127-136 Titre : A novel formaldehyde-free synthetic chrome tanning agent for pickle-less chrome tanning : comparative study on syntan versus modified basic chromium sulfate Type de document : texte imprimé Auteurs : Palanisamy Thanikaivelan, Auteur ; Balachandran Unni Nair, Auteur ; Jonnalagadda Raghava Rao ; J. Kanthimathi, Auteur Année de publication : 2002 Article en page(s) : p. 127-136 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : An eco-friendly synthetic chrome tanning salt has been prepared through various routes for application at delimed stage viz., conventional preparation using basic chromium sulphate, sulfonated aromatic hydrocarbon, poly carboxylic acid and organic ligands (product 1); in-situ preparation in the manufacture of BCS by introducing the above ingredients excluding pre-made BCS (product 2); in-situ preparation in the manufacture of BCS by introducing the above ingredients excluding pre-made BCS and aromatic hydrocarbon (product 3). A comparative study has been made for their technical aptness, economic viability and environmental friendliness. It has been found that all the products can be used after deliming without the fear of surface deposition. Fullness of the leathers tanned with the products containing aromatic hydrocarbon (AHC) is generally higher than the product without AHC. The scanning electron microscopic (SEM) studies and visual analysis support the above view. The analysis of the identified process streams show that the TS, Cl- and chromium loads are curtailed by 80, 99 and 94%, respectively. The strength and bulk properties of the crust leathers are similar or improved when the integrated product/process is employed. The techno-economic viability study reveals that the chemicals, water, time and power requirements for tanning are reduced by nearly 50% for all the products. However, product 3 tanned leathers need adequate filling during post tanning as conventionally processed. Hence, in spite of its low cost criteria, the use of product 3 is disregarded for tanning skins for fullness-based products. Products 1 and 2 enable the reduction of post tanning syntans by 50% thus reducing the cost of leather production considerably. Especially, product 2 offers a profit oriented pickle-less chrome tanning process. En ligne : https://drive.google.com/file/d/1ULStbIBxaNvxOlLeu1kkvBJaZMHS53Sm/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4310 [article]

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Antiradical efficiency of different vegetable tannin extracts / A. Zalacain in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 4 (04/2002)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 4 (04/2002) . - p. 137-142 Titre : Antiradical efficiency of different vegetable tannin extracts Type de document : texte imprimé Auteurs : A. Zalacain, Auteur ; G. L. Alonso, Auteur ; I. Blazquez, Auteur ; C. Lorenzo, Auteur ; M. Carmona, Auteur Année de publication : 2002 Article en page(s) : p. 137-142 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Vegetable tannin extracts used in the leather manufacture are gained in important due to its antioxidant activity against external agents. In this paper the tannins and related monophenols were evaluated in comparison with market antioxidants using the standard free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH.). Differences observed on its antioxidant activity could be explain in terms of the different structures and molecule conformation, due to the accessibility of the radical DPPH. to the antioxidant centre. The concentration of the extract is important is such property but in this case the vegetable tannin extracts do not have significative differences in the total phenolic composition. The highest antioxidant activity (EC50) was achieved by sumac, followed by tara, chestnut, myrabolans, quebracho and finally mimosa. If the time needed to get to the steady state (TEC50) is taking in account, the mentioned sequence is modified because myrabolan extract react more rapidly than the rest of the extracts leading the antiradical efficiency sequence as myrabolans > sumac > tara > chestnut > quebracho > mimosa. En ligne : https://drive.google.com/file/d/18O0bms2NcjzPkHHF9wUL-LalWqhqMGJt/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4311 [article]

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Application of protein hydrolysate from chrome shavings for polyvinyl alcohol-based biodegradable material / Martina Kresalkova in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 4 (04/2002)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 4 (04/2002) . - p. 143-149 Titre : Application of protein hydrolysate from chrome shavings for polyvinyl alcohol-based biodegradable material Type de document : texte imprimé Auteurs : Martina Kresalkova, Auteur ; Karel Kolomaznik, Auteur ; J. Kupec, Auteur ; L. Hnanickova, Auteur Année de publication : 2002 Article en page(s) : p. 143-149 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The use of hydrolysate from chrome-tanned wastes for producing biodegradable plastics particularly applicable in agriculture requires management of the breakdown of modified compounds of synthetic polymers. In this work, the additive applied for this purpose was protein hydrolysate produced by enzymatic hydrolysis of chrome-tanned shavings. It was used for modifying polyvinyl alcohol which had been processed into water-soluble films often employed in agriculture. This material, after being deposited in soil, undergoes biological degradation (first of all anaerobic) which is supported to a large extent by the addition of protein hydrolysate in particular. For this reason, anaerobic biodegrability tests were performed (volumetric test determining methanogenic activity) and the corresponding percentage of degradation was determined based on a balance of produced biogas and inorganic carbon in the aqueous phase. Polyvinyl alcohol is relatively poorly degradable under aerobic conditions while protein hydrolysate, on the contrary, undergoes biodegradation at a fairly fast rate. From a comparison between the attained degradation degree of blow-extruded film and that of mechanically prepared compounds it follows that the limiting factor of degradability, apart from added protein hydrolysate, is also a chemical reaction between polyvinyl alcohol and hydrolysate taking place during the heat processing of film. It was confirmed that protein hydrolysate from chrome shavings markedly increases biodegradation of material (depending on its content in the plastic matrix), reduces the final cost of product and, last but not least, to some extent also exerts a positive influence on mechanical properties of the film. En ligne : https://drive.google.com/file/d/1DG9POYCMMG1n3uWy8vr5u2otxOhr9-u2/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4312 [article]

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Vigorous proteolysis : reliming in the presence of an alkaline protease and bating (post-liming) with an extremophile protease / S. M. Mozersky in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 4 (04/2002)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 4 (04/2002) . - p. 150-155 Titre : Vigorous proteolysis : reliming in the presence of an alkaline protease and bating (post-liming) with an extremophile protease Type de document : texte imprimé Auteurs : S. M. Mozersky, Auteur ; William N. Marmer, Auteur ; O. Dale Allen, Auteur Année de publication : 2002 Article en page(s) : p. 150-155 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : As part of an investigation into the feasibility of removing from a hide some or all of its decorin while it is being processed into leather, we studied the effects on the physical characteristics of the leather of subjecting the hide to vigorous proteolysis. We used two proteolytic enzyme preparations, one during reliming, and the second for bating post liming. The first is a commercially produced alkaline protease (AP). Extending the work of Alexander in England and of Kronick at Eastern Regional Research Center, ARS, USDA, we found that, for each observed physical property, viz., tensile strength (Smax), Young's modulus (Y), and extensibility (E), the value for the AP-treated samples differed from the corresponding control value by < 6-8% (the least significant difference), thus demonstrating that AP does not adversely affect any of the three physical characteristics. The AP-treated hides are, however, substantially softer and more flexible than the controls. The second protease preparation is one that we made from a halophile selected because it does not produce collagenase. This protease is active in 4M NaCl at a mildly alkaline pH. Bating with the halophile protease in 4M NaCl was found to yield a leather with satisfactory physical characteristics (Smax, Y, and E). High salt concentration will be used experimentally to loosen the tight (albeit non-covalent) bonding of decorin to collagen, thus rendering the proteoglycan more susceptible to proteolysis and removal from the hide. En ligne : https://drive.google.com/file/d/1FkL6j13napjNATdHgURko2lna7B0vxEl/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4313 [article]

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