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Rapid oxidative dehairing using alkaline hydrogen peroxide and potassium cyanate : reuse of the dehairing reagents / William N. Marmer in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 5 (05/2005)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. C, N° 5 (05/2005) . - p. 165-173 Titre : Rapid oxidative dehairing using alkaline hydrogen peroxide and potassium cyanate : reuse of the dehairing reagents Type de document : texte imprimé Auteurs : William N. Marmer, Auteur ; Robert L. Dudley, Auteur Année de publication : 2005 Article en page(s) : p. 165-173 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Studies have continued on rapid dehairing of cattlehide using an oxidative system of alkaline hydrogen peroxide and potassium cyanate. For economic viability, the dehairing mixture needs to be used for more than one dehairing cycle. The number of cycles is dependent upon the residual concentration of the reagents in solution, namely, NaOH, H2O2 and KOCN. The concentrations of these reagents were measured after each dehairing cycle. In addition the solubilized protein concentration and the amount of insoluble material suspended in solution were determined. NaOH, H2O2 and KOCN all decreased with an increase in the number of dehairing cycles. After the 6th or 7th cycle the dehairing times had increased to the point where dehairing still occurred, but was no longer rapid. There was a buildup of, soluble protein in solution as well as suspended (insoluble) material with increasing dehairing cycles. Both the protein and insoluble (mostly hair) material reacted with the dehairing chemicals, resulting in a decrease in the efficacy of the dehairing mixture. Nevertheless, the system appears to offer a viable alternative to sulfide-based rapid dehairing, and further experimentation on a pilot plant scale is merited. En ligne : https://drive.google.com/file/d/1OckTNTPh91tsC3PX1V58kw7OpOUbQZui/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4064 [article]

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An enzymatic beamhouse process coupled with semi-metal tanning and eco-benign post tanning leads to cleaner leather production / Subramani Saravanabhavan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 5 (05/2005)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. C, N° 5 (05/2005) . - p. 174-186 Titre : An enzymatic beamhouse process coupled with semi-metal tanning and eco-benign post tanning leads to cleaner leather production Type de document : texte imprimé Auteurs : Subramani Saravanabhavan, Auteur ; Balachandran Unni Nair, Auteur ; Jonnalagadda Raghava Rao, Auteur ; Palanisamy Thanikaivelan, Auteur Année de publication : 2005 Article en page(s) : p. 174-186 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Leather industry in the world is presently undergoing radical transformation due to environmental pollution and discharge statutes. Hence, the industry is stressed to search for cleaner leather processing. Present leatherprocessing methodologies are known to contribute higher pollution loads. This method of tanning process comprises 'do-undo' logic. In addition, the conventional methods followed in leather processing subject the collagen matrix to wide variation in pH (2.8 - 13.0). This is evidenced from the emission of huge amount of pollution loads such as bio-chemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), total solids (TS), sulfates, chlorides and chromium. In the study illustrated here, the hair and flesh removal as well as fiber opening have been achieved using bio-products at pH 8.0, pickle free semi-metal tanning employing aluminium, vegetable tannins and silica followed by post-tanning using environmental benign chemicals. Hence, eco-benign chemicals have been used throughout the leather processing. It has been observed that the extent of hair removal and opening up of fiber bundles are comparable to that of conventionally processed leathers. This has been demonstrated through scanning electron microscopy (SEM) and softness measurements. The shrinkage temperature of the experimental leathers obtained from this combination tanning system is about 100°C. Performance of the leathers is shown to be on par with conventionally chrome-tanned leathers through physical strength and hand evaluation. The developed process also exhibits significant reduction in BOD, COD, TDS and TS loads by 46, 33, 91, and 92%, respectively. Further, the developed process appears to be economically viable. En ligne : https://drive.google.com/file/d/1C3W77yjX6Y9IzNX6AsVESIapVLntwBAh/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4065 [article]

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Application of power ultrasound in the fatliquoring process / Venkatasubramanian Sivakumar in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 5 (05/2005)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. C, N° 5 (05/2005) . - p. 187-195 Titre : Application of power ultrasound in the fatliquoring process Type de document : texte imprimé Auteurs : Venkatasubramanian Sivakumar, Auteur ; P. G. Rao, Auteur ; G. Swaminathan, Auteur Année de publication : 2005 Article en page(s) : p. 187-195 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Fatliquoring experiments have been carried out with ultrasound under stationary conditions and compared with the process in the absence of ultrasound under stationary as well as dynamic drumming condition. Type of fatliquors such as vegetable, semi synthetic and synthetic fatliquors have been studied. Variation in process parameters like ultrasonic output power, amount of fatliquor, and temperature have also been studied. The results show improvement about 2.5, 1.8, 1.5 times in the fat uptake in leather due to ultrasound for vegetable, semi synthetic and synthetic based fatliquors respectively. The observed order of improvement, vegetable > synthetic fatliquor is in agreement with the hindrance generally expected for fatliquors during penetration as indicated by emulsion particle size and Gel Permeation Chromatography (GPC) data. Therefore, ultrasound is useful for more difficult fatliquoring conditions. The results also indicate that ultrasound under stationary conditions is comparable or better than dynamic drumming conditions. The effects of ultrasound due to pre-sonication and on the viscosity of the fatliquor have also been studied. Leather fiber stricture has been analyzed using Scanning Electron Microscopy (SEM) and found to be more regular and improved by ultrasound aided processing. The studies indicate ultrasound promotes effective emulsification of the fatliquor in water systems rendering better penetration and more uniform distribution through the leather matrix. En ligne : https://drive.google.com/file/d/1m_KAS6enFsf1LaFgGKXa8k_DP2hl_vJy/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4066 [article]

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A comparison of chemical, physical and enzymatic crosslinking of bovine type I collagen fibrils / Andrew Lastowka in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 5 (05/2005)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. C, N° 5 (05/2005) . - p. 196-202 Titre : A comparison of chemical, physical and enzymatic crosslinking of bovine type I collagen fibrils Type de document : texte imprimé Auteurs : Andrew Lastowka, Auteur ; Gennaro J. Maffia, Auteur ; Eleanor M. Brown, Auteur Année de publication : 2005 Article en page(s) : p. 196-202 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Insoluble type I collagen fibrils are used in several biotechnological research applications including artificial organ scaffolding, skin grafts and cell immobilization beads for fluidized bed reactors. In these applications, collagen is usually strengthened against enzymatic degradation and physical stresses by the addition of cross-links. A suitable collagen source for these purposes appears to be bovine corium, from the lower split of a fleshed hide, a by-product of the leather industry. The present study on ball-milled bovine type I collagen examined the documented cross-linking capabilities of glutaraldehyde and dehydrothermal drying with the relatively new enzymatic cross-linking technique involving microbial transglutaminase. To assess the degree of cross-linking by each technique, free amine residues remaining after cross-linking, collagenase resistance and size of cross-linked complexes were determined. Glutaraldehyde cross-linking resulted in the least number of free amines, highest molecular weight aggregates and highest resistance to collagenase degradation. Dehydrothermal drying also produced high molecular weight aggregates, but partially hydrolyzed the protein, making the fibril more susceptible to collagenase. Microbial transglutaminase treated collagen produced large molecular weight aggregates and was more resistant to collagenase degradation than control collagen. This new cross-linking technique warrants additional research attention. En ligne : https://drive.google.com/file/d/1D7vQjt_L_mlKI7riEvxjPUN5GY86B99K/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4067 [article]

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