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Drying leather with vacuum and toggling sequentially / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVI, N° 3 (03/2011)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CVI, N° 3 (03/2011) . - p. 76-82 Titre : Drying leather with vacuum and toggling sequentially Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Nicholas P. Latona, Auteur ; Joseph Lee, Auteur Année de publication : 2011 Article en page(s) : p. 76-82 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuir -- Séchage Séchage sous vide Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : We investigated a drying method that will enable leather to be dried under vacuum and stretch sequentially to improve area yield. Vacuum drying offers fast speed at a low temperature, which would be advantageous to heat-vulnerable chrome-free leather. Adding a toggle action after vacuum drying could significantly increase area yield. Using a statistical experimental design, we formulated regression models describing how drying variables affect mechanical properties and area yield of chrome-free leather tanned with glutaraldehyde. An effort was also made to estimate the effects of conditioning, staking, and drum milling on the area retention gained by toggle stretching. This study showed that the direction the stretch was applied had a significant effect on the area retention. Results also indicated that conditioning and staking have little effect on area retention, whereas the drum milling caused a significant drop in area retention. Our study also showed under an optimal drying condition, a 12% increase in area yield with good properties can be achieved. Note de contenu : - EXPERIMENTAL : Materials and procedures - Apparatus - Measurements - experimental design. - RESULTS AND DISCUSSION : Area retention - Effects of staking and drum milling - Tensile strength - Elongation - Fracture energy-toughness - Grain break. En ligne : https://drive.google.com/file/d/12Suk1mD0EZVPw2EtKDWDKV_JAi7F4UZu/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11236 [article]

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Use of natural fat emulsions in fatliquoring process and investigation of fatty spue formation / Gökhan Zengin in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVI, N° 3 (03/2011)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CVI, N° 3 (03/2011) . - p. 83-91 Titre : Use of natural fat emulsions in fatliquoring process and investigation of fatty spue formation Type de document : texte imprimé Auteurs : Gökhan Zengin, Auteur ; Altan Afsar, Auteur Année de publication : 2011 Article en page(s) : p. 83-91 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Acides gras Cuirs et peaux -- Dégraissage Cuirs et peaux -- Finition Emulsions Fourier, Spectroscopie infrarouge à transformée de Huiles et graisses Iode Microscopie électronique à balayage Peroxydes Produits de nourriture du cuir Résonance magnétique nucléaire Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Fatty spew is one of the most frequent defects appearing on finished leathers, especially sheepskins. Origins of this problem include an insufficient degreasing process, presence of excess residual natural fat in leather, quantity and quality of fatliquoring material added during the fatliquoring process and defective fatliquoring techniques. It is usually not easy to identify this problem during the processes. The aim of this study is to find out the limit value of natural fat that cause to fatty spew and its effect on leather quality. In the experiments Irish ovine sheepskins were used, as they are known for their high natural fat content. The experiments were carried out in three groups. The first group was processed without degreasing and fatliquoring. The second group was degreased and processed without fatliquoring and the third group was degreased; and fatliquored with 3, 5 and 7% of their own emulsified fat. The application of 3% fat emulsion is agreeable due to fatty spew formation in 5% and 7% fat emulsion application, as expected from preliminary tests. Some physical and chemical characteristics of natural and emulsified fats were investigated such as density, acid, peroxide and iodine values. Visual images of skin surfaces were obtained by Scanning Electron Microscopy (SEM). Gas Chromatography (GC), Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FT-IR). Analyses were performed for the determination of fatty acids components that cause fatty spew defect. It was determined that double bond between C and C in the structure of the palmitoleic and linoleic acids was saturated, the ratio of palmitic and stearic acids was increased and palmitic and stearic acids were found to be the main reasons for fatty spew formation. Note de contenu : METHOD AND RESULTS AND DISCUSSION : Determination of fat content - acid, iodine and peroxide values - Scanning electron microscopy (SEM) - Gas chromatography (GC) analysis - C nuclear magnetic resonance (RMN) - Fourier transform infrared spectroscopy (FTIR) analysis. En ligne : https://drive.google.com/file/d/1S0CFlK1Qi1q2fgvStk1qcPHf4GB-6CyO/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11237 [article]

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Studies on the henna-glutaraldehyde combination tanning system / A. E. Musa in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVI, N° 3 (03/2011)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CVI, N° 3 (03/2011) . - p. 92-101 Titre : Studies on the henna-glutaraldehyde combination tanning system Type de document : texte imprimé Auteurs : A. E. Musa, Auteur ; Rathinam Aravindhan, Auteur ; Swarna Vinodh Kanth, Auteur ; Jonnalagadda Raghava Rao, Auteur ; B. Chandrasekaran, Auteur ; G. A. Gasmelseed, Auteur Année de publication : 2011 Article en page(s) : p. 92-101 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse thermique Cuirs et peaux de chèvres Formulation (Génie chimique) Glutaraldéhyde Henné Microscopie électronique à balayage Tannage combiné Le tannage combiné se dit des tannages qui allient deux familles ou genre de tannage pour obtenir un résultat additionnant les qualités complémentaires des tannins mis en Å“uvre par exemple Chrome-Végétal ou Chrome-Synthétique Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : An organic combination tanning process for the production of upper leathers based on henna and glutaraldehyde was demonstrated in this work. Extract from the leaves of Henna (Lawsonia inermis), widely distributed in Sudan, has been evaluated for its utilization in the combination tanning system based on henna and glutaraldehyde syntan. It was observed that the henna-glutaraldehyde combination tanning system employing 20% Henna extract and 3% Glutaraldehyde syntan provided a shrinkage temperature of 100°C. The Differential Scanning Calorimetric (DSC) data is in accordance with the observed shrinkage temperature. The characteristics of the leathers indicate that the henna-glutaraldehyde combination tanning system provided leathers with good organoleptic properties and comparable strength properties. The leathers were further characterized by chemical analysis and Scanning Electron Microscopy (SEM). The leathers obtained from the combination tanning system were lighter in color compared to control leathers as observed from the color measurement. Thus the possibility of making upper leather using henna-glutaraldehyde combination tanning appears to be promising. Note de contenu : - EXPERIMENTAL : Materials - Aqueous extraction of henna leaves - Henna-glutaraldehyde combination tanning - Visual assessment of the crust leather - Physico chemical analysis of leathers physical testing - chemical analysis - Reflectance measurement - Scanning electron microscopic analysis of leather samples - Differential scanning calorimetry - Analysis of spent liquor. - RESULTS AND DISCUSSION : Organoleptic properties of crust leather for experimental and control - Physical strength characteristics of crust leathers for experimental and control - Analysis of spent liquor - Analysis of henna extract exhaustion - reflectance measurement - Scanning electron microscopic analysis of leather samples - Chemical analysis of the crust leather - Henna and glutaraldehyde combination tanning : an alternative viable tanning option for leather manufacture. En ligne : https://drive.google.com/file/d/1aMNcOU3zFK2qroV7MJjIizlp5WU3-ASO/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11238 [article]

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Ag and Ag/TiO2 nano-dispersed systems for treatment of leathers with strong antifungal properties / Carmen Gaidau in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVI, N° 3 (03/2011)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CVI, N° 3 (03/2011) . - p. 102-109 Titre : Ag and Ag/TiO2 nano-dispersed systems for treatment of leathers with strong antifungal properties Type de document : texte imprimé Auteurs : Carmen Gaidau, Auteur ; Aurora Petica, Auteur ; Teodora Dragomir, Auteur ; Horia Iovu, Auteur ; Corina Andronescu, Auteur Année de publication : 2011 Article en page(s) : p. 102-109 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antifongiques Antimicrobiens Argent Dioxyde de titane Dispersions et suspensions Electrochimie Nanoparticules Spectroscopie de photoélectrons Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The purpose of our work was to create leathers with enhanced antifungal and antimicrobial properties by treating with efficient and ecological agents. Using a simple and productive electrochemical method, stable and high purity nano-Ag based colloidal solutions containing 35 ppm Ag, with 4 nm diameter and – 44 mV zeta potential and Ag/TiO2 dispersed solutions containing 10g/l TiO2 and 45 ppm Ag, with 19.7 nm diameter and – 36.8 mV zeta potential, were obtained. Solutions obtained in this manner have affinity for wet blue or metal-free leather. Even though both colloidal silver solutions and Ag/TiO2 disperse solutions have a very good antifungal and antibacterial activity, only leather treated with Ag/TiO2, especially wet blue type, exhibits a strong antifungal activity up to 28 days of fungi exposure. Also, wet blue and metal-free leathers treated with colloidal silver solutions and Ag/TiO2 dispersed solutions present inhibitory action against Pseudomonas aeruginosa (ATCC 9027) and Staphylococcus aureus (ATCC 6538). XPS measurements, relating to composition and chemical state of the Ag on the leather surface, have shown that leather treated with Ag/TiO2 nano-dispersed systems has a greater content of silver Ag0 than in the case of colloidal silver solutions treatment, Ag being better deposited in the matrix of TiO2 nano-powder, and released gradually as silver ions Ag+. The new products give the perspective of a new range of ecologic products, with applications both in the area of leather articles for medical and everyday use, and in the area of materials for additional treatment of wet blue palletized leathers, etc. Note de contenu : METHODS : Synthesis of CSS and Ag/Tio2 nano-dispersed systems - Analyses of CSS and Ag/TiO2 nano-dispersed systems - Treatment of leathers with CS and Ag/TiO2 nano-dispersed systems - Analyses and leathers treated with CSS and Ag/TiO2 nano-dispersed. RESULTS AND DISCUSSION : Characteristics of CSS and Ag/TiO2 nano-dispersed systems - Antifungal charactristics of Ag and Ag/TiO2 nano-dispersed systems and treated leaters - Bacterial resistance of Ag solutions and Ag/TiO2 nano-dispersed systems and of leathers treated with these solutions - AAS and XPS analyses of silver in treated leathers - Technological and economical consideration of Ag/TiO2 nano-dispersed systems application in leather industry. En ligne : https://drive.google.com/file/d/1f7t3kHpZ9R6YbNLwxYtPbMWLXYi2KFIi/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11239 [article]

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