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Molecular level understanding of the stability difference in collagen induced by chromium sulfate and aluminum sulfate / Weimo Han in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 101, N° 6 (11-12/2017)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 101, N° 6 (11-12/2017) . - p. 273-279 Titre : Molecular level understanding of the stability difference in collagen induced by chromium sulfate and aluminum sulfate Type de document : texte imprimé Auteurs : Weimo Han, Auteur ; Jianfei Zhou, Auteur ; Wenhua Zhang, Auteur ; Bi Shi, Auteur Année de publication : 2017 Article en page(s) : p. 273-279 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Collagène -- Stabilité Sulfate d'aluminium Sulfate de chrome Tannage minéral Tannage dans lequel interviennent différents minéraux. Le plus répandu est le tannage aux sels de chrome, mais aussi à l’aluminium Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Though the tanning process of both chromium(III) and aluminum(III) are mainly the reactions of coordination with the collagen side chain carboxyl groups, the stability toward water and denaturing temperature of Cr(III)-tanned leather is much higher than that of Al(III)-tanned leather. In this paper, the differences between Cr(III) and AI(III) tanning mechanisms are explored from the species distribution of tanning liquors and the thermodynamics of coordination reaction. First, there are more multinuclear metal species in Cr(III) tanning liquor than in Al(III) tanning liquor through visual Minteq. For example, at pH4 Cr3(OH)4(H2O)10 5+ accounted for 39% in 0.05mol/L Cr2(SO4)3, and Al (OH)4(H2O), only 0.04% in 0.05mol/L AI2(SO4)3. In addition, a large amount of negative species Al(SO4)2(H2O)2 (always about 30% in AI2(SO4)3) appeared in Al(III) tanning liquor, which would show low coordinating effect because of the electrostatic repulsion with the ionised collagen sidechain carboxyl groups. The density functional method (DFT) was used to study the kinetics (the electrophilic indexes w) and thermodynamics (the Gibbs energy change ?rG) of tanning reaction with Lanl2dz for metal atoms and 6-31g(d) for non-metal atoms. The results showed that the reactivity of multinuclear species is higher and the complexes formed by collagen and multinucIear species are more stable for both Cr(III) and Al(III), and the differences of ?rG between corresponding Cr(Ill) and Al(lll) tanning reactions are miner. Then the main reason for the lower shrinkage temperature of Al2(SO4)3 may be the lower contents of multinuclear aluminum species and the higher content of the negative specie Al(SO4)2(H2O)2 in AI(III) tanning liquor. These results suggested that appropriate masking agents which could increase the multinuclear aluminum species content and decrease the negative species content should improve the AI(III) tanning process Note de contenu : - METHODS : The main chromium and aluminum species present under the pH range of tanning - The models of collagen sidechain carboxyl groups - The theoretical parameters - RESULTS AND DISCUSSION : The main species in Cr(III) and Al(III) tanning liquor - The reactivity of chromium and aluminium species - The driving force of typical reaction of Cr(III) and Al(III) tanning En ligne : https://drive.google.com/file/d/1T7KdyR561R35KhADfXa1mw77cSrGZhXU/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29658 [article]

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Effect of temperature on moisture-penetrability and breathability of natural leather from microstructure / Zhong Anhua in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 101, N° 6 (11-12/2017)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 101, N° 6 (11-12/2017) . - p. 280-283 Titre : Effect of temperature on moisture-penetrability and breathability of natural leather from microstructure Type de document : texte imprimé Auteurs : Zhong Anhua, Auteur ; Nian Liu, Auteur ; Jiang Xuewei, Auteur ; Xu Wei, Auteur Année de publication : 2017 Article en page(s) : p. 280-283 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Effets de la température Cuirs et peaux -- Propriétés thermomécaniques Humidité Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : This article utilizes the Tinker software to simulate the microspatial structure of type III collagen (1bkv) in natural leather. The four simulation environment temperatures were set at 300K, 320K, 340K, 360K te analyse the relevant trend of variation of coordination number (CN) and interatomic distance (Dis) and the number of interatomic distance (Dis No) of the lbkv collagen whole atom at the different temperatures. The results shows that with the increase of temperature the CN increases tao. As the CN value of 1bkv collagen increased gradually from 125 to 350, the floating frequency of Dis No increases with the increase of simulation time. But 0.5-0.6ns is the inflection lime et simulation. When the temperature increased to 360K, the corresponding Dis No obviously increased while, when the temperature is less than 360K, the change of Dis No is not obvious. This phenomenon shows that temperature is an important factor which affects the Dis No of collagen molecules. The increase of temperature makes the inner spatial structure of collagen molecules become smaller, which explains that, as the temperature rises to a certain value, the naturel leather's moisture-penetrability and breathability decreases. Note de contenu : - The variation tendency of CN of 1bkv collagenmolecules at different temperatures - The change trend of Dis No of 1bkv collagen molecules at the simulation temperature En ligne : https://drive.google.com/file/d/1i7WpvOrKlj6sBwd8SCe_e-YCvjntKbmn/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29659 [article]

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Research on formaldehycle emission characteristics of leather with porous structure by sealed jar method / Yuan Xuzheng in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 101, N° 6 (11-12/2017)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 101, N° 6 (11-12/2017) . - p. 284-289 Titre : Research on formaldehycle emission characteristics of leather with porous structure by sealed jar method Type de document : texte imprimé Auteurs : Yuan Xuzheng, Auteur ; Wang Xuechuan, Auteur ; Lu Weina, Auteur ; Jiang Sujie, Auteur Année de publication : 2017 Article en page(s) : p. 284-289 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chromatographie en phase liquide à hautes performances Cuirs et peaux -- Analyse Cuirs et peaux -- Effets de la température Emission de polluants Formaldéhyde Matériaux poreux Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Formaldehyde release tests of leather with porous structures were carried out according to ISO 17226-3 standard-sealed jar method. Effects of temperature on the release behaviour were investigated. The formaldehyde emission model in sealed system was established according to the law of mass transfer under several reasonable assumptions and verified by the fitting of actual release data. The results showed that formaldehyde emission could be divided into three stages : the linear free release, barrier release and chemical release stages. The linear release .time inversely correlated with mass transfer coefficient of leather. The temperature had a significant promotion impact on release during linear release time. The higher the temperature was, the faster the formaldehyde release. Different types of leather showed different release characteristics because of porosity. The average release speed for sheepskin was faster than that of cowhide at the same temperature. However, with the increase of temperature, the increase in the rate of release speed of cowhide was greater. From 30°C to 60°C, the speed for sheepskin increased 19.39% for every increase of 1 degree Celsius by average, and that of cowhide increased 29.92%. Note de contenu : - EXPERIMENTAL SECTION : Materials - Pretreatment of leather samples - Procedure for the determination of formaldehyde emission by the HPLC method - Determination of porosity of leather by carbon tetrachloride permeation method - SEM observation - Effect of temperature on release behaviour - Release kinetics of leather - RESULTS AND DISCUSSION : Results of the porosity of leather - SEM images of leather cross section - Effect of temperature on formaldehyde emission - Theoretical assumptions of the release model and derivation of release equations - Collection and fitting of actual release data En ligne : https://drive.google.com/file/d/1fKSsaEFWV3nSAOt2XPelqnVLEZ_DWo6I/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29666 [article]

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Some peculiarities of processing leather from short term preserved hide / Kestutis Beleska in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 101, N° 6 (11-12/2017)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 101, N° 6 (11-12/2017) . - p. 290-295 Titre : Some peculiarities of processing leather from short term preserved hide Type de document : texte imprimé Auteurs : Kestutis Beleska, Auteur ; V. Valeikienè, Auteur ; S. Mikulytè, Auteur ; Virgilijus Valeika, Auteur Année de publication : 2017 Article en page(s) : p. 290-295 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Conservation Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Salt curing is a method that is Widely used for the preservation of raw hides/skins worldwide and this load to the enhanced pollution load of tannery by chlorides. The application of alternative short term preservation methods can leed to a Substantial decrease in materials consumption. Unfortunately, the application of new methods of short term preservation has not proceeded due to two main reasons : the complication of the-preposed preservation method used and unfamiliarity with new chemicals. In this study, attempts have been made to show some peculiarities which occur when processing hide subjected to short term preservation by sprinkling with a dry mixture containing 5% NaCl and 1% (salt-less method). Dehydration and rehydration of the short term preserved hides was investigated, and it was established that simple washing for 2 hours is appropriate to rehydrate preserved hide qualltatively end to remove surplus sodium chloride. Short term preserved hide is more susceptible to the action of the unhairing-liming process, and collagen and non-collagen proteins of short term preserved hide are affected more during liming than are proteins of a conventionally salted one. The preservation method has an influence on chromed leather ares yield..Wet-blue leather processed from short term preserved hides has 1.4% higher area yield than that produced from salted hide. The shoe upper leather produced from short term preserved hide contained slightly more chromium and fatliquor but the method of preservation had no influence oh strength and organoleptic properties of the shoe upper leather produced. Note de contenu : - EXPERIMENTAL PROCEDURES : Raw material - Equipment - Chemicals - PARAMETERS OF HIDE PROCESSING - ANALYTICAL METHODS - RESULTS AND DISCUSSION : Dehydration and rehydration of preserved hide - Influence of liming on hide proteins - Influence of preservation method on area yield of wet-blue leather - Industrial trials En ligne : https://drive.google.com/file/d/1ejuSZzwV6W54Zgux22CJz0FGTLEcSQdY/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29667 [article]

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Water hardness as an important parameter of the fatliquoring process / Krzysztof Smiechowski in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 101, N° 6 (11-12/2017)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 101, N° 6 (11-12/2017) . - p. 296-302 Titre : Water hardness as an important parameter of the fatliquoring process Type de document : texte imprimé Auteurs : Krzysztof Smiechowski, Auteur ; Malgorzata Kowalska, Auteur ; Jan Zarlok, Auteur ; M. Lipiec, Auteur Année de publication : 2017 Article en page(s) : p. 296-302 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Analyse Douceur (toucher) Eau dure Emulsions Emulsions -- Stabilité Epaisseur -- Mesure Lixiviation Produits de nourriture du cuir Taille des particules Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The paper presents studies on the influence of selected parameters of water used in fatliquoring. Water of varying hardness (quantifies of calcium, magnesium, iron compounds and of chlorides) was used in the process. Properties of fatliquoring emulsions containing waters of different hardness were determined. It was noted that emulsions were less stable in the presence of eiectrolytes. Generally, the average particle size of prepared fatliquoring emulsions increased if the water phase contained : calcium, magnesium, iron compounds and chlorides. The presented studies on the affects on tanned hides confirmed the desirability of using low hardness water without iron and chlorides. Note de contenu : - Preparation of fatliquoring - Stablity of fatliquoring emulsions - Resistance of fatliquoring emulsions to electrolytes - Determination of fatliquoring emulsion particle size - Dispersion index - Leather fatliquoring process - Determination of fat content in bath after fatliquoring - Determination of fat content in leather - Determination of leather softness according to PH-EN ISO 17235 - Determination of leather sample thickness as per PN-EN ISO 2589 - TABLES : 1. Classification of water for tanning according to BASF - 2. Characteristic of water used to prepare fatliquoring emulsions - Methodology of wet-blue fatliquoring - 4. Stability of 10% emulsion and resistance to electrolytes (Nacl and chromium agent) - 5. Parameters of particle size distribution for fatliquoring emulsions at 20°C and 60°C - 6. Characteristics of the baths after fatliquoring - 7. Thickness and softness of leather samples tested - 8. Free fat content in leather - FIGURES : 1. Particle size distribution of emulsions Em (A)? Et (B), Ebt(C) determined at 20°C - 2. Particle size distribution of emulsions Em (A)? Et (B), Ebt(C) determined at 60°C. The emulsions produced at the two different temperatures (20 and 60°C) with distilled water (free from magnesium, calcium and iron compounds) were observed to have lower average particle sizes. In summary, a greater temperature and increased presence of magnesium, calcium and iron cause the average particle size to increase - 4. Impact of temperature, hardness and presence of iron compounds on average particle size En ligne : https://drive.google.com/file/d/1LJd8IEpiWFxeHGbbtdZ77uC1JTs28BK_/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29668 [article]

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Lack of inhibitory effect of chromium on anaerobic co-digestion of tannery solid wastes / Caroline Borges Agustini in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 101, N° 6 (11-12/2017)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 101, N° 6 (11-12/2017) . - p. 303-307 Titre : Lack of inhibitory effect of chromium on anaerobic co-digestion of tannery solid wastes Type de document : texte imprimé Auteurs : Caroline Borges Agustini, Auteur ; Amanda L. Jasper, Auteur ; Marisa Costa, Auteur ; Mariliz Gutterres, Auteur Année de publication : 2017 Article en page(s) : p. 303-307 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Biogaz Boues d'épuration -- Recyclage Déchets industriels -- Recyclage Digestion anaérobie Recyclage (déchets, etc.) Tannage -- Déchets Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Large amounts of shavings and sludge are generated from wastewater treatment plants of tanneries and are of great concern since their must common destination is their disposal in landfills. ln tanning processes chromium salts are the main tanning agents used. The tannery solid residues characteristics suggest that anaerobic digestion is a potential treatment alternative. Therefore this study aimed to analyze the influence of the presence of chromium in the co-digestion of these two leather industry solid residues of major concern both before and after the tanning stage. The presence of chromium in sludge proved to be more suitable than its absence, producing more biogas — 30.34mI/g of VSS (volatile suspended solids) on average — and a greater reduction of organic load 67.7% on average. This may be due to the low concentration of chromium in essays (up to 15mg/L.) being appropriate for rnany enzymes and co-enzymes in addition to the possible toxicity of the reagents used in the beamhouse process, such as acids and bases, which inhibited the final steps of the anaerobic digestion. The presence of chromium in shavings did not show significant influence probably due to their small proportion in essays. Note de contenu : - Table 1. Essays of 22 factorial design performed in duplicate - Table 2. Chromium concentration in wastes. Waste chromium concentration - Table 3. Final methane percentage by biodigestion essays - Fig. 1 Concentration of chromium in essays before and after biodegradation - Fig. 2. Biogas cumulative generation in the biodegradation essays of mixtures of the tannery wastes : sludge and shavings - Fig. 3. Biological oxygen demand in essays before and after biodegradation En ligne : https://drive.google.com/file/d/19QwjKz4SxPiODVJZesv2Pb8CKONqilE6/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29669 [article]

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Synthesis and performance of nano-encapsulated phase change materials for leather / Chen Jie in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 101, N° 6 (11-12/2017)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 101, N° 6 (11-12/2017) . - p. 308-311 Titre : Synthesis and performance of nano-encapsulated phase change materials for leather Type de document : texte imprimé Auteurs : Chen Jie, Auteur ; Li Xiaoxing, Auteur ; Jia Jizhang, Auteur Année de publication : 2017 Article en page(s) : p. 308-311 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caractérisation Composés organiques Cuir Dioxyde de titane Encapsulation Essais (technologie) Miniémulsions Nanotechnologie Octadécane L'octadécane ou n-octadécane est l'alcane linéaire de formule brute C18H38. C'est aussi le nom générique des isomères de formule C18H38. Polymérisation en émulsion Polystyrène Taille des particules Transition de phase En physique, une transition de phase est une transformation du système étudié provoquée par la variation d'un paramètre extérieur particulier (température, champ magnétique...). Cette transition a lieu lorsque le paramètre atteint une valeur seuil (plancher ou plafond selon le sens de variation). La transformation est un changement des propriétés du système. Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The nano-encapsulated phase change materials for leather with octadecane as core and potystyrene as shell were prepared by mini-emulsion polymerization. Nano-titanium dioxide was added in the preparation. The prepared nano-encapsulated phase change material for leather has good performance which can improve the temperature control and the comfort properties of leather. Note de contenu : - EXPERIMENTAL PROCEDURES : Experimental materials - Experimental methods - Testing and characterization - Application - RESULTS AND DISCUSSION : The chemical structure of the product - The particle size of the product - The phase change latent heat of the product - The effect of the product on leather En ligne : https://drive.google.com/file/d/1RYWZohKMsb7hU7sKxdRew-jEfKjK53Pl/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29670 [article]

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The impact of milling on leather properties and fatliquor distribution / Richard L. Edmonds in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 101, N° 6 (11-12/2017)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 101, N° 6 (11-12/2017) . - p. 312-317 Titre : The impact of milling on leather properties and fatliquor distribution Type de document : texte imprimé Auteurs : Richard L. Edmonds, Auteur ; Adriano Peruzzi, Auteur ; Sue M. Cooper, Auteur Année de publication : 2017 Article en page(s) : p. 312-317 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Croûte (cuir) On entend par "cuir en croûte" des cuirs ayant subi les opérations jusqu'au tannage, à l'exclusion de toute opération de corroyage ou de finissage, mais qui, par opposition aux wet-blue ont été séchés. Cuirs et peaux -- Analyse Cuirs et peaux -- Teneur en matières grasses Douceur (toucher) Echantillonnage Epaisseur -- Mesure Fragmentation Lipides Produits de nourriture du cuir Résistance à la déchirure Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Leather samples were produced With five different types of fatliquor and were treated with a standard milling process. The leathers were assessed before and after milling for strength and softness using standard rnethods and fatliquor distribution was analysed. Milling was pound to increase softness and thickness, and increased the strength of the leather for four of the five different fatliquored samples. The fatliquor distribution was determined using a novel technique where image analysis of a series of photomicrographs of cross sections stained with Sudan III/IV was carried out. It was found that different fatliquors were distributed slightly differently in the leathers. There were peaks of fat in the grain and lower corium with much less in the upper corium. When the fatliquored crust leather was milled the overall distribution of fat through the cross section remained unchanged indicating that changes in physical properties brought about by milling were not the result of bulk fatliquor redistribution. Note de contenu : - MATERIALS AND METHODS : Leather preparation - Physical testing - Staining procedure - Microscope image analysis - RESULTS AND DISCUSSION : Absolute fat content - Tear strength, thickness and softness - Redistribution of fat with mechanical action En ligne : https://drive.google.com/file/d/1d5JimwdFOymORe-NiEQi18bf2LpHzaME/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29671 [article]

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