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Melamine glyoxal resin as a retanning agent - preparation and application / Xie Heng in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 98, N° 1 (01-02/2014)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 98, N° 1 (01-02/2014) . - p. 17-22 Titre : Melamine glyoxal resin as a retanning agent - preparation and application Type de document : texte imprimé Auteurs : Xie Heng, Auteur ; Sun Qingyong, Auteur ; Xuepin Liao, Auteur ; Bi Shi, Auteur Année de publication : 2014 Article en page(s) : p. 17-22 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caractérisation Cuir -- Teneur en formaldéhyde Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés organoleptiques Cuirs et peaux -- Propriétés physiques Formaldéhyde -- Suppression ou remplacement Fourier, Spectroscopie infrarouge à transformée de Mélamine glyoxal Retannage Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Amino resins have played an important role in the manufacture of leather due to their outstanding filling and dyeing properties. However, a traditionally prepared amino resin usually contains free formaldehyde, which is strictly restricted in leather products. With increasing awareness of potential health problems with formaldehyde, there is a growing demand for formaldehyde-free leathers in the global leather market. In this study, a formaldehyde-free amino resin was synthesized by using glyoxal as condensing agent, and its retanning properties were investigated. It was found that the glyoxal can be used to replace formaldehyde to synthesize an amino resin, and the optimal reaction conditions were that the molar ratio of melamine to glyoxal was 1:6, reaction temperature was 333K and reaction time was 3 hours. Retanning experiments with the prepared amino resin indicated that its retanning properties, including fullness, softness, general appearance of the leather and mechanical strength, are better or equal to those that of a traditionally prepared amino resin. Note de contenu : - EXPERIMENTAL PROCEDURE : Materials - Preparation of MG - Characterization of MG - FTIR analysis - APPLICATION PERFORMANCE OF MG : Physical and mechanical tests - Organoleptic properties - Colour differences - Shrinkage temperature determination - Free formaldehyde content in leather - RESULTS AND DISCUSSION : Orthogonal experimental results - FTIR analysis of MG resin - Application experiments of MG (trial 1) - COMPARISON WITH COMMERCIAL AMINO RESIN : Comparison of organoleptic properties - Comparison of physical and mechanical properties - Comparison of chemical indexes of leather and spent liquor - Comparison of dyeing properties En ligne : https://drive.google.com/file/d/1zoUkMI38NeJsf4Tz9PVrvw1r38ou6drW/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21010 [article]

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PH as a parameter for the exponential stability of fatliquor emulsions / Malgorzata Kowalska in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 98, N° 1 (01-02/2014)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 98, N° 1 (01-02/2014) . - p. 23-29 Titre : PH as a parameter for the exponential stability of fatliquor emulsions Type de document : texte imprimé Auteurs : Malgorzata Kowalska, Auteur ; Anna Zbikowska, Auteur Année de publication : 2014 Article en page(s) : p. 23-29 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuir Dispersions et suspensions Emulsions -- Stabilité Lanoline pH Produits de nourriture du cuir Statistique Taille des particules Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The characteristics of emulsions used in a tannery for leather greasing are presented in this study. Emulsions have been prepared from five commercial greasing [fatliquor] products as 10% emulsions which were tested in the pH range from 4 to 8. Mean particle size, fraction number and dispersion coefficients of tested systems are presented. Based on the results obtained it was found that samples with emulsions containing lanolin and samples with emulsions containing mixtures of synthetic and natural oils showed the best stability. Note de contenu : - Materials - Determination of mean particle size and particle distribution of fat emulsions - Determination of dispersion index - Statistical analysis of results En ligne : https://drive.google.com/file/d/1YjOqhCIe78vIBu1opYCE_2ScbOBCqLfo/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21011 [article]

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Effect of neutral salt on pickling and tanning - A study based on assembly behaviour of collagen / Wei Xiangyi in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 98, N° 1 (01-02/2014)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 98, N° 1 (01-02/2014) . - p. 30-34 Titre : Effect of neutral salt on pickling and tanning - A study based on assembly behaviour of collagen Type de document : texte imprimé Auteurs : Wei Xiangyi, Auteur ; Wenhua Zhang, Auteur ; Bi Shi, Auteur Année de publication : 2014 Article en page(s) : p. 30-34 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chlorure de sodium Le chlorure de sodium est un composé chimique de formule NaCl. On l'appelle plus communément sel de table ou de cuisine, ou tout simplement sel dans le langage courant. C'est le principal produit dissous dans l'eau de mer ; on l'appelle alors sel marin. On l'obtient : dans des marais salants par évaporation de l'eau de mer, dans des mines, par extraction du sel gemme (halite) ou en le synthétisant lors de réactions à hautes températures entre du dichlore (Cl2) et du sodium métallique (Na). Le chlorure de sodium est utilisé dans l'industrie chimique pour produire du chlore, de la soude caustique et de l’hydrogène. Décapage 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 : The roles of neutral salt in pickling and tanning processes were investigated by observing the assembly behaviours of collagen in the presences of NaCI and tanning agents. The results indicated that NaCI dehydrated collagen molecules and thus induced collagen to assemble into fibres. This fibre assembly led to the close approach of collagens into fibres and generated wide spaces between collagen fibres. Accordingly, the presence of NaCI could promote the penetration of tanning agents and favour the tanning reaction. Importantly, the dehydration and fibre-forming functions of NaCI resulted in a porous and orderly fibrous microstructure of collagens, which might contribute to the satisfactory mechanical and aesthetic properties of leathers. This underlying action mechanism of NaCI revealed in this research might be useful for us to optimize traditional pickling and tanning techniques and develop practical salt free or low-salt pickling and tanning techniques. Note de contenu : - EXPERIMENTAL METHODS : Preparation of type I collagen - The effect of NaCl concentration on collagen assembly structure observed by AFM - Sample preparation of NaCl-chrome-collagen interaction system - Sample preparation of NaCl- vegetable tannin-collagen interaction system - RESULTS AND DISCUSSIONS : Effect of NaCl concentration on collagen assembly structure - Effect of NaCl on vegetable tannin-collagen interaction En ligne : https://drive.google.com/file/d/1ouBKaUrejM0La9aXTej459CA2lz85zF8/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21016 [article]

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Effect of co-combustion of tannery sludge and coal on the migration of Cr in the bottom ash / Jianfei Zhou in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 98, N° 1 (01-02/2014)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 98, N° 1 (01-02/2014) . - p. 35-41 Titre : Effect of co-combustion of tannery sludge and coal on the migration of Cr in the bottom ash Type de document : texte imprimé Auteurs : Jianfei Zhou, Auteur ; Ya-Nan Wang, Auteur ; Xuepin Liao, Auteur ; Wenhua Zhang, Auteur ; Bi Shi, Auteur Année de publication : 2014 Article en page(s) : p. 35-41 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Boues résiduaires -- Analyse Chrome Combustion Déchets industriels -- Elimination Tannage -- Déchets Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The feasibility of co-combustion of tannery sludge and coal as well as mono-combustion of the sludge was analyzed by tracking the migration of Cr in the sludge and its bottom ash. Most of the Cr was found to be fixed in the bottom ash during combustion when the temperature was not over 600°C. For further analysis of the migration behaviour of Cr after combustion, speciation of Cr in bottom ash was determined by BCR (Community Bureau of Reference) method. It was found that a great deal of Cr was converted from oxidizable fraction in sludge to exchangeable fraction in bottom ash. Moreover, acid leaching test indicated Cr stabilized in the original sludge became easier to leach from the bottom ash. These facts suggest the environmental risk of Cr in the ash is much higher than in the original sludge. Therefore, co-combustion of sludge and coal without any further treatment is not a feasible way to dispose of Cr enriched tannery sludge. Note de contenu : - EXPERIMENTAL PROCEDURES : Materials - Sample preparation - Characteristics of tannery sludge - Co-combustion of tannery sludge and coal - Analytical methods - RESULTS AND DISCUSSION : Characteristics of tannery sludge - Contents of Cr in bottom ashes - Speciation of Cr in bottom ashes En ligne : https://drive.google.com/file/d/1Pjkbk-U_COgMr5D--vf1eALaOW3_ItQE/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21017 [article]

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The role of fungi isolated from historical vegetable-tanned leather on the degradation of peptides and amino acids / Gomaa Abdel-Maksoud in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 98, N° 1 (01-02/2014)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 98, N° 1 (01-02/2014) . - p. 1-7 Titre : The role of fungi isolated from historical vegetable-tanned leather on the degradation of peptides and amino acids Type de document : texte imprimé Auteurs : Gomaa Abdel-Maksoud, Auteur ; Tharwat F. Tadros, Auteur ; Hany Gad, Auteur Année de publication : 2014 Article en page(s) : p. 1-7 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Acides aminés Les acides aminés (ou aminoacides) sont une classe de composés chimiques possédant deux groupes fonctionnels : à la fois un groupe carboxyle –COOH et un groupe amine –NH2. Parmi ceux-ci, les acides α-aminés se définissent par le fait que leur groupe amine est lié à l'atome de carbone adjacent au groupe acide carboxylique (le carbone α), ce qui leur confère la structure générique H2N–CHR–COOH, où R représente la chaîne latérale, qui identifie l'acide α-aminé. Les acides α-aminés jouent un rôle fondamental en biochimie comme constituants élémentaires des protéines : ils polymérisent en formant des liaisons peptidiques qui aboutissent à de longues chaînes macromoléculaires appelées peptides. Alternaria Aspergillus Champignons microscopiques Cuirs et peaux -- Détérioration Hydrolyse enzymatique Pénicilliums Peptides Tannage végétal Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Large numbers of leather artefacts are found in many places in Egypt such as libraries, museums, storehouses, mosques and churches. Many aspects of deterioration especially fungal stains are found on the surface of items such as bookbindings due to unfavourable environmental conditions (such as increased temperature, relative humidity, light, air pollutants etc.). This paper aims to isolate and identify fungi from vegetable-tanned leather bookbindings; study the effect of highly proteolytic fungi in the hydrolysis of leather into peptides and free amino acids, and determination of amino acid content of accelerated aged leather produced using fungi. To achieve this, we isolated and identified fungi from three historical bookbindings. Peptide nitrogen and free amino acids were estimated for up to 90 days of incubation. The effect of microbial ageing of the leather on the amino acid content was also studied. The results revealed that the most frequently found fungi were Aspergillus spp., Penicillium spp. and Alternaria spp. The enzymatic activity of these fungi towards the degradation of gelatin was much higher when a phosphate buffer was used in the media than when a citrate buffer was used. The results are expressed as clear zone (mm). Peptide and free amino acids increased during incubation times of up to 90 days. Hydrolysis plays an important role in the deterioration after infection with the studied fungi. Note de contenu : - MATERIALS AND METHODS : Isolation and identification of fungi - Activating spore species - Preparing spore suspension - Qualitative investigation of fungal proteolytic activity of gelatin - Quantitative estimation of gelatin degradation in culture media by fungal species - The effect of microbial ageing by fungi on the amino acid content of leather - Preparation of the samples for amino acid analysis - RESULTS AND DISCUSSION : Isolation and identification of fungi - Estimation of peptide nitrogen - AMINO ACID ANALYSIS En ligne : https://drive.google.com/file/d/12W28PF1G23A6Aoxicud-QrTtJipdVbFB/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21018 [article]

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A new drying application of garment leather / Sergio Alonso in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 98, N° 1 (01-02/2014)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 98, N° 1 (01-02/2014) . - p. 10-16 Titre : A new drying application of garment leather Type de document : texte imprimé Auteurs : Sergio Alonso, Auteur ; Roberto Zitzumbo, Auteur Année de publication : 2014 Article en page(s) : p. 10-16 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuir -- Séchage Vêtements en cuir Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In the present investigation the effect of two drying alternatives is analyzed on a fine garment leather. Natural hang drying is compared to tumble forced convection drying. The project is of interest due to the extended drying time under a high humidity environment which demands a high inventory of skins and a long overall manufacturing process time. The two drying processes deliver leather pieces of different characteristics, consequently, the physical and subjective properties of the products are compared. The forced convection drying process is set up for the conditions that best maintain the quality of the leather compared to the natural convection drying process. The results show that tumbler drying causes a greater area contraction with respect to natural hanging drying; however, a more pliable leather is obtained, optimal for a garment leather application with suitable elasticity. Both drying alternatives are acceptable when the physical properties are compared, both passing the standards required for a garment leather application. The humidity is also analyzed at the exit of the tumbler drying equipment to obtain a moisture curve that helps to define the moment at which the leather reaches an appropriate humidity so that the drying process can be stopped. Note de contenu : - Moisture reduction - Area loss - Physical properties En ligne : https://drive.google.com/file/d/1iLa533ZOfca3ji6brqjKcF2pmTFxkWzs/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21019 [article]

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