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Removal of chromium from tanning wastewater by chemical precipitation and electrocoagulation / Bianca Mella in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 100, N° 2 (03-04/2016)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 100, N° 2 (03-04/2016) . - p. 55-61 Titre : Removal of chromium from tanning wastewater by chemical precipitation and electrocoagulation Type de document : texte imprimé Auteurs : Bianca Mella, Auteur ; Ana Cláudia Cristófoli Glanert, Auteur ; Mariliz Gutterres, Auteur Année de publication : 2016 Article en page(s) : p. 55-61 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Eaux usées -- Epuration Electrocoagulation Précipitation (chimie) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Although chromium is used in the form of basic chromium sulfate for processing hides, it has well-known adverse effects when improperly disposed of in the environment under certain circumstances when Cr(III) can be oxidized to Cr(VI). Tanneries use large amounts of water for processing hides ; hence, chromium recovery from tanning wastewater is an environmentally friendly and economically viable alternative, as it can prevent a greater amount of chromium-containing sludge from being disposed of in industrial hazardous waste landfills. Compliance with environmental legislation also poses a challenge to the leather industry, as the parameters for discharging treated wastewater into receiving water bodies are increasingly stringent, which encourages the practice of techniques for recovery and reuse of chemical inputs in the tanning of hides. This study focuses on the removal of the chromium present in tanning wastewater through chemical precipitation and electrocoagulation. In both methods, chromium is separated in the form of an insoluble precipitate either by the addition of alkali or by the oxidation and réduction of metal anodes. Chemical precipitation resulted in 99.74% of removal efficiency, while in electrocoagulation with aluminum, copper and iron efectrodes, removal efficiency was 97.76%, 69.91% and 90.27%, respectively. Note de contenu : - Wastewater sample - Chemical precipitation - Electrocoagulation reactor - Analytical methods En ligne : https://drive.google.com/file/d/1oC6s2fUs82p2BGfS36WAMqlASuQ1TrD2/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26087 [article]

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Effect of hydrophilic chain extenders on properties of hyperbranched waterborne polyurethane / Wang Xuechuan in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 100, N° 2 (03-04/2016)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 100, N° 2 (03-04/2016) . - p. 62-66 Titre : Effect of hydrophilic chain extenders on properties of hyperbranched waterborne polyurethane Type de document : texte imprimé Auteurs : Wang Xuechuan, Auteur ; Ren Jing, Auteur ; Qiang Taotao, Auteur Année de publication : 2016 Article en page(s) : p. 62-66 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Composés organiques -- Synthèse Cuirs et peaux -- Finition Diméthyl butanoïque, Acide Essais de résilience Essais dynamiques Mouillabilité Polymères -- Analyse Polymères -- Propriétés mécaniques Polymères en émulsion Polymères ramifiés Polyuréthanes Propionique diméthylol, Acide Résistance chimique Résistance thermique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Using hydroxyl terminated hyperbranched polymer as the core, dimethylol propionic acid (DMPA), dimethylolbutanoic acid (DMBA), carboxylic acid type monomer (DMCA) as the hydrophilic chain extenders respectively, three different types of hyperbranched waterborne polyurethane leather finishing agents were synthesized. The structures and properties of the products were characterized by FT-IR, SEM, AFM and TG. Simultaneously, the mechanical properties, surface wettability and water and solvent resistance of three films were studied. The results found the order of crystallinity to be : DMBA-HWPU Note de contenu : - EXPERIMENTAL PROCEDURES : Materials - Sources - The synthesis of DMCA - The synthesis of hyperbranched waterborne polyurethane - RESULTS AND DISCUSSION : Fourier transforms infrared spectroscopy - X-ray diffraction - Scanning electron microscopy (SEM) - Atomic force microscope (AFM) - Emulsion particle size - Simultaneous thermal analysis curves - Physical and mechanical properties En ligne : https://drive.google.com/file/d/1GQlPV_HUIq7F-tUUWLvt_sE5TcVb2FzQ/view?usp=drive [...] Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26088 [article]

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Influence of hydrophobic side chain structure on the performance of amphiphilic acrylate copolymers in leather making / Jinxia Du in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 100, N° 2 (03-04/2016)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 100, N° 2 (03-04/2016) . - p. 67-72 Titre : Influence of hydrophobic side chain structure on the performance of amphiphilic acrylate copolymers in leather making Type de document : texte imprimé Auteurs : Jinxia Du, Auteur ; Cai Huang, Auteur ; Biyu Peng, Auteur Année de publication : 2016 Article en page(s) : p. 67-72 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caractérisation Copolymères Cuirs et peaux -- Propriétés mécaniques Douceur (toucher) Etanchéité Polyacrylates Polymères amphiphiles Retannage Tannage au chrome Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A series of amphiphilic copolymers with different hydrophobie side chain structures were prepared through radical copolymerization of acrylic acid and varying hydrophobie acrylate monomers which were then applied to the retanning and fatliquoring processes of chrome-tanned leather. The main properties of the processed leathers were evaluated. The results showed that this kind of copolymer could give to leather, good filling effects, softness, waterproofness and mechanical strength. The application performances of the copolymers in leather-making were obviously affected by the hydrophobie side chain structure, especially the hydrophobie side chain length of copolymers. Compared to copolymers with branched side chains, the copolymers with straight hydrophobie side chains exhibited botter comprehensive performances. Most of the above mentioned properties of the treated leathers were improved significantly with the increase of side chain length. When the length of the hydrophobie side chain was more than C16, they can give leather excellent waterproofness, softness and mechanical strength. The results of dynamic mechanical analysis (DMA) and the scanning electron microscope (SEM) images also showed that the fibre bundles in the leathers were well separated and lubricated by the long hydrophobie side chains. Note de contenu : - EXPERIMENTAL PROCEDURES : Preparation of amphiphilic acrylate copolymers - Characterization of amphiphilic copolymers and the performances of treated lather - RESULTS AND DISCUSSION : Synthesis and characterization of amphiphilic acrylate copolymers - FIlling and fatliquoring properties of amphiphilic polymers - Waterproofness of amphiphilic polymers treated leather - Physical and mechanical properties of amphiphilic polymers treated leather En ligne : https://drive.google.com/file/d/1ZHDIhULrHGSQMd5f8xTbeiYEulSAczUX/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26089 [article]

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Tannin analysis of selected plants from Laikipia County, Kenya / Alex Kuria in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 100, N° 2 (03-04/2016)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 100, N° 2 (03-04/2016) . - p. 73-76 Titre : Tannin analysis of selected plants from Laikipia County, Kenya Type de document : texte imprimé Auteurs : Alex Kuria, Auteur ; Jackson Ombui, Auteur ; Arthur Onyuka, Auteur Année de publication : 2016 Article en page(s) : p. 73-76 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse quantitative (chimie) Chrome Extraction (chimie) pH -- Mesure Poudre de peaux Tanins végétaux Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Due to stringent environmental regulation concerning the disposal of tannery waste products there is continuous research on discovering eco-friendly tanning reagents. Vegetable tannins are less polluting to the environment than chromium. A study has been conducted to evaluate the tannin content and tanning strength of selected vegetable tanning materials found in Laikipia County and their suitability for tanning hides and skins. The hide powder method was used in determining the amounts of tannins. Acacia nilotica, Acacia xanthophinea and Hagenia abyssinica had percentage tannins of 16.8%, 23.8%, 11.73% respectively and all of them had a tanning strength of more than 1.5. Note de contenu : MATERIALS AND METHODS : Collection and preparation of samples - Extraction - Quantitative analysis of tannins - Chromed hide powder preparation - Determination of moisture and total solids - Determination of total soluble solids - Detemination of non-tannins - Determination of tannin content - Determination of pH - Figure : Characteristics of the tested vegetable tanning materials - Table : Results for three trial tannins and mimosa En ligne : https://drive.google.com/file/d/1KPj4oAIuJ8GMKVju0FvUaZgUHHgGS2xX/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26090 [article]

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Moisture sorption isotherms of leather / Naïma Benmakhlouf in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 100, N° 2 (03-04/2016)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 100, N° 2 (03-04/2016) . - p. 77-83 Titre : Moisture sorption isotherms of leather Type de document : texte imprimé Auteurs : Naïma Benmakhlouf, Auteur ; Soufien Azzouz, Auteur ; Hechmi Khedhira, Auteur ; Afif Elcafsi, Auteur Année de publication : 2016 Article en page(s) : p. 77-83 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Teneur en eau Gravimétrie (chimie analytique) Isotherme d'adsorption Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Leather is produced by an industry with high economic and industrial importance and is one of the most expensive products in the world. Owing to its important production, moisture characterization cf leather has become a topic of extended and varied research works. The goal of this work is to determine sorption isotherms of leather as the impact of climate-controlled sorption isotherms of the leather moisture is still not clear, this property is absolutely necessary, especially in regard to leather drying and storage in order to guarantee its quality prior to its industrial use. The sorption isotherms were determined at different levels of temperature 30°C, 40°C, 50°C and 60°C and the equilibrium moisture content of leather samples was measured within the range of 5 to 90% relative humidity, using the static gravimetric method based on saturated salt solutions. The equilibrium water content decreases with increasing temperature. The isotherms are of type Il, according to the classification of Brunauer (1938). Furthermore, the Dent model is found to be the most appropriate for describing the relationship between the equilibrium moisture content, water activity and temperature. En ligne : https://drive.google.com/file/d/1udJlSf7z4WRTa8XwfuO6o0hUGfR8yzyG/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26091 [article]

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Effect of finishing density on the physico-mechanical properties of leather / Sevgi Nalbat in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 100, N° 2 (03-04/2016)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 100, N° 2 (03-04/2016) . - p. 84-89 Titre : Effect of finishing density on the physico-mechanical properties of leather Type de document : texte imprimé Auteurs : Sevgi Nalbat, Auteur ; Ersin Onem, Auteur ; Bahri Basaran, Auteur ; Ali Yorgancioglu, Auteur ; Onur Yilmaz, Auteur Année de publication : 2016 Article en page(s) : p. 84-89 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Aniline Cuirs et peaux -- Finition Cuirs et peaux -- Propriétés mécaniques Déchirure (mécanique) Densité Essais dynamiques Statistique Traction (mécanique) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Finishing is the process in which a polymeric coating is applied in order to improve the appearance and resistance of leather products. The applications at this stage greatly affect the use and appeal of the final products. In this study, the effect of different coating compositions on the physico-mechanical properties of leather was investigated. For this purpose, three different types of finishing formulations including semi-aniline, lightly pigmented and opaque finishes having different covering powers rated from light to heavy, respectively, were applied to the leathers and results were compared with uncoated counterparts. The findings of the study revealed that the application of lightly pigmented finishing statistically increased the tensile strength, single and double edge tear loads, and stitch tear resistance of the leather to a large extent. Semi-aniline and opaque finishing gave lower or, in some cases, statistically insignificant increases in the physico-mechanical properties of the leathers. Note de contenu : - EXPERIMENTAL PROCEDURES : Materials - Application of finishing solutions - Conditioning and sampling of manufactured leathers - Physical tests - Statistical analysis - RESULTS AND DISCUSSIONS : Tensile strength and percentage extension - Single and double edge tear loads - Stitch tear resistance - Extension set En ligne : https://drive.google.com/file/d/16jPINv3-G7hC6KTY0YoHzk4qgPUaS2Kb/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26092 [article]

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The methods and mechanism of unhairing / D. Burton in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 100, N° 2 (03-04/2016)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 100, N° 2 (03-04/2016) . - 12 p. Titre : The methods and mechanism of unhairing Type de document : texte imprimé Auteurs : D. Burton, Auteur Année de publication : 2016 Article en page(s) : 12 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Epilage Laine Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In investigating the efficiencies of unhairing agents it is necessary to ascertain the effects on the old club hairs, the short undergrowth of young hairs, the follicles and the malpighian layer. These structures and the interfibrillary matter, which consists of albumins, globulins and mucoids, are affected by the times which elapse between the death of the animal, flaying and curing as well as by the methods of curing, and soaking. The methods of Ioosening the hair by liquid air, warm water, bacteria, enzymes, alkaIine solutions, alkaline solutions with reducing or oxidising agents, acids and lyotropic salts arc discussed and compared with the methods of tightening the hair with bactéricides, moderato concentrations of caustic soda, acid solutions such as pickles or bran drenches, protein precipitants and increasing or decreasing the moisture content in the case of the woolskins. Microscopie observations show that the unhairing agents all act on the malpighian or soft inner mucous layer. The crux of the unhairing problem is therefore to weaken or partially dissolve the mucous layer of the epidermis and to find a machine which will remove the longer hair and the undergrowth of short young hairs. The soft inner mucous layer is rich in mucoid material. It is still considered that unhairing and bating are in essence the partial removal of this material. In the application of modern scientific researches to the practice of leather manufacture it must be realised that science is dynamic and not static. In any particular field, the scientist has established certain facts and is investigating a number of possibilities. We must be careful to confine our thoughts to the application of established facts and remember the conditions of time, temperature, concentration, movement and degree of aeration which are inherent in these facts. Conclusions for fresh skins do net necessarily apply to salted ones. Again, precision must be used in visualising the processus of leather manufacture. This is by no means as easy as it might appear to die uninitiated for the smallest details are often significant. Note de contenu : THE STRUCTURE AND GROWTH OF THE HAIR AND EPIDERMIS - EXPERIMENTS TO INVESTIGATE THE EFFICIENCY OF VARIOUS UNHAIRING AGENTS : Methods of unhairing - Methods of tightening the hair of wool En ligne : https://drive.google.com/file/d/1lRgGm1yQoC5xouzIahRfqI1uYxdhs5NC/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26093 [article]

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