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JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) . Vol. CXII, N° 11Mention de date : 11/2017Paru le : 10/11/2017 |
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Ajouter le résultat dans votre panierThermodynamic investigations on chrome and aluminum tanning / Li Wang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXII, N° 11 (11/2017)
[article]
Titre : Thermodynamic investigations on chrome and aluminum tanning Type de document : texte imprimé Auteurs : Li Wang, Auteur ; Wei-Mo Han, Auteur ; Yue Yu, Auteur ; Jian-Fei Zhou, Auteur ; Wen-Hua Zhang, Auteur ; Bi Shi, Auteur Année de publication : 2017 Article en page(s) : p. 360-366 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Adsorption
AluminiumL'aluminium est un élément chimique, de symbole Al et de numéro atomique 13. C’est un métal pauvre, malléable, de couleur argent, qui est remarquable pour sa résistance à l’oxydation13 et sa faible densité. C'est le métal le plus abondant de l'écorce terrestre et le troisième élément le plus abondant après l'oxygène et le silicium ; il représente en moyenne 8 % de la masse des matériaux de la surface solide de notre planète. L'aluminium est trop réactif pour exister à l'état natif dans le milieu naturel : on le trouve au contraire sous forme combinée dans plus de 270 minéraux différents, son minerai principal étant la bauxite, où il est présent sous forme d’oxyde hydraté dont on extrait l’alumine. Il peut aussi être extrait de la néphéline, de la leucite, de la sillimanite, de l'andalousite et de la muscovite.
L'aluminium métallique est très oxydable, mais est immédiatement passivé par une fine couche d'alumine Al2O3 imperméable de quelques micromètres d'épaisseur qui protège la masse métallique de la corrosion. On parle de protection cinétique, par opposition à une protection thermodynamique, car l’aluminium reste en tout état de cause très sensible à l'oxydation. Cette résistance à la corrosion et sa remarquable légèreté en ont fait un matériau très utilisé industriellement.
L'aluminium est un produit industriel important, sous forme pure ou alliée, notamment dans l'aéronautique, les transports et la construction. Sa nature réactive en fait également un catalyseur et un additif dans l'industrie chimique ; il est ainsi utilisé pour accroître la puissance explosive du nitrate d'ammonium.
Chrome
Poudre de peaux
Tannage minéralTannage dans lequel interviennent différents minéraux. Le plus répandu est le tannage aux sels de chrome, mais aussi à l’aluminium
ThermodynamiqueIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Chromium(III) and aluminum(III) have some history of use in the leather industry, and the leathers tanned by them are greatly different in hydrothermal stability. However, the direct measure of thermodynamic characteristics of the tanning process is difficult due to the binary fibers/solution system. In this paper, the thermodynamics of chrome/aluminum tanning reaction was obtained by means of adsorption thermodynamics. The hide powder was used to investigate the adsorption behavior of both Cr(III) and Al(III), and the surface electrochemical property of hide powder was characterized by Zeta potential analyzer. The results showed that the adsorption isotherm of both Cr(III) and Al(III) could be well described by the Langmuir equation, and the quantity of Cr(III) absorbed at pH 4 is similar to that of Al(III) at pH 3.5 using the dimension of mol/g collagen fibers. Then the dimensionless equilibrium constants of such binary fibers/solution systems were obtained. The data of Gibbs free energy change (?G) indicate that the interaction between Cr(III) and collagen is slightly stronger (about 1.8 kJ·mol-1) than Al(III), which is insufficient to assume the large difference in stability of chrome-tanned and alum-tanned leathers. However, ?S of the adsorption process is positive for Cr(III) and negative for Al(III), and the addition of Cr(III) results in bigger conformational change of collagen than Al(III) indicated by both the CD spectra and SEM images, which suggest that the big differences in conformation of collagen induced by Cr(III) and Al(III) may be the foundation of difference in stability. Note de contenu : - EXPERIMENTAL : Materials and chemicals - Experiments - Isolelectric point (pl) measurement of hide powder - Adsorption kinetics - Adsorption isotherms - Circular dichroism measurements
- RESULTS AND DISCUSSIONS : Isoelectric point (pl) of collagenf fibers - The kinetics of Cf(III) and Al(III) adsorption - The adsorption isotherm and thermodynamicsEn ligne : https://drive.google.com/file/d/1G3h9ow1E5gEz7GHM7AHWqWVtEgMWPTTR/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29394
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Code-barres Cote Support Localisation Section Disponibilité 19363 - Périodique Bibliothèque principale Documentaires Disponible Application of Y-shaped polyurethane and polyacrylic acid as a complex retanning agent in aldehyde-tanned goat leather / Shuangquan Lai in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXII, N° 11 (11/2017)
[article]
Titre : Application of Y-shaped polyurethane and polyacrylic acid as a complex retanning agent in aldehyde-tanned goat leather Type de document : texte imprimé Auteurs : Shuangquan Lai, Auteur ; Yong Jin, Auteur ; Hanping Li, Auteur ; Lei Zhang, Auteur ; Xin Yin, Auteur Année de publication : 2017 Article en page(s) : p. 367-376 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Acide polyacrylique
Copolymères -- Synthèse
Copolymères séquencés
Cuirs et peaux -- Analyse
Cuirs et peaux -- Propriétés mécaniques
Cuirs et peaux -- Propriétés organoleptiques
Cuirs et peaux -- Propriétés physiques
Cuirs et peaux de chèvres
Glutaraldéhyde
Morphologie (matériaux)
Polymères amphiphiles
Polyuréthanes
Retannage
Tannage organiqueIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : A kind of Y-shaped amphiphilic block polyurethane copolymers (PUGs) with different molecular weights were successfully synthesized to be used as retanning agent combined with polyacrylic acid (PAA) for modified glutaraldehyde tanned goatskin. The structures of resulting products were characterized by FTIR, and the molecular weights of products were measured with GPC. The application performances were investigated by measuring the organoleptic and physical mechanical properties of resulting leathers according to the alone or combined use of PUG and PAA, the molecular weight of PUG, and the offer percentage of retanning agent. The best performance was found in the leather retanned by PUG750 and PAA complex retanning agent at the total offer percentage of 4 wt%. Finally, the free formaldehyde contents in the leathers retanned with 4 wt% PUG750 and PAA at different pH conditions were analyzed with acetyl acetone colorimetric method. The mechanical properties as well as the fibers morphologies of the experimental and control groups were also investigated. The results demonstrated that when the pH value at the later stage of retanning process was controlled at 4.0 or 3.0, the free formaldehyde content was significantly reduced by 20.3% or 38% respectively ; and the physical mechanical properties of leathers were also very excellent to meet the performance requirements of goatskin garment leathers. According to these results, the method for using PUG and PAA as a complex retanning agent might be a good choice in chrome-free tanning process. Note de contenu : - MATERIALS AND METHODS : Materials - Synthesis of Y-shaped amphiphilic block polyurethane copolymers (PUGs) - Synthesis of polyacrylic acid (PAA) - Fourier Transform Infrared Spectra (FTIR) - Gel permeation chromatography (GPC) - Application of polyurethanes and polyacrylic acid - Analysis of leather properties - Scanning electron microscopy analysis - Determination of free formaldehyde contents in leathers
- RESULTS AND DISCUSSION : Synthesis of polyurethane copolymers and polyacrylic acid - Effect of different retanning agents on the organoleptic and physical properties of leathers - Effect of the molecular weight of PUG on the organoleptic and physical properties of leathers - Effect of the amount of complex retanning agent on the organoleptic and physical properties of leathers - Application of the complex retanning agent under different pH conditionsEn ligne : https://drive.google.com/file/d/1n0hhgDSLoOspbiCVezGLJhDkXewQevzZ/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29395
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Code-barres Cote Support Localisation Section Disponibilité 19363 - Périodique Bibliothèque principale Documentaires Disponible The durability of antimicrobial effect of leathers finished with oregano oil / Elzbieta Bielak in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXII, N° 11 (11/2017)
[article]
Titre : The durability of antimicrobial effect of leathers finished with oregano oil Type de document : texte imprimé Auteurs : Elzbieta Bielak, Auteur ; Ewa Marcinkowska, Auteur ; Justyna Sygula-Cholewinska, Auteur Année de publication : 2017 Article en page(s) : p. 377-386 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antimicrobiens
Cuirs et peaux -- Conservation
Huile essentielle d'origanIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Essential oils introduced into raw materials in the technological process enable leather to gain antimicrobial properties. These properties were examined toward microorganisms potentially pathogenic to humans and causing biodegradation of leather. The article presents an assessment of antimicrobial activity of cowhide lining leathers fatliquored with the addition of oregano oil at concentrations of 1% and 3% per leather weight after one month storage. Additionally, the durability of this activity for leathers with oregano oil at concentration of 3% was confirmed after 12 months. Antimicrobial effect was tested according to PN-EN ISO 20645:2006 Textile fabrics – Determination of Antibacterial Activity – Agar Diffusion Plate Test. Furthermore, to verify the results of antimicrobial durability of leathers within one year after fatliquoring, the method according to ISO 22196:2011 Measurement of antibacterial activity on plastics and other non-porous surfaces was used.
Antimicrobial effect of finished leathers against bacteria Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, yeast Candida albicans and filamentous fungus Scopulariopsis brevicaulis was tested. The obtained results indicated that lining leathers enriched with oregano oil at concentration of 3% per leather weight is characterized by its good and durable antimicrobial effect persisting even one year after adding oil into leather. The results presented in this paper is a continuation of previous studies on animal leather enriching with essential oils.Note de contenu : - Table 1. Antibacterial effect of the antibacterial treatment
- Table 2. Assessment schematic for the growth of filamentous fungi on the agar
- Table 3. As assessment of antimicrobial effect of leathres fatliquored with the addition of oregano oil at concentrations of 1% and 3% per leather weight after 1 and 12 months of storage
- Table 4. Antibacterial activity of the lining leather fatliquored with oregano oil at amount of 3% (per leather weight) to escherichia coli
- Table 5. Antibacterial activity of the lining leather fatliquored with oregano oil at amount of 3% (per leather weight) to staphylococcus aureusEn ligne : https://drive.google.com/file/d/1eKCDCNYAaGeqXsFlouaNU1H2fAQ01Cri/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29396
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Code-barres Cote Support Localisation Section Disponibilité 19363 - Périodique Bibliothèque principale Documentaires Disponible Nonparametric bootstrap method for estimating the upper confidence limits of exposure point concentrations of formaldehyde in fur products - A case study of tongxiang city, China / Yuan Xuzheng in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXII, N° 11 (11/2017)
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Titre : Nonparametric bootstrap method for estimating the upper confidence limits of exposure point concentrations of formaldehyde in fur products - A case study of tongxiang city, China 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. 387-394 Note générale : Bibliogr Langues : Américain (ame) Catégories : Fourrures -- Analyse
Fourrures -- Teneur en formaldehyde
Mesure -- Méthodes statistiquesIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : The distribution characteristics of the formaldehyde (FA) content of fur products produced in Tongxiang City over three consecutive years (2014-2016) were analyzed by the Lilliefors test, quarterback robust statistical method, and kernel density estimation. The bootstrap simulation sampling method was used to calculate the upper confidence limits (UCL) of the exposure point concentration (EPC) of FA. The robustness and rationality of the UCL estimation were verified by the distribution of the mean value of each bootstrap sample dataset. The results showed that their distributions were close to normal distribution but were highly skewed. The one-sided 95% UCL on the mean were 95.45 mg/kg, 93.02 mg/kg and 86.64 mg/kg, which decreased year by year. The Wilcoxon rank sum test indicated that the population distribution of the FA content in 2016 showed a structural improvement over those of the previous two years. Note de contenu : - SAMPLE SOURCES AND METHODS : Case study area : tongxiang city - Samples sources - Method for determination of FA - Data processing method for samples below the LOD - Polymorphic analysis of FA content for every year
- Estimation UCL for EPC of FA for every year
- Pairwise comparison of FA content by wilcoxon rank sum test
- RESULTS AND DISCUSSION : Data processing method for samples below the LOD - Descriptive statistical analysis of the FA content in fur products - Symmetry analysis of distribution of FA content in fur products - Computing UCL and programmed by MATLAB - UCL values and robustness verification - Pairwise comparison of FA content by the wilcoxon rand sum testEn ligne : https://drive.google.com/file/d/1d_Ldj-bt-EwIaewoBJT4Ha4OWKF6Yxxp/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29397
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXII, N° 11 (11/2017) . - p. 387-394[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 19363 - Périodique Bibliothèque principale Documentaires Disponible
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Code-barres | Cote | Support | Localisation | Section | Disponibilité |
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19363 | - | Périodique | Bibliothèque principale | Documentaires | Disponible |