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Particle size evolution of chrome tanning agent on tanning effect / Yahui Wang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIV, N° 8 (08/2019)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIV, N° 8 (08/2019) . - p. 279-286 Titre : Particle size evolution of chrome tanning agent on tanning effect Type de document : texte imprimé Auteurs : Yahui Wang, Auteur ; Haojun Fan, Auteur ; Yi Chen, Auteur ; Jun Yan, Auteur Année de publication : 2019 Article en page(s) : p. 279-286 Note générale : Bibliogr. Langues : Américain (ame) 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. pH -- Mesure Stabilité hydrothermale Taille des particules Tannage au chrome Température Température de retrait Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : In a traditional method of chrome tanning, the particle size (PS) of tanning agent is critical for its penetration and the performance of resultant leather. The temperature, pH value and concentration of chrome solution are the important parameters to influence the size scale of the chromium complex. In present study, the PS evolution of chrome tanning agent (CTA) with pH value and temperature changes was investigated firstly, then the influence of the evolution of PS on the tanning process and hydrothermal stability of crust leather was also investigated. The results indicated that with the temperature varied from 25°C to 30°C and 35°C, the pH of the chrome solution increased from 2.5 to 3.8, the PS of CTA increased from 982 nm to 2899 nm, 1265 nm to 3384 nm and 1289 nm to 3630 nm, respectively, showing a rapid increasing tendency. Correspondingly, due to the PS of CTA increased, the chromium absorption rate increased from 31.0% to 53.6% at 25°C, 33.8% to 55.9% at 30°C and 34.5% to 56.4% at 35°C, whilst the uniformity of the chromium distribution in crust leather was gradually reduced. At the same initial tanning temperature, the shrinkage temperature (Ts) of wet blue tend to increase first and then decrease with the increase of the CTA’s PS, and reached above 100°C when the PS was in a range from 2000 nm-2700 nm. As the PS continues to increase, the inner layer was insufficient tanned due to excessive tanning of surface, leading to a decrease in hydrothermal stability of crust leather. Note de contenu : - EXPERIMENTAL : Materials - Preparation chrome tanning solution with different pH value - Particle size measurement - Tanning trial - Property assessments of tanned leathers determination of chromium concentration in spent tanning solutions - Determination of chromium content and distribution in tanned leathers - Shrinkage temperature of tanned leathers - RESULTS AND DISCUSSION : Evaluations PS of CTA with pH and temperature - The effect of PS on absorptivity of chromium - Effect of PS on chromium distribution in tanned leathers - Hydrothermal stability of tanned leathers En ligne : https://drive.google.com/file/d/1FFPGoUDxNCsOlGVOtl9FbehxOfxCTAjU/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32787 [article]

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Microwave irradiation : an innovative routine to promote goat skin chrome tanning process / Jinweil Zhang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIV, N° 8 (08/2019)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIV, N° 8 (08/2019) . - p. 287-292 Titre : Microwave irradiation : an innovative routine to promote goat skin chrome tanning process Type de document : texte imprimé Auteurs : Jinweil Zhang, Auteur ; Wuyomg Chenand, Auteur ; Carmen Gaidau, Auteur Année de publication : 2019 Article en page(s) : p. 287-292 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuirs et peaux de chèvres Micro-ondes Tannage au chrome Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The chemical reaction with microwave assistant has faster rate, higher yield and milder condition. In order to study the influence of microwave on chrome tanning process, the chrome tanning with microwave heating (MW) was carried out at different initial pH and terminal pH regraded as experimental samples and with water bath heating (WB) at corresponding condition was control in the study. The shrinkage temperature, chrome content and chrome distribution of wet blue were determined to obtain the influence of microwave on tanning effect. In addition, the pickled skins were modified by esterification and deamination and then the modified skins were tanned under microwave to know whether microwave would affect the combination sites between collagen and chromium complex or not. The results showed that microwave had positive effect on chrome tanning process, representing as higher shrinkage temperature and chrome content as well as more uniform chrome distribution for leather. Especially, the shrinkage temperature of MW leather exceeded 100°C when tanning terminal ending pH was only 3.3, indicating the tanning with microwave assistance could complete under a lower pH than the usual. Moreover, the combination sites between collagen and chromium of MW leather were the same as WB, indicating the effect of microwave could not change the combination sites. In sum, microwave could promote chrome tanning and make it finish at a milder condition, which might innovate the tanning technology and provide a new chrome tanning method in the future. Note de contenu : - EXPERIMENTAL : Materials - Tanning method : chrome tanning at different initial pH - Chrome tanning at different terminal Ph - Deaminated skin tanning - Esterified skin tanning - Test method : Ts measurement - Leather chrome content measurement - Chrome distribution uniformity determination - SEM/EDS analysis - RESULTS AND DISCUSSION : Influence of microwave on different initial pH chrome tanning - Influence of microwave on different final chrome tanning Ph - Influence of microwave on chrome combination sites En ligne : https://drive.google.com/file/d/15o7pNS84BLYZpTRQUJB9PsMjtE37Xs-T/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32788 [article]

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Organic-inorganic hybrid coatings via sol-gel route for leather finishing / L. de Ferri in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIV, N° 8 (08/2019)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIV, N° 8 (08/2019) . - p. 293-299 Titre : Organic-inorganic hybrid coatings via sol-gel route for leather finishing Type de document : texte imprimé Auteurs : L. de Ferri, Auteur ; A. Lorenzi, Auteur ; F. Tassi, Auteur ; Lorenza Draghi, Auteur Année de publication : 2019 Article en page(s) : p. 293-299 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Alcoxyde de silicone Angle de contact Cuirs et peaux -- Finition Imperméabilisation Orthosilicate de tétraéthyle L'orthosilicate de tétraéthyle (TEOS) est un composé chimique de formule Si(OCH2CH3)4 ou plus simplement Si(OEt)4; l'abréviation TEOS (pour tetraethylorthosilicate) est généralement utilisée dans l'industrie du sol-gel, où il est intensivement étudié. La majorité des études en sol-gel pour des sols de silices ont utilisé ce produit comme précurseur. Le TEOS est généralement produit par alcoolyse du tétrachlorure de silicium SiCl4 dans de l'éthanol CH3CH2OH : SiCl4 + 4 CH3CH2OH → Si(OCH2CH3)4 + 4 HCl. Il est utilisé pour la réticulation de silicones et possède certaines applications comme précurseur du dioxyde de silicium SiO2 dans l'industrie des semi-conducteurs6 dans le cadre d'une réaction sol-gel. La propriété remarquable du TEOS est en effet de former du SiO2 par simple hydrolyse en libérant de l'éthanol CH3CH2OH : Si(OCH2CH3)4 + 2 H2O → SiO2 + 4 CH3CH2OH. Revêtements protecteurs Sol-gel, Procédé Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Despite its popularity in other industries, including textiles, for the preparation of inorganic and hybrid coatings, the use of sol-gel for leather finishing is a barely explored field. To exploit its unique and versatile chemistry, we have here evaluated the potential of sol-gel route for preparing protective coatings and achieve, at the same time, water- repellency on treated leather. To this aim, tetra-ethyl-ortho-silicate (TEOS) and functionalized Si-alkoxides, containing either alkyl or fluorinated groups were selected and compared. The results of characterization indicate that, for the chosen formulations, alcohol-based sols were patently more effective than their water-based counterparts. Very high contact-angles were obtained for both alkyl- and fluorinated alkoxides, but, not surprisingly, fluorinated coatings provided a longer-lasting hydro-repellency. Sols well preserved leather grain, with no patent accumulation on pores or ridges, while only minor changes in color was observed in most formulations. Overall, our results suggest that a careful optimization of sol-gel formulation can offer unexplored, versatile and very effective solutions in leather finishing. Note de contenu : - Synthesis and deposition of the sols - Characterization : Pick-up - Scanning Electron Microscopy (SEM) - Water contact angle - Oil repellency En ligne : https://drive.google.com/file/d/1g7VJk-zQygBYCat7QBVm7DvpvBfd2cRn/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32789 [article]

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Inside into understanding incorporation of glycidoxypropyltrimethoxysilane for improving hydrothermal stability and porous structure of silicic acid tanned leather / Zetian Zhang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIV, N° 8 (08/2019)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIV, N° 8 (08/2019) . - p. 300-312 Titre : Inside into understanding incorporation of glycidoxypropyltrimethoxysilane for improving hydrothermal stability and porous structure of silicic acid tanned leather Type de document : texte imprimé Auteurs : Zetian Zhang, Auteur ; Jun Liu, Auteur ; Junchao Wang, Auteur ; Zhengjun Li, Auteur Année de publication : 2019 Article en page(s) : p. 300-312 Note générale : Bibliogr. Langues : Américain (ame) Catégories : 3-Glycidoxypropyltrimethoxysilane Cuirs et peaux -- Analyse Dénaturation (chimie) Essais accélérés (technologie) Porosité Stabilité hydrothermale 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 Tannage synthétique Température de retrait Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Tanning with silicic acid, a kind of silicon-containing materials, is considered as a more environmentally benign process; however, the obtained leather would become stiff and brittle during storage in spite of possessing acceptable shrinkage temperature (Ts). Herein, we incorporated organosilicon material attaching silicon atoms with T linkage structure (e.g. glycidoxypropyltrimethoxysilane, GPTMS) in the leather-making process to investigate hydrothermal stability and porous structure, in particular their variation along with different storage time, through Ts determination, DSC analysis, SEM observation and SEM-EDS test. The results confirmed that the introduction of GPTMS stabilized properties of the resultant leather during accelerated ageing process, which may be ascribed to that GPTMS could prevent silicon hydroxyl groups existing in collagen fiber matrix from further condensation. Besides, the tanning mechanism of chrome-free tanning agent based on silicon materials such as silicic acid and GPTMS was investigated preliminarily by means of FT-IR and XPS analysis, indicating hydrogen bonds between silicon hydroxyl groups and amino groups in collagen molecules, and the covalent bonding formed by epoxy group of GPTMS and carboxyl groups of collagen fibers are beneficial to improvement of the properties of silicon-based materials tanned leather. These findings provide an effective and promising strategy to control condensation of silicon hydroxyl groups, and are of great significance to the development of a chrome-free tanning technology based on silicon materials. Note de contenu : - EXPERIMENTAL : Materials - Preparation of the silicic acid solution - Tanning process and accelerated ageing test of leather samples selection of tanning conditions - Addition of GPTMS and accelerated aging test - Test of the shrinkage temperature - Test of the denaturation temperature - Measurement of the total porosity - SEM observation and SEM-EDS analysis - FT-IR measurement - XPS measurement - RESULTS AND DISCUSSION : Optimization of parameters in silicic acid tanning process - Effect of GPTMS on stability and porous structure of leather - Effect of GPTMS and accelerated ageing on stability of leather - Effect of GPTMS and accelerated ageing on porous structure of leather - Preliminary research of tanning mechanism En ligne : https://drive.google.com/file/d/1CaTbsbMP4-jjhiCVqGzSvRDqH_qdpHej/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32790 [article]

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