A chrome-free combination tanning strategy : based on silicic acid and plant tannin / Zetian Zhang in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 3 (Année 2021)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 3 (Année 2021) . - 13 p. Titre : A chrome-free combination tanning strategy : based on silicic acid and plant tannin Type de document : texte imprimé Auteurs : Zetian Zhang, Auteur ; Yang Liu, Auteur ; Junchao Wang, Auteur ; Taoling Xie, Auteur ; Liying Sun, Auteur ; Zhengjun Li, Auteur Année de publication : 2021 Article en page(s) : 13 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Angle de contact Caractérisation Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés physiques Eaux usées -- Analyse Humidité -- Absorption:Eau -- Absorption Silicique, Acide Stabilité au stockage Stabilité thermique Tanins végétaux Tannage chrome free 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 Température de retrait Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Silicic acid, commonly derived from cheap and easily available sodium silicate, has recently received great attention for application in leather industry to produce ecological leather with a cleaner approach. However, leather tanned with silicic acid alone is poor in storage stability, which limits its practical application in leather production. In this work, a new environment-friendly combination tannage based on silicic acid and plant tannin was developed to address this issue along with improving the comprehensive performances of leather. The obtained leather was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and so on. The results showed that compared with leather tanned with silicic acid alone, the leather tanned with this combination method possessed improved thermal stability, enhanced mechanical properties, acceptable softness, appropriate hydrophilicity, and especially enhanced storage stability. More importantly, the combination tanned leather with 1:1 of the mass ratio of silicic acid to vegetable tannin (composed of valonea extract and mimosa extract with the same weight) had more prominent comprehensive performances. In addition, the results demonstrated that hydrogen bonding played an important role in the combination tanning process. Furthermore, the hydrogen bonds generated between phenolic hydroxyl groups of polyphenols with silicon hydroxyl groups of silicic acid molecules inhibited the excessive condensation of Si-OH groups between themselves. Subsequently, the assessment of environmental impact revealed the value of BOD5/COD of the wastewater produced in this combination tanning process is more than 0.3, indicating the chrome-free combination tannage based on silicic acid and plant tannin was an environment-friendly tanning technology. These findings therefore indicated that a new chrome-free tanning method with silicon and biomass materials as main tanning agents has potential practical application prospect in leather production. Note de contenu : - EXPERIMENTAL : Materials - Tanning process - Characterization - RESULTS AND DISCUSSION : Thermal stability - Physical and mechanical properties - Water absorption and contact angle - Porous structure and micromorphology - Chemical structure characterization - Waste water assessment - Table 1 : Silicic acid-vegetable tannin combination tanning process - Table 2 : Shrinkage temperature of the samples - Table 3 : Weight loss rate and Tmax of the samples at different storage time - Table 4 : Analysis results of tannery wastewater DOI : https://doi.org/10.1186/s42825-021-00058-z En ligne : https://link.springer.com/content/pdf/10.1186/s42825-021-00058-z.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37541 [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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Interaction between amphoteric polymer and silicic acid tanned leather : Ingenious regulation of ph based on isoelectric point / Ze Liang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVIII, N° 10 (10/2023)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVIII, N° 10 (10/2023) . - p. 403-416 Titre : Interaction between amphoteric polymer and silicic acid tanned leather : Ingenious regulation of ph based on isoelectric point Type de document : texte imprimé Auteurs : Ze Liang, Auteur ; Zetian Zhang, Auteur ; Yang Liu, Auteur ; Zhengjun Li, Auteur Année de publication : 2023 Article en page(s) : p. 403-416 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Caractérisation Composés amphotériques Cuirs et peaux -- Propriétés physiques Huile de ricin et constituants Point isoélectrique En biochimie, le point isoélectrique (pI) ou potentiel hydrogène isoélectrique (pHI) est le pH auquel une molécule est sous forme d'ion mixte ou, en physico-chimie, le pH d'une solution aqueuse dans laquelle un solide existe sous un potentiel électrique neutre. En physico-chimie : Selon Bolger, le caractère acide ou basique d'une surface s'exprime par son point isoélectrique " Is ou IEPS (Iso Electric point for the surface) " ou point de charge nulle " PCN ou PZC (Point of Zero Charge) ", défini comme étant le pH de la solution aqueuse dans laquelle le solide existe sous un potentiel électrique neutre. Si le pH de la solution est basique, la surface est acide, et inversement. La différence entre le PZC et l'IEPS est basée sur le phénomène d'adsorption spécifique. On peut considérer que si la grandeur mesurée ne dépend pas de la solution utilisée pour la mesurer (pH, concentration, nature des ions), alors on a affaire à un PZC. Dans le cas contraire, c'est un IEPS que l'on mesure. Par exemple, quand la mesure de goutte sessile à deux liquides est utilisée, on considère en général qu'il n'y a pas adsorption des ions de cette goutte et que la goutte déplace complètement l'alcane qui sert de deuxième liquide: on est alors en présence d’un PZC. Au contraire, dans les mesures de potentiel d'écoulement (streaming potential), la solution joue un rôle important et c'est un IEPS que l'on mesure. Enfin, la charge nette se définit grâce au pH de la solution aqueuse dans laquelle la surface métallique existe, dans un état électriquement neutre (c’est-à-dire [M-OH2+ surf]=[M-O- surf]) et au PZC. - Si pH < PZC alors la charge nette est positive - Si pH > PZC alors la charge nette est négative. Il existe plusieurs méthodes expérimentales permettant de décrire l’état acido-basique de la surface : la mesure du potentiel d’écoulement, la photoélectrochimie, la mesure de l’angle de contact, et la spectroscopie XPS. Polyaddition Polymères -- Synthèse Polymères en émulsion Produits de nourriture du cuir Silicique, Acide Tannage Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Silicic acid-based tanning system is an effective and promising chrome-free tanning technology, and it is urgent to develop compatible post-tanning processes. Fatliquoring is one of the key procedures to determine the quality of resulted leather and fatliquoring agents mainly play the role of an effective softer/ plasticizer in leather production. However, there is a mismatch between most commercial fatliquoring agents (mainly compatible with chrome tanned leather) and silicic acid tanned leather (named SATL). Herein, an amphoteric polymer emulsion (APE) was prepared by free radical polymerization using methacryloxyethyl trimethyl ammonium chloride (DMC), 2-acrylamido-2-methylpropanesulfonate (AMPS), lauryl methacrylate (LMA), dimethylaminoethyl methacrylate (DMAEMA) as monomers. And in order to improve the lubricating property, APE was further compounded with castor oil to obtain an amphoteric fatliquoring agent (named COAPE). Comprehensive characterization showed that the amphoteric (pI=8.22) and amphiphilic APE could reduce the surface tension of water to 38.6 mN/m. The fatliquoring process was controlled by ingenious regulation of pH based on isoelectric points (pIs) of APE and SATL. In the initial stage, the pH of the bath was adjusted to be lower than the pIs of APE and SATL, amphoteric polymer molecules could easily penetrate into SATL leather as they are all positively charged. While during the fixing stage, the pH of the bath was adjusted between the pIs of APE and SATL, so the electrostatic interaction between amphoteric polymer molecules and SATL leather, as well as the aggregation of amphoteric polymers can promote their combination synergistically. As a fatliquoring agent, the application of COAPE demonstrated that its absorpotion rate (90.5%) was much higher than anionic commercial fatliquoring agent (63.2%), thus imparting SATL leather better softness (6.5 mm), elongation at break (95.5%) and tensile strength (11.6 N/mm2). These findings therefore provided scientific basis and technical support for the application of amphoteric materials to silicic acid-modified collagen matrix and would promote the practical application of silicic acid-based chrome-free tanning technology. Note de contenu : - EXPERIMENTAL : Materials - Synthesis of amphoteric polymer emulsion (APE) and amphoteric fatliquoring agent (COAPE) - Characterization and properties of APE and the amphoteric polymer - Application of APE and COAPE in leather fatliquoring process - RESULTS AND DISCUSSION : Characterization and properties of APE and the amphoteric polymer - Insight into interaction between amphoteric polymer and silicic acid tanned leather - Table 1 : Fatliquoring process - Table 2 : Fatliquoring agent and pH value of bath liquid used in different fatliquoring schemes - Table 3 : Physical properties of SATL leather treated with different fatliquoring agents DOI : https://doi.org/10.34314/jalca.v118i10.8229 En ligne : https://drive.google.com/file/d/13AQaPMWZmhlaEeSA3efdY8mtnqf7Tuiw/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39939 [article]

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