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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Polycaprolactone strengthening keratin/bioactive glass composite scaffolds with double cross-linking networks for potential application in bone repair / Liying Sun in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 4 (Année 2022)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 4 (Année 2022) . - 13 p. Titre : Polycaprolactone strengthening keratin/bioactive glass composite scaffolds with double cross-linking networks for potential application in bone repair Type de document : texte imprimé Auteurs : Liying Sun, Auteur ; Shan Li, Auteur ; Kaifeng Yang, Auteur ; Junchao Wang, Auteur ; Zhengjun Li, Auteur ; Nianhua Dan, Auteur Année de publication : 2022 Article en page(s) : 13 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Composites Ingénierie tissulaire kératines La kératine est une protéine, synthétisée et utilisée par de nombreux êtres vivants comme élément de structure, et également l'exemple-type de protéine fibreuse. La kératine est insoluble, et peut être retrouvée sur l'épiderme de certains animaux, notamment les mammifères, ce qui leur garantit une peau imperméable. Parfois, lors d'une friction trop importante, la kératine se développe à la surface de la peau formant une callosité. Les cellules qui produisent la kératine meurent et sont remplacées continuellement. Les morceaux de kératine qui restent emprisonnés dans les cheveux sont couramment appelés des pellicules. La molécule de kératine est hélicoïdale et fibreuse, elle s'enroule autour d'autres molécules de kératine pour former des filaments intermédiaires. Ces protéines contiennent un haut taux d'acides aminés à base de soufre, principalement la cystéine, qui forment un pont disulfure entre les molécules, conférant sa rigidité à l'ensemble. La chevelure humaine est constituée à 14 % de cystéine. Il y a deux principales formes de kératines : l'alpha-kératine, ou α-keratin, présente chez les mammifères notamment, dont l'humain, et la bêta-kératine, ou β-keratin, que l'on retrouve chez les reptiles et les oiseaux. Ces deux types de kératines ne présentent clairement pas d'homologie de séquence. Chez l'être humain, la kératine est fabriquée par les kératinocytes, cellules se trouvant dans la couche profonde de l'épiderme. Les kératinocytes absorbent la mélanine (pigment fabriqué par les mélanocytes), se colorent et ainsi cette pigmentation de l'épiderme permet de protéger les kératinocytes des rayons ultraviolets du Soleil. (Wikipedia) Poly-e-caprolactone Polymères en médecine Régénération (biologie) Réticulation (polymérisation) Tissu osseux Verre Index. décimale : 668.9 Polymères Résumé : In this study, we aimed at constructing polycaprolactone (PCL) reinforced keratin/bioactive glass composite scaffolds with a double cross-linking network structure for potential bone repair application. Thus, the PCL-keratin-BG composite scaffold was prepared by using keratin extracted from wool as main organic component and bioactive glass (BG) as main inorganic component, through both cross-linking systems, such as the thiol-ene click reaction between abundant sulfhydryl groups of keratin and the unsaturated double bond of 3-methacryloxy propyltrimethoxy silane (MPTS), and the amino-epoxy reaction between amino groups of keratin and the epoxy group in (3-glycidoxymethyl) methyldiethoxysilane (GPTMS) molecule, along with introduction of PCL as a reinforcing agent. The success of the thiol-ene reaction was verified by the FTIR and 1H-NMR analyses. And the structure of keratin-BG and PCL-keratin-BG composite scaffolds were studied and compared by the FTIR and XRD characterization, which indicated the successful preparation of the PCL-keratin-BG composite scaffold. In addition, the SEM observation, and contact angle and water absorption rate measurements demonstrated that the PCL-keratin-BG composite scaffold has interconnected porous structure, appropriate pore size and good hydrophilicity, which is helpful to cell adhesion, differentiation and proliferation. Importantly, compression experiments showed that, when compared with the keratin-BG composite scaffold, the PCL-keratin-BG composite scaffold increased greatly from 0.91 ± 0.06 MPa and 7.25 ± 1.7 MPa to 1.58 ± 0.21 MPa and 14.14 ± 1.95 MPa, respectively, which suggesting the strong reinforcement of polycaprolactone. In addition, the biomineralization experiment and MTT assay indicated that the PCL-keratin-BG scaffold has good mineralization ability and no-cytotoxicity, which can promote cell adhesion, proliferation and growth. Therefore, the results suggested that the PCL-keratin-BG composite scaffold has the potential as a candidate for application in bone regeneration field. Note de contenu : - MATERIALS AND METHODS : Materials - Fabrication of keratin-BG and PCL-keratin-BG composite scaffolds CHARACTERIZATION : Analyses of chemical structure - Morphology observation and porosity detection of scaffolds - Hydrophilicity testing - Mechanical properties - In vitro biological activity evaluation - Statistical analysis - RESULTS AND DISCUSSION : Characterization of chemical structure - Porous morphology of keratin-BG and PCL-keratin-BG scaffolds - Hydrophilicity of scaffolds - Mechanical properties - In vitro mineralization characterization - Biocompatibility–cell viability assay - Table 1 : The radio of calcium to phosphorus (Ca/P) of HA after mineralization in keratin-BG and PCL-keratin-BG scaffolds DOI : https://doi.org/10.1186/s42825-021-00077-w En ligne : https://link.springer.com/content/pdf/10.1186/s42825-021-00077-w.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37565 [article]

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