3D textile-reinforced composites : from manufacturing to structural design / Dimytro Vastukov in JEC COMPOSITES MAGAZINE, N° 121 (05-06/2018)  

[article]  inJEC COMPOSITES MAGAZINE > N° 121 (05-06/2018) . - p. 67-69 Titre : 3D textile-reinforced composites : from manufacturing to structural design Type de document : texte imprimé Auteurs : Dimytro Vastukov, Auteur ; Yang Liu, Auteur ; Chung-Hae Park ; Patricia Krawczak Année de publication : 2018 Article en page(s) : p. 67-69 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse multiéchelle Composites à fibres -- Propriétés mécaniques Modèles numériques Procédés de fabrication Renforts textiles Structures tridimensionnelles Index. décimale : 668.4 Plastiques, vinyles Résumé : Designing structural parts made of 3D textile-reinforced materials demands a deep understanding of the different physical phenomena to be accounted for at the individual steps from manufacturing to exploitation. The process relies on numerical methods to resolve multi-scale material modelling and includes the quantification of various manufacturing effects using advanced experimental techniques. Note de contenu : - Effects of the manufacturing process - Examples of 3D textile composites - Experimental techniques - Material variability in the yarns - Multi-scale material modelling Fig. 1 : Effects of the manufacturing process on 30 textile-reinforced composites : (a) yarn shape distortion after the RTM process (reconstructed from a µCT image) ; b) local fibre packing variability (SEM image showing the horizontal and vertical fibre packing gradients) ; c) broken fibre bundles after the weaving process (reconstructed from µCT data. the image shows the broken fibre in the binder) - Fig. 2 : Two examples of 3D textile-reinforced composites ; b) 3D orthogonal glass fibre composite fil ; and multiaxial composite - Fig. 3 : Measuring weft yarn cross sections ; a) an example showing how the feature points are selected ; b) averaged characteristic cross sections of weft yarns - Fig. 4 : Measuring warp yarn cross section : a) an example showing how the points are selected ; b) averaged characteristic cross sections of warp yarns - Fig. 5 : A representative inter-yarn fibre volume fraction along the thickness and width directions of the L1 section in the weft column - Fig. 6 : The computed local fibre orientations are distributed along the binder path, taking the real model as an example - Fig. 7 : Overview of multi-scale modelling : a) simulted warp-directional stress-strain curves along the experimental upper and lower bounds ; evolution history of di in the matrix/collective warp/weft component ; b) statistical distribution of the damage value when the peak stress value is reached with yarn breakage in the warp yarns (d1) (loading along the warp direction) En ligne : https://drive.google.com/file/d/1MaMCqgg53tlZ6NBYtc_Qdxj1nI2se_WV/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30950 [article]

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Changes to the collagen structure using vibrational spectroscopy and chemometrics : a comparison between chemical and sulfide-free leather process / Megha Mehta in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVI, N° 11 (11/2021)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVI, N° 11 (11/2021) . - p. 379-387 Titre : Changes to the collagen structure using vibrational spectroscopy and chemometrics : a comparison between chemical and sulfide-free leather process Type de document : texte imprimé Auteurs : Megha Mehta, Auteur ; Yang Liu, Auteur ; Rafea Naffa, Auteur ; Mark Waterland, Auteur ; Geoff Holmes, Auteur Année de publication : 2021 Article en page(s) : p. 379-387 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse multivariée Chimiométrie Collagène Enzymes protéolytiques Une enzyme protéolytique est une enzyme capable de couper une protéine en plusieurs fragments ou peptides. La trypsine, la papaïne, la pepsine, la chymotrypsine, la plasmine, la subtilisine... sont capables de couper une protéine, chaque enzyme étant spécifique de certains sites particuliers de cette protéine. C'est ainsi, par exemple, qu'une immunoglobuline G est découpée par la papaïne en un fragment Fc et deux fragments Fab, comme l'a montré Porter en 1959. Epilage enzymatique Matériaux -- Modifications chimiques Radiométrie Spectroscopie Raman Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Chemical and physical changes take place when hides and skins are processed to leather that affect the quality and strength of the material. Understanding the structure at each leather-making stage is the basis of this study but also intend to improve the process through a biochemical approach, employing a proteolytic enzyme for processing leather more cleanly with reduced environmental impact. Raman and ATR-FTIR spectroscopy in conjunction with chemometrics was used to investigate each leather-making stage from fresh green cattle hide to dry crust leather. The changes in proteins, lipids, nucleic acids and other biomolecules with leather processing was measured and reported using three novel Raman ratiometric markers, 920/1476, 1345/1259 and 1605/1476 cm-1, to discriminate the structural changes in collagen of hide using standard chemical and enzymatic method. Amide I band was deconvoluted to investigate thecollagen secondary structures using curve fitting by Gaussians function. The results of Principal Component Analysis are well-corroborated with the ratiometric markers of structural changes. Note de contenu : - EXPERIMENTAL : Materials - Enzymatic depilation - Data acquisition and spectral processing - RESULTS AND DISCUSSION : Fundamental characteristics of Raman spectra of standard and enzymatic processed hide - Radiometric analysis - Alterations in collagen network - Multivariate analysis DOI : https://doi.org/10.34314/jalca.v116i11.4659 En ligne : https://drive.google.com/file/d/1O4r23to9vBK4aAxPgMJizfFD5zzgmQ2M/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36575 [article]

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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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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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Monitoring the mode of action of synthetic and natural biocides against Aeromonas hydrophila by Raman spectroscopy and chemometrics / Megha Mehta in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 3 (Année 2021)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 3 (Année 2021) . - 15 p. Titre : Monitoring the mode of action of synthetic and natural biocides against Aeromonas hydrophila by Raman spectroscopy and chemometrics Type de document : texte imprimé Auteurs : Megha Mehta, Auteur ; Yang Liu, Auteur ; Mark Waterland, Auteur ; Geoff Holmes, Auteur Année de publication : 2021 Article en page(s) : 15 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Aeromonas hydrophila Analyse multivariée Antimicrobiens Chimiométrie Cuirs et peaux -- Conservation Huile essentielle d'origan Inhibiteurs (chimie) Spectroscopie Raman Thiocyano-méthylthiobenzotiazole Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : We have investigated the mode of action of synthetic biocides, (2-(thiocyanomethylthio) benzothiazole(TCMTB), dichlorophen, (commonly used in leather industry for preservation) and natural biocides, oregano and eucalyptus oils, on Aeromonas hydrophila using Raman spectroscopy in collaboration with multivariate analysis and 2D correlation spectroscopy to evaluate whether Raman spectra acquired contained valuable information to study the action of biocides on bacterial cells. The growth of A. hydrophila in clear and outer edge zone of inhibition differ in their reaction with different biocides, which allows us to highlight the differences as a characteristic of two kinds of bacteria. Such classification helps identify oregano oil as the most effective biocide by altering clear and outer edge zone of bacteria. Standard disk diffusion assay method was used for screening biocide bacteria interactions and later analysed by Raman spectroscopy. The paper also presents the introduction of TCMTB and oregano oil into leather processing stages to examine and determine the antimicrobial effect as an application to real-world setting. Therefore, we conclude that Raman spectroscopy with appropriate computational tools constitutes a powerful approach for screening biocides, which provide solutions to all the industries using biocides including leather industry, considering the potentially harmful effect of biocides to humans and the environment. Note de contenu : - MATERIALS AND METHODS : Biocides and bacteria - Biocides, bacteria and leather treatment - Data acquisition and Raman spectral processing - RESULTS AND DISCUSSION : Disk diffusion agar plate test - Raman spectroscopy identifies biomolecular changes due to biocide treatment - Multivariate analysis - Two-dimensional correlation spectroscopy (2D-COS) - Antimicrobial effect of leather treated with biocides - Table 1 : Disk diffusion determined zones of inhibition (mm) for A. hydrophila strain after treatment with TCMTB, DCP, oregano oil and eucalyptus oil DOI : https://doi.org/10.1186/s42825-021-00062-3 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-021-00062-3.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37546 [article]

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Oxidative stress in the skin : Impact and related protection / Juanjuan Chen in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 43, N° 5 (10/2021)  

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Synthesis, characterisation and application of novel valonia tannin based waterborne polyurethane with natural colour / Yang Liu in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 103, N° 3 (05-06/2019)  

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Synthesis of tannic acid waterborne polyurethane in application for leather finishing / Haihang Luo in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 104, N° 3 (05-06/2020)  

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