Dépouillements

Investigation of the solubility and dispersion degree of calf skin collagen in ionic liquids / Sicong Liu in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 12 p. Titre : Investigation of the solubility and dispersion degree of calf skin collagen in ionic liquids Type de document : texte imprimé Auteurs : Sicong Liu, Auteur ; Qian Li, Auteur ; Li Guoying, Auteur Année de publication : 2019 Article en page(s) : 12 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Bovins -- Races Chimie analytique Collagène Collagène -- Analyse Collagène -- Solubilité Dispersions et suspensions Liquides ioniques Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The dissolution of collagen in ionic liquids (ILs) was highly dependent on the polarity of ILs, which was influenced by their sorts and concentrations. Herein, the solubility and dispersion degree of collagen in two sorts of ILs, namely 1-ethyl-methylimidazolium tetrafluoroborate ([EMIM][BF4]) with low polarity and 1-ethyl-3-methylimidazolium acetate ([EMIM][Ac]) with high polarity in a concentration range from 10% to 70% at 10 °C were investigated. When 150 mg of collagen was added to 30 mg of ILs, the minimum soluble collagen concentration was 0.02 mg/mL in 70% [EMIM][BF4] with lowest polarity and the maximum was 3.57 mg/mL in 70% [EMIM][Ac] with highest polarity, which indicates that soluble collagen and insoluble collagen fibers were both present. For insoluble collagens, differential scanning calorimetry showed that the thermal-stability was weakened when increasing the ILs concentration and polarity, and the fiber arrangement was looser with a more uniform lyophilized structure, observed by atomic force microscopy and scanning electron microscopy. For soluble collagens, electrophoresis patterns and Fourier transform infrared spectroscopy showed that no polypeptide chain degradation occurred during dissolution, but the thermal denaturation temperature decreased by 0.26 °C~ 7.63 °C with the increase of ILs concentrations, measured by ultra-sensitive differential scanning calorimetry. Moreover, the aggregation of collagen molecules was reduced when ILs polarity was increased as determined by fluorescence measurements and dynamic light scattering, which resulted in an increased loose fiber arrangement observed by atomic force microscopy. If the structural integrity of collagen needs to be retained, then the ILs sorts and concentrations should be considered. Note de contenu : - EXPERIMENTAL : Materials - Processing collagen with ILs - Collagen solubility in ILs - DSC of insoluble collagen fibrils - SEM of insoluble collagen fibrils - AFM measurements of insoluble and soluble collagen - SDS–PAGE patterns of soluble collagen - FTIR of soluble collagen - Fluorescence measurements of soluble collagen - DLS measurements of soluble collagen - RESULTS AND DISCUSSION : Solubility of collagen in ILs - Thermal analysis of insoluble collagen fibrils - SEM images of insoluble collagen fibrils - AFM images of insoluble collagen fibrils - SDS-PAGE patterns of soluble collagen - FTIR spectra analysis of soluble collagen - Thermal analysis of soluble collagen - Fluorescence analysis of soluble collagen - DLS analysis of soluble collagen - AFM images of soluble collagen - Table 1 The concentration of soluble collagen in different ILs and concentrations - Table 2 Thermodynamic parameters of Col and collagen samples dissolved in different concentrations of [EMIM][Ac]a DOI : https://doi.org/10.1186/s42825-019-0013-9 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0013-9.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36945 [article]

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Homogeneous Zr and Ti co-doped SBA-15 with high specific surface area : preparation, characterization and application / Qiang Taotao in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 12 p. Titre : Homogeneous Zr and Ti co-doped SBA-15 with high specific surface area : preparation, characterization and application Type de document : texte imprimé Auteurs : Qiang Taotao, Auteur ; Yajuan Xia, Auteur ; Zhao Jing, Auteur Année de publication : 2019 Article en page(s) : 12 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Absorbants et adsorbants Adsorption Caractérisation Chimie analytique Composés inorganiques -- Synthèse Santa Barbara Amorphous-15 Santa Barbara Amorphous-15 (SBA-15) is a highly stable mesoporous silica sieve developed by researchers at the University of California at Santa Barbara. It gets it high hydrothermal and mechanical stability from a framework of uniform hexagonal pores that feature a narrow pore-size distribution and a tunable pore diameter of 5nm to 15nm, but, most significantly, from its relatively thick walls, which range between 3.1nm and 6.4nm. SBA mesoporous silica 15 has a high internal surface area, which lends itself to various applications, including environmental adsorption and separation, advanced optics, and catalysts. (ACS Materials) Surfaces (technologie) Tannage Thermodynamique Titane Zirconium Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A facile synthesis procedure is proposed to prepare homogeneous Zr and Ti co-doped SBA-15 (Zr-Ti-SBA-15) with high specific surface area of 876.0 m2 g− 1. Based on “masking mechanism” from tanning, lactic acid was used as masking agent to obtain the uniform distribution of Zr and Ti species in the SBA-15 framework. The obtained materials were characterized by powder X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms, scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron (XPS). The results reveal that in mesoporous materials, the presence of lactic acid gives rise to the uniform distribution of Zr and Ti species. The adsorption equilibrium and kinetic studies of Zr-Ti-SBA-15 materials show that the adsorption process conforms to the Langmuir isotherm and pseudo-second-order kinetic model, respectively. Regenerational experiments show that the Zr-Ti-SBA-15 displays a significant adsorption ability for methylene blue (MB) (up to 291.6 mg/g), along with good reusability, indicating promising potentials of commercialization. Methodologically, this work provides a wide range of possibilities for further development of SBA-15 based on bimetallic and sewage disposal. Note de contenu : - EXPERIMENTAL SECTION : Materials - Preparation of Zr-Ti -SBA-15 - Characterization of Zr-Ti-SBA-15 - Adsorption measurement - Regeneration experiment - RESULTS AND DISCUSSION : XRD characterization - N2 adsorption-desorption - TEM and SEM characterization - EDS characterization - XPS characterization - Adsorption measurement of Zr-Ti-SBA-15 - Kinetic analysis - Adsorption isotherms - Thermodynamics analysis - Regeneration experiment of Zr-Ti-SBA-15 - Table 1 XRD texture properties of the samples - Table 2 Textural parameters of the samples - Table 3 The pseudo-first-order and pseudo-second-order kinetic model parameters for MB adsorption on Zr-Ti-SBA-15 composite - Table 4 Isothermal parameters for MB adsorption on Zr-Ti-SBA-15 composite - Table 5 Comparison of the maximum adsorption capacity of different adsorbents - Table 6 The values of thermodynamics parameters for MB adsorption on Zr-Ti-SBA-15 - Table 7 The leaching data of Zr and Ti during desorption process DOI : https://doi.org/10.1186/s42825-019-0004-x En ligne : https://link.springer.com/content/pdf/10.1186/s428 Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36946 [article]

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Epoxidized methyl ricinoleate bio-plasticizer with a pendant acetate ester for PVC artificial material : circumventing existing limit on achievable migration resistance / Siyu Pan in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 10 p. Titre : Epoxidized methyl ricinoleate bio-plasticizer with a pendant acetate ester for PVC artificial material : circumventing existing limit on achievable migration resistance Type de document : texte imprimé Auteurs : Siyu Pan, Auteur ; Delong Hou, Auteur ; Haojun Fan, Auteur Année de publication : 2019 Article en page(s) : 10 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Acides gras Caractérisation Chlorure de polyvinyle Composés organiques -- Synthèse Epoxydation Esters méthyliques Huile de ricin et constituants Phtalates -- Suppression ou remplacement Plastifiants Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Processing polyvinyl chloride (PVC) artificial material requires plasticizer that softens the PVC coating. Currently, utilizing unsaturated fatty acid methyl esters to obtain epoxidized fatty acid methyl ester (EFAME) bio-plasticizers constitutes an environmentally responsible solution to substitute conventional ortho-phthalates that are endocrine disruptors or probable carcinogens. However, commercial EFAMEs, even with the highest epoxy value (ca. 5.5–5.8%) so far, still suffer from fast leaching from the PVC matrix, burdening the environment and shortening lifespan of the artificial material. Here, we report a proof-of-principle demonstration of a new strategy to obtain migration-resistant EFAME that harnesses the midchain hydroxyl of methyl ricinoleate and covalently attachment of a pendant acetate ester. Despite a low epoxy value (3.0%), the engineered bio-plasticizer displays significantly suppressed migration in multiple scenarios compared with one conventional EFAME with much higher epoxy value (5.8%). Circumventing the limit confronting previous strategy that highlights the sole contribution of epoxy value to achievable migration resistance, the rationale herein may provide guidance for designing new EFAMEs with comparable performance to ortho-phthalates, thus bringing the old and oft-maligned PVC artificial material industry one step closer to sustainability. Note de contenu : - Materials -Synthesis of epoxidized methyl ricinoleate with a pendant acetate ester (EMRA) - Preparation of plasticized PVC membranes - Characterization - Simulation details - Table 1 : Physicochemical parameters of EMRA and corresponding intermediates - Table 2 : Composition of MR, MRA, and EMRA identified by comparing the experimental mass spectra of the components in Fig. 3 against NIST08 mass spectral library DOI : https://doi.org/10.1186/s42825-019-0006-8 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0006-8.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36947 [article]

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Insights into functional polymer-based organic-inorganic nanocomposites as leather finishes / Qianqian Fan in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 10 p. Titre : Insights into functional polymer-based organic-inorganic nanocomposites as leather finishes Type de document : texte imprimé Auteurs : Qianqian Fan, Auteur ; Ma Jianzhong, Auteur ; Qunna Xu, Auteur Année de publication : 2019 Article en page(s) : 10 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Antibactériens Cuirs et peaux -- Finition Matériaux -- Propriétés fonctionnelles Nanoparticules Polymères organiques-inorganiques Résistance à l'humidité:Résistance à l'eau Revêtement auto-nettoyant Sol-gel, Procédé Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Nowadays, the increasing demands from consumer challenges the traditional leather products. Traditional polymer leather finishes gradually lose their dominant position in the market. To address this issue, recent research effort has been devoted to developing polymer-based organic-inorganic nanocomposite leather finishes due to their various functional properties including antibacterial, self-cleaning and water-resistant property. In this review, we provide a comprehensive overview of synthesis of polymer-based organic-inorganic nanocomposites and their application as functional leather finishes. With the perspective of their properties and current challenges, an outlook in the future development about crafting functional and high-quality leather finishes are further proposed. Note de contenu : - SYNTHESIS OF POLYMER-BASED ORGANIC-INORGANIC NANOCOMPOSITES : Sol-gel processing - Blending - In situ method - APPLICATION OF POLYMER-BASED ORGANIC-INORGANIC NANOCOMPOSITES AS FUNCTIONAL LEATHER FINISHES : Antibacterial leather finishes - Water resistant leather finishes - Self-cleaning leather finishes - Other functional leather finishes DOI : https://doi.org/10.1186/s42825-019-0005-9 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0005-9.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36948 [article]

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Factors affecting mass transfer of protease in pelt during enzymatic bating process / Ying Song in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 10 p. Titre : Factors affecting mass transfer of protease in pelt during enzymatic bating process Type de document : texte imprimé Auteurs : Ying Song, Auteur ; Siqi Wu, Auteur ; Qian Yang, Auteur ; Hao Liu, Auteur ; Yunhang Zeng, Auteur ; Bi Shi, Auteur Année de publication : 2019 Article en page(s) : 10 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Confitage Le confitage est une action biochimique effectuée au moyen de produits enzymatiques, qui a pour but de dégrader les fibres élastiques, contribuant ainsi à augmenter la souplesse du cuir. En outre, les enzymes complètent la dégradation des résidus épidermiques, donnant ainsi une fleur plus propre et plus lisse. Cuirs et peaux Electrostatique Peptidases Poids moléculaires Tension superficielle Transfert de masse Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Bating pelt with protease is an important process, which removes unwanted non-collagenous proteins from the pelt and moderately disperse hide collagen network. However, the grain surface, may be excessively hydrolyzed during bating due to the longer retention time of protease in the grain than in the middle layer caused by the low mass transfer rate of protease in pelt. Here, the effects of protease dosage, common auxiliaries and molecular weight of protease on protease transfer during bating were investigated so that we can find the key points to avoid excessive collagen damage, particularly in the grain. Observably, increasing protease dosage led to faster protease transfer and softer leather, but along with more considerable grain damage. Using penetrating agent JFC (fatty alcohol-polyoxyethylene ether) and ammonium sulfate enhanced protease transfer and simultaneously alleviated collagen damage due to the decrease in interfacial tension and electrostatic attraction between protease and pelt, respectively. Additionally, proteases with lower molecular weight transferred faster in pelt, which suggests that a potential strategy to solve the conflict between the mass transfer and the reaction of protease in pelt might be to produce/employ smaller bating proteases. Note de contenu : - MATERIALS AND METHODS : Materials - Effect of protease dosage on bating performance - Effect of auxiliaries on bating performance of protease - Effect of molecular weight of protease on its transfer rate during bating - RESULTS AND DISCUSSION : The effect of protease dosage on bating performance - The effect of auxiliaries on bating performance - The effect of molecular weight of protease on its mass transfer rate during bating DOI : https://doi.org/10.1186/s42825-019-0007-7 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0007-7.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36949 [article]

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Fractionational and structural characterization of lignin and its modification as biosorbents for efficient removal of chromium from wastewater : a review / Bing Wang in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 25 p. Titre : Fractionational and structural characterization of lignin and its modification as biosorbents for efficient removal of chromium from wastewater : a review Type de document : texte imprimé Auteurs : Bing Wang, Auteur ; Yong-Chang Sun, Auteur ; Run-Cang Sun, Auteur Année de publication : 2019 Article en page(s) : 25 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Adsorption Caractérisation Cuirs et peaux -- Industrie -- Aspect de l'environnement Déchets industriels -- Elimination Eaux usées -- Epuration Eaux usées -- Teneur en chrome Extraction (chimie) Lignocellulose Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The removal of chromium (Cr) from wastewater by various adsorbents has been investigated. As compared with the commercial activated carbon, the biosorbents with inexpensive and high adsorption capacities are developed from lignocellulosic wastes. Lignin, existing in lignocellulosic biomass, is the second most abundant resource in nature. Recently, lignin-based bio-sorbents were served as an advanced novel material for the metal ions and dye adsorption from wastewater. It has showed several advantages in the wastewater treatments because of the low-cost, high adsorption capacity, easy recover, and possibility of metal recovery. In this review, the isolation of lignin from lignocellulosic biomass was summarized, and the structural characteristics of lignin were comparably analyzed. The modification of lignin was performed to obtain a large surface area, strong binding-site, and high and quick adsorption properties of lignin-based adsorption materials. The adsorption efficiency of Cr ions was found to be strongly dependent on the pH of the wastewater. To further illustrate the adsorption process, the structural changes and the interactions between the metal ions and the functional groups of the lignin-based biosorbents in the adsorption process should be further investigated. Once the cost-effective and high-efficiency modification techniques are developed, lignin-based adsorbents can be expected to be the most suitable alternatives for Cr ions removal from wastewater in industry. Note de contenu : - FRACTIONATION AND CHARACTERIZATION OF LIGNIN FROM LIGNOCELLULOSIC BIOMASS : Lignin extraction - Chemical composition and characterization of lignin - FTIR spectroscopy analysis - Thermogravimetric analysis - 1H-NMR spectra analysis - 31P NMR - Two-dimensional HSQC NMR technique - Lignin utilization - FUNCTIONAL GROUPS PRESENT INLIGNIN AND LIGNIN MODIFICATION : Functional groups present in lignin - Lignin modification - AN OVERVIEW OF THE LEATHER INDUSTRY : Cr removal from wastewater - Present disposal methods for the Cr (III)/Cr (VI) removal from wastewater - Lignocellulosic biomass and other non-living materials as biosorbents for the removal of Cr - CR REMOVAL FROM WASTEWATER BY USING LIGNIN-BASED BIOSORBENTS : Modification of lignin for Cr removal from wastewater - Lignin-based activated carbons production and Cr adsorption - Cr adsorption mechanisms - Table 1 Composition of cellulose, hemicelluloses, and lignin in various biomass - Table 2 Functional groups found in 100, C9 repeat units of lignin - Table 3 Cr adsorption by various biosorbents from lignocellulosic biomass and other materials DOI : https://doi.org/10.1186/s42825-019-0003-y En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0003-y.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36950 [article]

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Research progress on resource utilization of leather solid waste / Yanchun Li in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) Titre : Research progress on resource utilization of leather solid waste Type de document : texte imprimé Auteurs : Yanchun Li, Auteur ; Ruijun Guo, Auteur ; Wenhui Lu, Auteur ; Deyi Zhu, Auteur Année de publication : 2019 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Boues d'épuration -- Recyclage Cuirs et peaux -- Déchets -- Recyclage Tags : 'Déchets  solides  de  cuir'  cheveux  tannerie'  non  tannés'  cuir  contenant  du  chrome'  'Boues  fini' Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Leather making is the process of converting raw hides into leather. Amounts of solid waste containing hazardous and high value components are generated during this process. Therefore, the elimination of the potential pollution and resource utilization of leather solid waste are the primary research hotspots. Herein, we comprehensively review the recent advances in the resource utilization of leather solid waste generated from chrome tanning including the utilization of tannery hair waste, untanned solid waste, chrome-containing leather solid waste, tannery sludge and finished leather waste, emphasizing on the general and novel utilization approaches. Finally, the remaining challenges and perspectives were summarized, in order to accelerate the development of resource utilization of leather solid waste. Note de contenu : - RESOURCE UTILIZATION OF TANNERY HAIR WASTE : Extraction of keratin - Application of keratin - RESOURCE UTILIZATION OF UNTANNED SOLID WASTE : Preparation of collagen/gelatin - Application of collagen/gelatin - Utilization of grease waste residue - RESOURCE UTILIZATION OF CHROME-CONTAINING LEATHER SOLID ASTE : Direct resource utilization - Indirect resource utilization - RESOURCE UTILIZATION OF TANNERY SLUDGE : Biocomposting - Anaerobic digestion - Building materials - Preparation of oil and adsorbent - RESOURCE UTILIZATION OF FINISHED LEATHER WASTE - CONCLUSIONS AND PERSPECTIVES : The extraction and application of keratin - Untanned solid waste and chrome-containing leather solid waste - Tannery sludge - Finished leather waste DOI : https://doi.org/10.1186/s42825-019-0008-6 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0008-6.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36951 [article]

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Regenerating leather waste for flexible pressure sensing applications / Jie Lei in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 9 p. Titre : Regenerating leather waste for flexible pressure sensing applications Type de document : texte imprimé Auteurs : Jie Lei, Auteur ; Binghua Zou, Auteur ; Runan Zhang, Auteur ; Kang Zhang, Auteur ; Ruijie Xie, Auteur ; Weina Zhang, Auteur ; Jiansheng Wu, Auteur ; Li Sheng, Auteur ; Bing Zheng, Auteur ; Fengwei Huo, Auteur Année de publication : 2019 Article en page(s) : 9 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Capteurs de pression Caractérisation Collagène Couches minces Cuirs et peaux -- Déchets -- Recyclage Détecteurs de mouvement humain Matériaux filmogènes Reconnaissance vocale Souplesse (mécanique) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Pressure sensor can be applied in a wide range of fields, such as voice recognition, human motions detection and artificial electronic skin, the sensing of which is greatly influenced by the flexibility and stretchability of substrate materials. Here, based on the piezoresistive effect, new kinds of flexible pressure sensors have been realized from a pair of flexible and biocompatible collagen films: one is coated by silver nanowires (Ag NWs) and the other by interdigital electrode, respectively. The collagen films are regenerated from leather waste and could bring economic benefits to society. The prepared pressure sensors are applied for voice recognition and human motion detection. Note de contenu : - MAIN TEXT : Preparation and Properities of the flexible collagen film Preparation and performances of the flexible pressure sensor - Human physical motions sensing - Voice recognition sensing - EXPERIMENTAL SECTION : Preparation of the collagen films - Characterization of the collagen films - Fabrication of the flexible pressure sensor - Performances of the flexible pressure sensor DOI : https://doi.org/10.1186/s42825-019-0009-5 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0009-5.pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36952 [article]

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Collagen structure changes during chrome tanning in propylene carbonate / Yi Zhang in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 7 p. Titre : Collagen structure changes during chrome tanning in propylene carbonate Type de document : texte imprimé Auteurs : Yi Zhang, Auteur ; Jenna Kate Buchanan, Auteur ; Geoff Holmes, Auteur ; Bradley William Mansel, Auteur ; Sujay Prabakar, Auteur Année de publication : 2019 Article en page(s) : 7 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse thermique Carbonate de propylène Collagène -- Structure Cuirs et peaux Diffusion de la lumière aux petits angles Tannage au chrome Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Green solvents, such as propylene carbonate (PC), can be used in leather processing to improve the efficiency of chrome tanning and reduce wastewater. Here we report a combined small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) study on PC and its efficacy as a carrier medium during chrome tanning. SAXS analysis on the collagen structure of chrome tanned leather using PC, compared to conventionally tanned leather using water, showed an increase in Cr uptake in addition to the more uniform penetration of Cr through the leather cross-section. The increased binding of Cr to the collagen matrix drives the decreased hydration environment of the collagen triple helix. Furthermore, DSC studies show a uniform hydrothermal stability for the PC samples due to the more even distribution of Cr through the collagen matrix. Understanding the mechanisms by which chrome tanning occurs in non-aqueous solvents can guide us towards a more sustainable future for the leather industry. Note de contenu : - EXPERIMENTAL : Materials - Leather sample preparation - Small-angle X-ray scattering (SAXS) measurements - Differential scanning calorimetry (DSC) measurements - Percentage uptake of chromium - RESULTS AND DISCUSSION : Chromium uptake from AAS studies - SAXS peak changes with tanning - D-period changes through the leather cross-section - Changes in R6/5 - DSC studies DOI : https://doi.org/10.1186/s42825-019-0011-y En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0011-y.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36953 [article]

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Kinetics and mechanism of thermal degradation of vegetable-tanned leather fiber / Jie Liu in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 13 p. Titre : Kinetics and mechanism of thermal degradation of vegetable-tanned leather fiber Type de document : texte imprimé Auteurs : Jie Liu, Auteur ; Lan Luo, Auteur ; Yadi Hu, Auteur ; Fang Wang, Auteur ; Xuejing Zheng, Auteur ; Keyong Tang, Auteur Année de publication : 2019 Article en page(s) : 13 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cinétique chimique Cuir Énergie d'activation L'énergie d'activation est la quantité d'énergie nécessaire pour lancer un processus chimique, le plus souvent une réaction. En effet, pour démarrer un processus, on doit souvent faire face à une barrière énergétique (c’est-à-dire apporter un minimum d'énergie pour le démarrage). Cette quantité est exprimée, selon le système international d'unités, en kJ/mol (kilojoules par mole de réactif). Pyrolyse La pyrolyse est la décomposition ou thermolyse d'un composé organique par la chaleur pour obtenir d'autres produits (gaz et matière) qu'il ne contenait pas. L'opération est réalisée en l'absence d'oxygène ou en atmosphère pauvre en oxygène pour éviter l'oxydation et la combustion (L’opération ne produit donc pas de flamme). Il s'agit du premier stade de transformation thermique après la déshydratation. Elle permet généralement d'obtenir un solide carboné, une huile et un gaz. Elle débute à un niveau de température relativement bas (à partir de 200 °C) et se poursuit jusqu'à 1 000 °C environ. Selon la température, la proportion des trois composés résultants est différente. Tannage végétal Thermogravimétrie Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Thermal degradation of vegetable-tanned leather fiber (VLF) was investigated by thermogravimetric analysis aiming to know the exact kinetics and degradation mechanism. The thermogravimetric (TG) and differential thermogravimetric (DTG) curves showed that decomposition of the VLF occurs mainly in the range of 150–600 °C, and the latter exhibits asymmetrical peak with a pronounced shoulder. The decomposition process was first analyzed by deconvolution of the experimental DTG curves, followed by reconstruction of the weight loss profiles of two individual processes. Several common isoconversional approaches were applied to calculate the activation energy over a wide range of conversion for the sample, including modified Kissinger-Akahira-Sunose (MKAS), Friedman, and Flynn-Wall-Ozawa. The average activation energy of vegetable-tanned leather fiber was found to be 241.9 kJ mol− 1 by MKAS method. The activation energy values obtained for the pseudocomponents representing highly-crosslinked and low-crosslinked collagen in VLF were given as 190.6 and 124.8 kJ mol− 1, respectively. Generalized master plots results suggested that the reaction mechanism for highly-crosslinked collagen follows the random nucleation and growth process at conversion values lower than 0.5. When the conversion is higher than 0.5, the mechanism tends to random scission model. For low-crosslinked collagen, the degradation is mainly governed by random nucleation and nuclei growth. The gaseous products of VLF thermal degradation were analyzed with an online-coupled TG-Fourier transform infrared spectroscopy system. Note de contenu : - THEORETICAL BACKGROUND : Kinetic methods - Iso-conversional method - Generalized master plots method - EXPERIMENTAL : Materials - Thermogravimetric analysis - RESULTS AND DISCUSSION: The overall TG/DTG curves - Kinetic analysis - Determination of degradation mechanism - FTIR analysis of gaseous products from the pyrolysis of VLF DOI : https://doi.org/10.1186/s42825-019-0010-z En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0010-z.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36954 [article]

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Quantitative and structural analysis of isotopically labelled natural crosslinks in type I skin collagen using LC-HRMS and SANS / Yi Zhang in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 9 p. Titre : Quantitative and structural analysis of isotopically labelled natural crosslinks in type I skin collagen using LC-HRMS and SANS Type de document : texte imprimé Auteurs : Yi Zhang, Auteur ; Rafea Naffa, Auteur ; Christopher J. Garvey, Auteur ; Catherine Maidment, Auteur ; Sujay Prabakar, Auteur Année de publication : 2019 Article en page(s) : 9 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse quantitative (chimie) Chromatographie en phase liquide Collagène -- Structure Cuirs et peaux Réticulation (polymérisation) Spectrométrie de masse Traceurs radioactifs Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Collagen structure in biological tissues imparts its intrinsic physical properties by the formation of several covalent crosslinks. For the first time, two major crosslinks in the skin dihydroxylysinonorleucine (HLNL) and histidinohydroxymerodesmosine (HHMD), were isotopically labelled and then analysed by liquid-chromatography high-resolution accurate-mass mass spectrometry (LC-HRMS) and small-angle neutron scattering (SANS). The isotopic labelling followed by LC-HRMS confirmed the presence of one imino group in both HLNL and HHMD, making them more susceptible to degrade at low pH. The structural changes in collagen due to extreme changes in the pH and chrome tanning were highlighted by the SANS contrast variation between isotopic labelled and unlabelled crosslinks. This provided a better understanding of the interaction of natural crosslinks with the chromium sulphate in collagen suggesting that the development of a benign crosslinking method can help retain the intrinsic physical properties of the leather. This analytical method can also be applied to study artificial crosslinking in other collagenous tissues for biomedical applications. Note de contenu : - EXPERIMENTAL METHODS : Materials and methods - RESULTS AND DISCUSSION : Characterization of natural crosslinks in skin collagen : isotopic labelling using NaBD4 and mechanism of HHMD formation - Quantification of natural crosslinks in skin collagen : relationship with pH and crosslinking conditions - Structural analysis of skin collagen : interplay between natural and artificial crosslinks - Table 1 : Collagen D-periodicity at different processing stages in control, reduced and labelled skin samples. The D-period decreased for all samples starting from raw to the pickled stage, then increased at the crosslinked stage DOI : https://doi.org/10.1186/s42825-019-0012-x En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0012-x.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36955 [article]

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