Analyzing the mechanism and effect of acid protease in wet blue bating process for leather production / Hao Li in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 1 (01/2020)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXV, N° 1 (01/2020) . - p. 10-15 Titre : Analyzing the mechanism and effect of acid protease in wet blue bating process for leather production Type de document : texte imprimé Auteurs : Hao Li, Auteur ; Jinzhi Song, Auteur ; Deyi Zhu, Auteur ; Yanchun Li, Auteur ; Shan Cao, Auteur ; Jing Xiao, Auteur Année de publication : 2020 Article en page(s) : p. 10-15 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Biodégradation Chrome Collagène -- Détérioration 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 -- Propriétés physiques Desmosine La desmosine est une structure moléculaire formée par l'association de quatre chaînes latérales de lysine. On la retrouve associée à l'élastine où elle forme des interconnexions (liaisons covalentes) entre les différentes fibres et participe ainsi à ses propriétés mécaniques. (Wikipedia) Elastine -- Détérioration Enzymes microbiennes Hydroxyproline Peptidases Résistance chimique Wet-blue (tannage) Peau tannée au chrome (le chrome donne une couleur bleue) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In recent years, in order to reduce the pollution produced in beamhouse and tanning sections, more and more tanneries purchase wet blue from other factories in other regions directly used as raw materials for finished leather production thereby those polluted preliminary steps can be eliminated. Therefore, the wet blue bating process is an essential step to minimize the differences of wet blue which are purchased from different regions. In this study, the properties of different acid protease are analyzed for selecting suitable protease used for wet blue bating. The analysis of chromium tolerance of different acid proteases reveals that, Ll and L4 produced from Aspergillus have higher chromium resistance than that of produced from Bacillus. The effect of Ll and L4 on wet blue and collagen shows that the Ll has more excellent performance, in which the molecular weight of functional protein is 48 KD. By SEM and MCT analysis, Ll can successfully disperse the collagen fibers of wet blue. Furthermore, the biodegradation rates of collagen and elastin were 0.006‰ and 0.5‰, respectively. It indicates that the acid protease mainly degraded elastin but not collagen in bating process thereby ensuring production safety. This paper provides the importance references for the application and the basis for the development of mechanism of acid protease in bating process. Note de contenu : - EXPERIMENTAL : Materials - determination of chromium tolerance of acid proteases - Pretreatment of wet blue - Physical properties evaluation - Circular dichroism spectrometer analysis - Micro-structure observation - SDS-PAGE analysis - Preparation of enzymatic hydrolysate - Determination of hydroxyproline by HPLC method - Determination of desmosine in the hydrolysate by ELISA method - Calculating the biodegradation rate of collagen and elastin - RESULTS AND DISCUSSION : Chromuim tolerance evaluation - Physical properties analysis - Effect of L1 and L4 acid protease act on collagen - Enzymatic properties of L1 acid protease - Observation of the porosity or dispersion of collagen fiber (bundle) - Analyze the biodegradation rate of L1 to structural protein in wet blue DOI : https://doi.org/10.34314/jalca.v115i1.1463 En ligne : https://drive.google.com/file/d/12pIVNJ4YE3q10psriwZc0l0bZLz6G4M7/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33392 [article]

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High performance leather based on in situ formation of reduced graphene oxide in chrome tanning / Xinle Yang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVII, N° 5 (05/2022)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVII, N° 5 (05/2022) . - p. 206-211 Titre : High performance leather based on in situ formation of reduced graphene oxide in chrome tanning Type de document : texte imprimé Auteurs : Xinle Yang, Auteur ; Yanchun Li, Auteur ; Mao Yang, Auteur ; Xugang Dang, Auteur ; Shan Cao, Auteur Année de publication : 2022 Article en page(s) : p. 206-211 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Caractérisation Cuirs et peaux Cuirs et peaux -- Propriétés mécaniques Matériaux hautes performances Oxyde de graphène Tannage au chrome Température de retrait Thermocinétique Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : A novel method of high performance leather prepared via in situ reduction of graphene oxide after tanning was proposed in this research. First, nano-graphene oxide (GO) was prepared by an improved Hummers method. Then, the prepared GO was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Finally, GO was added during the chrome tanning process, and GO was reduced by ascorbic acid after the chrome tanning was completed. Moreover, the shrinkage temperature, tensile strength, tear strength and thermal conductivity of the finished leather were investigated. The results showed that the absorption of chrome tanning agent was significantly improved by the addition of GO. The tensile strength, tear strength, and the thermal conductivity of the resulted leather obviously surpassed the leather tanned by chrome tanning agent. Specifically, the tensile strength and tear strength of the leather reached 21.25 MPa and 163.95 N·mm-1 , respectively, when the amount of reducing agent was ten times the amount of GO. A combination of the tanning of leather and the in situ reduction of GO is expected to become a new processing method for preparation of high performance. Note de contenu : - EXPERIMENTAL : Materials and chemicals - Preparatio of GO - Tanning process - Reduction of GO - Characterization - Physicochemical properties of leather - RESULTS AND DISCUSSION : Infrared analysis of GO - XRD analysis of GO - Morphology analysis - XPS analysis of GO - Physical - mechanical properties testing of leather - Thermal conductivity testing of leather - Table 1 : Experimental scheme for in-situ reduction of GO - Table 2 : Chemical composition of grpahite and GO - Table 3 : Physical - mechanical properties of leather DOI : https://doi.org/10.34314/jalca.v117i5.4917 En ligne : https://drive.google.com/file/d/19dT_nj0m_Vl53ZtahY9OQbpl-TY3vzkU/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37571 [article]

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NH4HCO3 as additive for fabrication of thin film nanocomposite membrane with enhanced permeability / Yanchun Li in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 21, N° 1 (01/2024)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 21, N° 1 (01/2024) . - p. 413-421 Titre : NH4HCO3 as additive for fabrication of thin film nanocomposite membrane with enhanced permeability Type de document : texte imprimé Auteurs : Yanchun Li, Auteur ; Shilin Zhou, Auteur ; Jin He, Auteur ; Yuwen Lai, Auteur ; Wentao Yan, Auteur ; Yong Zhou, Auteur ; Congjie Gao, Auteur Année de publication : 2024 Article en page(s) : p. 413-421 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Caractérisation Couches minces Membranes (technologie) Moussants Nanobulles Nanofiltration Index. décimale : 667.9 Revêtements et enduits Résumé : During interfacial polymerization, the in situ growth of nanobubbles can exist between the support layer and the separation layer of the membrane, which changes the microstructure of the membrane and improves its performance. The incorporation of R812s SiO2 in the preparation of the mixed matrix nanofiltration membrane increases the surface interface pores, thereby improving the flux. In this study, NH4HCO3 foaming agent was introduced into the aqueous phase of the R812s SiO2 nanofiltration membrane to react with the byproduct HCl generated during the interface process, thus generating nanobubbles that exist between the support layer and the separation layer. The surface of the membrane was characterized by related instruments. It was found that the addition of NH4HCO3 generates a large number of nanobubbles, causing significant changes to the membrane surface, and resulting in increased protrusions and pore size, greatly improving membrane flux while slightly reducing the rejection of sodium sulfate. Note de contenu : - EXPERIMENTAL : Materials and chemicals - Membrane preparation - Characterization of membranes - Testing of separation performances - RESULTS AND DISCUSSION : Influence of the NH 4 HCO 3 concentration - Optimization of reaction monomer - Optimization of TMC monomer - Optimization of PIP monomer - Table 1 : Specific preparation parameters of TFN membrane DOI : https://doi.org/10.1007/s11998-023-00834-y En ligne : https://drive.google.com/file/d/1fSntPfrbgUJxHftnPQaEUd-NYC_LC0hS/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40462 [article]

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Polyurethane electrospun fiber biomimetics membrane for constructing the structure of grain layer with good breathability for cattle split leather / Nan Chen in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVI, N° 8 (08/2021)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVI, N° 8 (08/2021) . - p. 284-289 Titre : Polyurethane electrospun fiber biomimetics membrane for constructing the structure of grain layer with good breathability for cattle split leather Type de document : texte imprimé Auteurs : Nan Chen, Auteur ; Yanchun Li, Auteur ; Jianbo Qu, Auteur ; Jian-Yong Wang, Auteur Année de publication : 2021 Article en page(s) : p. 284-289 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Air Caractérisation Chimie biomimétique Cuir Electrofilature Essais accélérés (technologie) Membranes imper-respirantes Mousses plastiques Perméabilité Polyuréthanes Tissés Vapeur d'eau Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The traditional thick coating on split leather does not have the ability to breathe like full grain leather. The air and water vapor permeabilities of full grain leather are well known properties due to its fiber woven structure. Simulating the fiber morphology and weaving structure of the dermis or grain layer is very important to construct a top surface layer for split leather. In this paper, a PU (polyurethane) foam layer is put first on the split to enhance the adhesion of a second application of a superfine fibrous PU resin. This foam uses well-known waterborne polyurethane foaming technology. This dried foam has good breathability because of high porosity. A superfine fiber membrane is next put atop of the foam layer by using an electro-spun polyurethane resin. This second resin imitates collagen fibers in the network structure of the leathers’ grain layer. Thus, this resultant electrospun fiber biomimetics membrane simulated the grain layer of natural leather. SEM showed the morphology and structure of this electrospun fiber biomimetic membrane to be like that of the grain layer of natural leather. The porosity and apparent density were basically the same as the grain of leather, which were 63.65% and 583.878 kg/m3 respectively. The air and water vapor permeability of the biomimetics membrane were also as high as 2250 mL·cm-2·h-1 and 8753.02 μg·cm-2·h-1 respectively. Therefore, the biomimetics membrane largely restored the ability to breathe of split leather. Thus, this method simulates the performance and structure of full grain leather and is a novel method for industrial production. Note de contenu : - EXPERIMENTAL : Materials and instruments - Preparation of the biomimetics electrospun fiber coating - CHARACTERIZATION : Morphology observation - Porosity and apparent density analyses - Air permeability and water vapor permeability analyses - RESULTS AND DISCUSSION : SEM observation of the surface and longitudinal of the sample - Test for air permeability and water vapor permeability DOI : https://doi.org/10.34314/jalca.v116i8.4358 En ligne : https://drive.google.com/file/d/1YepXdwsWoigjZKA57PKF4GCbf594UtuZ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36085 [article]

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Preparation of amino-terminated hyperbranched buffing dust and its adsorption property towards acid fuchsin : Use of an industry by-product to adsorb dyestuffs / Jie Liu in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 105, N° 1 (01-02/2021)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 105, N° 1 (01-02/2021) . - p. 31-40 Titre : Preparation of amino-terminated hyperbranched buffing dust and its adsorption property towards acid fuchsin : Use of an industry by-product to adsorb dyestuffs Type de document : texte imprimé Auteurs : Jie Liu, Auteur ; Zhang Feifei, Auteur ; Yinghu Song, Auteur ; Zhendi An, Auteur ; Yanchun Li, Auteur Année de publication : 2021 Article en page(s) : p. 31-40 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse quantitative (chimie) Caractérisation Colorants -- Adsorption Cuirs et peaux -- Déchets -- Recyclage Eaux usées -- Epuration Electrostatique Fuchsine, Acide Isotherme d'adsorption Poids moléculaires Polymères ramifiés Poussière de cuir Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Buffing dust (BD) is generated in the buffing process of leather making. Amino-terminated hyperbranched polymer (HBPN) was used to modify the BD to prepare hyperbranched polymer modified BD (HBPN-B). The molecular weight of HBPN was analysed by GPC and FTIR, SEM-EDS and BET analysis were employed to characterise the structure of the HBPN-B. The BET specific surface area of HBPN-B was 7.128m2.g-1. The EDS analysis results show that after modification, the N content of BD increased from 21.23% to 24.47%. HBPN-B was then used in the adsorption of dye from wastewater. The influences of reaction conditions on the adsorption properties of HBPN-B towards acid fuchsin were studied and the adsorption kinetic and isotherm were researched. The removal rate of acid fuchsin by HBPN-B increased with the increase of pH, the removal rate reached the maximum at pH2.5. Electrostatic attraction was the chief adsorption mechanism. The removal rate increased with the increase of HBPN-B dosage and temperature. The adsorption process was in conformity with pseudo-second order kinetic and Langmuir adsorption isotherm model adsorption. Note de contenu : - MATERIALS AND METHODS : Chemicals - Preparation of HBPN-B - The characterisation of HBPN-B - Quantification of acid fuchsin - Batch adsorption experiments - Adsorption kinetic - Adsorption isotherm - RESULTS AND DISCUSSION : Characterisation of the HBPN-B - Effect of conditions of solution to the adsorption property of HBPN-B - Kinetics adsorption studies - Adsorption isotherm - Table 1 : GPC analysis result of HBPN - Table 2 : BET characterisation of biosorbent - Table 3 : Constants for the kinetic models of acid fuchsin on the HBPN-B - Table 4 : Isotherm parameters obtained from the fitting to experimental results on the adsorption of acid fuchsin onto the HBPN-B En ligne : https://drive.google.com/file/d/1HBFOgdQ3CcXaP5KEwrSo-QjLF-JlWCTB/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35315 [article]

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Quantitative analysis of FITC-trypsin distribution in goatskin matrix / Xuesong Li in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIV, N° 4 (04/2019)  

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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)  

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