Achieving constant pressure and delay in leather thickness measurement / Duo Ning in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 96, N° 2 (03-04/2012)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 96, N° 2 (03-04/2012) . - p. 60-63 Titre : Achieving constant pressure and delay in leather thickness measurement Type de document : texte imprimé Auteurs : Duo Ning, Auteur ; Lei Zhang, Auteur ; Xin Dengke, Auteur ; Wang Panpan, Auteur ; Meng Hui, Auteur Année de publication : 2012 Article en page(s) : p. 60-63 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux Epaisseur -- Mesure Logiciels Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The International standard defines leather thickness to be value recorded 5 seconds after the start of the measurement under a constant pressure of 500g/cm2. We have developed specialized computer software to achieve the 5-second delay and constant pressure thus avoiding human errors in practice. Our software can accurately determine the starting time of the measurement and lock the valid data point automatically. By using the software in our digital leather thickness measuring device with independent intellectual property rights, we are able to measure the leather thickness in a completely automatic fashion for the first time. We report satisfactory experiment results. Furthermore, our device is portable and can be used in any production situation. Note de contenu : - RESEARCH BACKGROUND - SOLUTIONS : Achieving required sample pressure - Achieving 5 seconds' delay - ACHIEVING REQUIRED SAMPLE PRESSURE IN ALL DIRECTIONS En ligne : https://drive.google.com/file/d/1OOkm567We_JxTxxy_faUyPvOsUcgwEnG/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=14569 [article]

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Application of Y-shaped polyurethane and polyacrylic acid as a complex retanning agent in aldehyde-tanned goat leather / Shuangquan Lai in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXII, N° 11 (11/2017)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXII, N° 11 (11/2017) . - p. 367-376 Titre : Application of Y-shaped polyurethane and polyacrylic acid as a complex retanning agent in aldehyde-tanned goat leather Type de document : texte imprimé Auteurs : Shuangquan Lai, Auteur ; Yong Jin, Auteur ; Hanping Li, Auteur ; Lei Zhang, Auteur ; Xin Yin, Auteur Année de publication : 2017 Article en page(s) : p. 367-376 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Acide polyacrylique Copolymères -- Synthèse Copolymères séquencés Cuirs et peaux -- Analyse Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés organoleptiques Cuirs et peaux -- Propriétés physiques Cuirs et peaux de chèvres Glutaraldéhyde Morphologie (matériaux) Polymères amphiphiles Polyuréthanes Retannage Tannage organique Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : A kind of Y-shaped amphiphilic block polyurethane copolymers (PUGs) with different molecular weights were successfully synthesized to be used as retanning agent combined with polyacrylic acid (PAA) for modified glutaraldehyde tanned goatskin. The structures of resulting products were characterized by FTIR, and the molecular weights of products were measured with GPC. The application performances were investigated by measuring the organoleptic and physical mechanical properties of resulting leathers according to the alone or combined use of PUG and PAA, the molecular weight of PUG, and the offer percentage of retanning agent. The best performance was found in the leather retanned by PUG750 and PAA complex retanning agent at the total offer percentage of 4 wt%. Finally, the free formaldehyde contents in the leathers retanned with 4 wt% PUG750 and PAA at different pH conditions were analyzed with acetyl acetone colorimetric method. The mechanical properties as well as the fibers morphologies of the experimental and control groups were also investigated. The results demonstrated that when the pH value at the later stage of retanning process was controlled at 4.0 or 3.0, the free formaldehyde content was significantly reduced by 20.3% or 38% respectively ; and the physical mechanical properties of leathers were also very excellent to meet the performance requirements of goatskin garment leathers. According to these results, the method for using PUG and PAA as a complex retanning agent might be a good choice in chrome-free tanning process. Note de contenu : - MATERIALS AND METHODS : Materials - Synthesis of Y-shaped amphiphilic block polyurethane copolymers (PUGs) - Synthesis of polyacrylic acid (PAA) - Fourier Transform Infrared Spectra (FTIR) - Gel permeation chromatography (GPC) - Application of polyurethanes and polyacrylic acid - Analysis of leather properties - Scanning electron microscopy analysis - Determination of free formaldehyde contents in leathers - RESULTS AND DISCUSSION : Synthesis of polyurethane copolymers and polyacrylic acid - Effect of different retanning agents on the organoleptic and physical properties of leathers - Effect of the molecular weight of PUG on the organoleptic and physical properties of leathers - Effect of the amount of complex retanning agent on the organoleptic and physical properties of leathers - Application of the complex retanning agent under different pH conditions En ligne : https://drive.google.com/file/d/1n0hhgDSLoOspbiCVezGLJhDkXewQevzZ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29395 [article]

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Corrosion-resistant composite coatings based on a graphene oxide–metal oxide/urushiol formaldehyde polymer system / Lei Zhang in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 18, N° 5 (09/2021)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 18, N° 5 (09/2021) . - p. 1209-1225 Titre : Corrosion-resistant composite coatings based on a graphene oxide–metal oxide/urushiol formaldehyde polymer system Type de document : texte imprimé Auteurs : Lei Zhang, Auteur ; Wupin Wang, Auteur ; Haitang Wu, Auteur ; Zeyu Zheng, Auteur ; Ming Wei, Auteur ; Xiaohua Huang, Auteur Année de publication : 2021 Article en page(s) : p. 1209-1225 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Anticorrosifs Anticorrosion Bases (chimie) Copolymère urushiol formaldéhyde Dioxyde de titane Métaux -- Revêtements protecteurs Oxyde d'yttrium Oxyde de graphène Résistance chimique Revêtements organiques Silice La silice est la forme naturelle du dioxyde de silicium (SiO2) qui entre dans la composition de nombreux minéraux. La silice existe à l'état libre sous différentes formes cristallines ou amorphes et à l'état combiné dans les silicates, les groupes SiO2 étant alors liés à d'autres atomes (Al : Aluminium, Fe : Fer, Mg : Magnésium, Ca : Calcium, Na : Sodium, K : Potassium...). Les silicates sont les constituants principaux du manteau et de l'écorce terrestre. La silice libre est également très abondante dans la nature, sous forme de quartz, de calcédoine et de terre de diatomée. La silice représente 60,6 % de la masse de la croûte terrestre continentale. Index. décimale : 667.9 Revêtements et enduits Résumé : Composite coatings were fabricated based on a graphene oxide–metal oxide/urushiol formaldehyde polymer (GO–TiO2/UFP, GO–SiO2/UFP and GO–Y2O3/UFP) system with modifications, and its effectiveness in corrosion protection of metal substrates was demonstrated. First, a GO–TiO2 composite was synthesized using titanium dioxide loading on GO via 3-aminopropyltriethoxysilane (APTES). The GO–Y2O3 composite was synthesized using nano-yttrium oxide intercalating into GO through two different silane coupling agents. The GO–SiO2 composite was synthesized via an in-situ two-step sol-gel process utilizing APTES and tetraethylorthosilicate (TEOS) in an aqueous ethanol solution. The morphology and structure of the GO–metal oxide composites (GO–TiO2, GO–Y2O3 and GO–SiO2) were studied. Subsequently, GO–metal oxides were incorporated into UFP to investigate the composite’s effectiveness in corrosion protection of metal substrates. Compared with GO–TiO2/UFP and GO–Y2O3/UFP, GO–SiO2/UFP showed superior alkali-resistance enhancing performance. Additionally, GO crosslinked with APTES–TiO2 via covalent bonds and the well-dispersed GO–TiO2 in UFP improved the electrochemical corrosion properties of the UFP coatings, most likely due to the obstruction of the diffusion pathways inside the UFP coating matrix, thus preventing the diffusion of penetrating species. It was revealed that the corrosion resistance of GO–TiO2/UFP composite coating was noticeably higher than GO–SiO2/UFP and GO–Y2O3/UFP composite coatings. Note de contenu : - MATERIALS AND METHODS : Materials - Fabrication process of the composite coatings - Characterization of composite coatings - Analysis of chemical resistance properties - RESULTS AND DISCUSSION : FTIR analysis - Microstructure and chemical composition of GO–metal oxide in UFP - XRD analysis - XPS analysis - Electrochemical tests - Chemical resistance of the UFP composite coatings - Corrosion protection mechanism - Table 1 : The XPS results for the GO–TiO2, GO–Y2O3 and GO–SiO2 sample - Table 2 : Electrochemical parameters obtained from the polarization curves of the UFP coatings containing different contents of GO–TiO2, GO–Y2O3, GO–SiO2 and MGO - Table 3 : Electrochemical parameters obtained from the EIS spactra of the UFP coatings containing different contents of GO–TiO2, GO–Y2O3 and GO–SiO2 - Table 4 : Resistance of the GO–TiO2/UFP, GO–Y2O3/UFP and GO–SiO2/UFP composite coatings against chemical attack after immersion in 30% H2SO4, 10% NaOH and 3% NaCl solution at room temperature DOI : https://doi.org/10.1007/s11998-021-00480-2 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-021-00480-2.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36426 [article]

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Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process / Yang Dongjiang in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 3, N° 2 (04/2006)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 3, N° 2 (04/2006) . - p. 127-131 Titre : Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process Type de document : texte imprimé Auteurs : Yang Dongjiang, Auteur ; Yao Xu, Auteur ; Lei Zhang, Auteur ; Shangru Zhai, Auteur ; Dong Wu, Auteur ; Yuhan Sun, Auteur Année de publication : 2006 Article en page(s) : p. 127-131 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Fourier, Spectroscopie infrarouge à transformée de Organosilanes Polysilsesquioxane Réflexion totale atténuée Résistance à l'humidité Résonance magnétique nucléaire Silice La silice est la forme naturelle du dioxyde de silicium (SiO2) qui entre dans la composition de nombreux minéraux. La silice existe à l'état libre sous différentes formes cristallines ou amorphes et à l'état combiné dans les silicates, les groupes SiO2 étant alors liés à d'autres atomes (Al : Aluminium, Fe : Fer, Mg : Magnésium, Ca : Calcium, Na : Sodium, K : Potassium...). Les silicates sont les constituants principaux du manteau et de l'écorce terrestre. La silice libre est également très abondante dans la nature, sous forme de quartz, de calcédoine et de terre de diatomée. La silice représente 60,6 % de la masse de la croûte terrestre continentale. Sol-gel, Procédé Spectroscopie d'absorption atomique Spectroscopie ultraviolette Index. décimale : 667.9 Revêtements et enduits Résumé : A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by 1H MAS NMR. For direct comparison purposes, an SiO2 coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N2 absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals. DOI : 10.1007/s11998-006-0015-4 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-006-0015-4.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3703 [article]

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Homogeneous dispersion of cellulose/graphite oxide nanofibers in water-based urushiol coatings with improved mechanical properties and corrosion resistance / Lei Zhang in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 20, N° 5 (09/2023)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 20, N° 5 (09/2023) . - p. 1649-1660 Titre : Homogeneous dispersion of cellulose/graphite oxide nanofibers in water-based urushiol coatings with improved mechanical properties and corrosion resistance Type de document : texte imprimé Auteurs : Lei Zhang, Auteur ; Haitang Wu, Auteur ; Chonglin Zhao, Auteur ; Lingce Kong, Auteur ; Xiaohua Huang, Auteur Année de publication : 2023 Article en page(s) : p. 1649-1660 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Anticorrosifs Anticorrosion Caractérisation Cellulose La cellulose est un glucide constitué d'une chaîne linéaire de molécules de D-Glucose (entre 200 et 14 000) et principal constituant des végétaux et en particulier de la paroi de leurs cellules. Greffage (chimie) Matériaux hybrides Nanofibres Oxyde de graphène Revêtements -- Propriétés mécaniques Revêtements en phase aqueuse Revêtements organiques Urushiol L’urushiol est une toxine organique que l'on trouve dans les plantes de la famille des Anacardiaceae, spécialement dans le genre Toxicodendron (par exemple le sumac grimpant en Amérique du Nord). Il provoque des allergies de la peau ou dermatites, pouvant être importantes, au contact de ces plantes. Le nom vient du mot japonais urushi (漆?), qui désigne une laque produite dans l'Asie orientale à partir du suc des arbres kiurushi (arbre à laque). L'oxydation et la polymérisation de l'urushiol dans le suc de l'arbre en présence d'humidité permet de former une laque dure utilisée traditionnellement pour produire des objets d'art laqués en Chine et au Japon. Index. décimale : 667.9 Revêtements et enduits Résumé : A polymeric coating based on a reactive urushiol-based polymeric emulsion was synthesized by grafting cellulose nanofibers (CNF) and graphene oxide (GO) onto the urushiol backbone, followed by phase inversion to obtain a cellulose nanofiber-graphene oxide/water-based urushiol emulsion (GO-CNF/WU). Following silane treatment (APTES), well-dispersed CNF-GO composites were obtained due to molecular interactions at the interface (including covalent, π-π and hydrogen bonding) between CNF and GO, resulting in a WU polymer which served as a mixing matrix to stabilize and improve the resulting GO-CNF through chemical-crosslinking. As expected, the mechanical properties (hardness and adhesion) and anticorrosion protection of the WU films were improved considerably after incorporating GO-CNF composites at fairly low concentrations. Compared to the WU film, the coated tinplate with the GO-CNF/WU coating displayed higher anticorrosion efficiency, with a PE of 99%. In addition, the pencil hardness of the GO-CNF/WU coatings increased significantly, from 2 to 6H, and adhesion was remarkably enhanced from grade 6 to 1 after the addition of 10% MGO to the films. Due to the synergistic protective effect of CNF and GO, the method may represent a facile and environmentally friendly approach to integrate multi-nanoscale blocks into WU polymer with excellent mechanical properties and corrosion resistance. Note de contenu : - MATERIALS AND METHODS : Materials - Preparation of GO-CNF suspensions - Preparation of the water-based O/W urushiol emulsion - Film preparation - Characterization of the GO-CNF/WU composite coating - RESULTS AND DISCUSSION : FTIR characterization - XRD characterization - XPS analysis - Micromorphology of WU films - Electrochemical behavior - Mechanical properties - Table 1 : Atomic concentrations and relative carbon composition of samples - Table 2 : Impedance measurements and protection efficiencies of WU coatings containing GO and CNF in 3.5% NaCl at 25°C - Table 3 : Mechanical properties of pure WU, GO/WU, CNF/WU and GO-CNF/WU composite coatings DOI : https://doi.org/10.1007/s11998-023-00770-x En ligne : https://link.springer.com/content/pdf/10.1007/s11998-023-00770-x.pdf?pdf=button% [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39978 [article]

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Preparation, characterization, and properties of graphene oxide/urushiol-formaldehyde polymer composite coating / Lei Zhang in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 15, N° 6 (11/2018)  

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