Application of carboxyl-functionalized epoxy resin in the leather tanning process / Bin Lyu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIII, N° 7 (07/2018)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIII, N° 7 (07/2018) . - p. 225-231 Titre : Application of carboxyl-functionalized epoxy resin in the leather tanning process Type de document : texte imprimé Auteurs : Bin Lyu, Auteur ; Li Yajuan, Auteur ; Dangge Gao, Auteur ; Jianzhong Ma, Auteur ; Lv Leihong, Auteur Année de publication : 2018 Article en page(s) : p. 225-231 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuir -- Teneur en chrome hexavalent Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés physiques Détérioration enzymatique Douceur (toucher) Eaux usées -- Teneur en chrome hexavalent Epoxydes Groupement carboxyle Polymères -- Synthèse Réactions chimiques Stabilité hydrothermale Tannage Température de retrait Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Chrome tanning is widely used in the tanning process ; however, it can cause environmental pollution. Leather tanned with epoxy resin was considered as a more environmentally friendlyprocess, but it takes as long as five days for reaction, and results in poor performance of leather. The aim of the present study was to tan leather collagen with a carboxyl-functionalized epoxy resin, which was thought to be an eco-friendly tanning process and the reaction time was shortened to 12h. The reaction between carboxyl-functionalized epoxy resin and leather collagen can be divided into two stages, the reaction of epoxy group with leather collagen and the reaction of carboxyl group with leather collagen. The influences of tanning conditions (medium pH, epoxy resin amount and reaction time) on the properties of tanned leather were also discussed. In the first stage, the epoxy group was reacted with leather collagen in basic conditions. The results showed that the carboxyl-functionalized epoxy resin could better penetrate into the leather fibers when the pH value was 8.5, and the best effect of tanned leather collagen was found using reaction condition of pH 7.0. In the second stage, it was the reaction of carboxyl group to leather collagen in acid conditions, and the best effect was found under the condition of pH was 3.5. Meanwhile, it provided a better tanning effect when the carboxyl-functionalized epoxy resin amount was 6% and the reaction time was 12h. The chrome-less tanning process that carboxyl-functionalized epoxy resin combination with 3% chrome was studied. The results showed that the hydrothermal stability and strength properties of leather tanned by carboxyl-functionalized epoxy resin with 3% chrome were close, even superior, to those of the leather produced by conventional chrome tanning with 8% chrome. Note de contenu : - MATERIALS AND METHODS : - Material - Methods : Synthesis of the carboxyl-functionalized epoxy resin - Tanning methodology - Testing and characterization : Shrinkage temperature - Thickness increment ratio - Mechanical properties - Softness - Enzymatic degradation - Chrome content in leather and waste water - Calculation - RESULTS : - Tanning conditions of carboxyl-functionalized epoxy resin pH : The amount of tanning agent - Chrome-less tanning results : SEM topography of the leather - Physical properties - Mechanical properties - Softness - Enzymatic degradation - Chrome content in leather and waste water En ligne : https://drive.google.com/file/d/1zAn7Cgd6nhD2xonUrhpGkK5uE09EybTG/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30830 [article]

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Diffusion and reaction behavior of proteases in cattle hide matrix via FITC labeled proteases / Jianzhong Ma in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIX, N° 5 (05/2014)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIX, N° 5 (05/2014) . - p. 138-145 Titre : Diffusion and reaction behavior of proteases in cattle hide matrix via FITC labeled proteases Type de document : texte imprimé Auteurs : Jianzhong Ma, Auteur ; Xueyan Hou, Auteur ; Dangge Gao, Auteur ; Jing Zhang, Auteur Année de publication : 2014 Article en page(s) : p. 138-145 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Collagène -- Détérioration Cuirs et peaux de bovins Diffusion (physique) Hydrolyse enzymatique Isothiocyanate de fluorescéine L'isothiocyanate de fluorescéine (FITC, fluorescein isothiocyanate en anglais) est un dérivé de la fluorescéine utilisée dans un large spectre d'applications comme la cytométrie en flux. Le FITC est une molécule de fluorescéine fonctionnalisée avec un groupe réactif isothiocyanate (-N=C=S), remplaçant un atome d'hydrogène sur le cycle le plus bas de la structure. Ce dérivé réagit avec les nucléophiles comme les groupes amines et sulfhydryles des protéines. Un groupe fonctionnel succinimidyle-ester greffé au noyau fluorescéine, créant le NHS-fluorescéine, forme un autre dérivé commun réagissant avec les amines, possédant une plus grande spécificité envers les amines primaires en présence d'autres nucléophiles. Le FITC possède un pic d'excitation et d'émission à 495 nm et 521 nm respectivement. Comme la plupart des fluorochromes, il est sujet au photobleaching. Par conséquent, des dérivés de la fluorescéine tels que l'Alexa 488 et le DyLight 488 ont été optimisés pour des applications chimiques et biologiques nécessitant une plus grande photostabilité, une plus grande intensité de fluorescence ou l'ajout de groupements différents. Peptidases Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Enzymes play an important role in the biological treatment of animal skin collagen in the leather making process. In this work, three proteases (2709, LimeG and SoakL) with different molecular weight were used in the treatment of cattle hide. Protein and hydroxyproline absorbance was measured to evaluate the treatment effectively. Proteases labeled by Fluorescein Isothiocyanate (FITC) were used to treat the cattle hide to observe the diffusion and reaction behavior of proteases in cattle hide matrix. The results indicate that when the cattle hide was treated with smaller molecular weight protease, the degradation degree of the protein and collagen was more than that of the cattle hide treated with larger molecular weight protease. The fluorescence microscopy images demonstrate that during the early stages, proteases chiefly diffused into the cattle hide matrix through pores and hair follicles, and then diffused into the inner layer via hair follicles to hydrolyze inter-fibrillary proteins for opening up collagen fibers. In the present investigation, a visible assessment for the diffusion and reaction behavior of proteases in the enzymatic treatment of cattle hide matrix was reported. Note de contenu : - MATERIALS AND METHODS : Materials - Instrumentation - Determination of the protease activity - Enzymatic treatment of cattle hide matrix - FITC labeled protease - Analysis - RESULTS AND DISCUSSION : Enzymatic treatment of cattle hide matrix - The effect of FITC on the activity of FITC labeled protease - Effect of molecular weights of protease on the diffusion - Diffusion and reaction mechanism of proteases in cattle hide matrix En ligne : https://drive.google.com/file/d/1QDPKDq7Hvzq6ren7nS9eHkiT-NiXMA66/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21285 [article]

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Effects of chain transfer agents on properties of AA/BA/AM copolymer retanning agents / Bin Lyu in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 101, N° 1 (01-02/2017)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 101, N° 1 (01-02/2017) . - p. 10-15 Titre : Effects of chain transfer agents on properties of AA/BA/AM copolymer retanning agents Type de document : texte imprimé Auteurs : Bin Lyu, Auteur ; Jia Lu, Auteur ; Jianzhong Ma, Auteur ; Dangge Gao, Auteur ; Dong Ma, Auteur Année de publication : 2017 Article en page(s) : p. 10-15 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Copolymère acide acrylique acrylate de butyle acrylamide Cuirs et peaux -- Propriétés mécaniques Diffractométrie de rayons X Fourier, Spectroscopie infrarouge à transformée de Microscopie électronique à balayage Polyaddition Polymères -- Analyse Retannage Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The retanning process is one of the most important processes in leather production and which plays a vital role in the modern leather industry. In this paper, copolymers based on acrylic acid (AA), butyl acrylate (BA) and acrylamide (AM), were prepared by free radical polymerization. Chain transfer agents were added during the synthesis process to control the molecular weight of the copolymer. The copolymers with different amounts of chain transfer agent were tested for their molecular weight and other properties. The copolymers were analysed using XRD, GPC and FT-IR. Leathers were retanned with different copolymers and the mechanical properties, and SEM of retanned leather were also examined. The results showed that the increased molecular weight of the copolymers decreased the crystallinity, the functional groups of copolymers did net change significantly when the dosage of chain transfer agents increased. When the amount of chain transfer agents was increased, the copolymer had a smaller molecular weight and the retanned leather showed better elongation at break. When the copolymer molecular weight was larger, the tensile strength and tear strength of retanned leather increased. This is important to help select the appropriate molecular weight acrylic retanning agent for different styles of leather products. Note de contenu : - EXPERIMENTAL PROCEDURES : Materials - Synthesis of the poly AA/BA/AM copolymer - Preparation of leather - Characterization - FT-IR analysis - Mechanical properties - RESULTS AND DISCUSSION : Characteristics of the prepared copolymer solution - Gel permeation chromatography (GPC) - FT-IR analysis of the prepared copolymers solution - XRD analysis of the prepared copolymers - Scanning electron microscope (SEM) - Mechanical properties En ligne : https://drive.google.com/file/d/1w2kH_N0PovJ81YRA4Y7GYM4W1wDFxHJQ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=27983 [article]

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Influence of alcohols on stability and mechanical properties of polyacrylate coating material / Dangge Gao in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 12, N° 6 (11/2015)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 12, N° 6 (11/2015) . - p. 997-1004 Titre : Influence of alcohols on stability and mechanical properties of polyacrylate coating material Type de document : texte imprimé Auteurs : Dangge Gao, Auteur ; Wenbo Zhang, Auteur ; Jianzhong Ma, Auteur ; Congmin Li, Auteur ; Jing Zhang, Auteur Année de publication : 2015 Article en page(s) : p. 997-1004 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Alcools Couches minces -- Propriétés mécaniques Couches minces -- Stabilité Latex Polyacrylates Polymères -- Propriétés mécaniques Index. décimale : 667.9 Revêtements et enduits Résumé : Alcohols such as ethanol, isopropanol, n-propanol, and ethylene glycol were introduced into waterborne polyacrylate latex to study their influence on their stability and mechanical properties of polyacrylate. Ethanol, n-propanol, isopropanol, and ethylene glycol were showed to keep the polyacrylate latex steady when the pH values were higher than 3.00, 6.00, 3.00, and 2.50, respectively, as determined by centrifugation. The latex stability vs time was studied by Turbiscan LAB and the results are in good agreement with the change of latex particle size observed by dynamic light scattering. The results indicate that the particle size was affected by the alcohol molecular structure. Alcohol amounts and type had effects on breaking strength and elongation at break of polyacrylate film to varying degrees. The latex film-forming process was measured and morphology of the latex film was observed by scanning electron microscope. Different performances of mechanical properties were caused by the morphology of latex film resulting from the forming process. Note de contenu : - EXPERIMENTAL : Materials - Synthesis of polyacrylate latex - Stability of PA incorporated with alcohols - Film preparation - Characterization - RESULTS AND DISCUSSION : Stability of PA latex - Effect of alcohol on physical properties of latex films DOI : 10.1007/s11998-015-9685-0 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-015-9685-0.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=24932 [article]

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Preparation and characterisation of sulfonated calix[4]arene and its application in chrome-free tanning / Yongxiang Zhou in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 102, N° 4 (07-08/2018)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 102, N° 4 (07-08/2018) . - p. 200-203 Titre : Preparation and characterisation of sulfonated calix[4]arene and its application in chrome-free tanning Type de document : texte imprimé Auteurs : Yongxiang Zhou, Auteur ; Jianzhong Ma, Auteur ; Dangge Gao ; Wenbo Li ; Yao Zhang Année de publication : 2018 Article en page(s) : p. 200-203 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Agents de tannage Calixarènes Un calixarène est un macrocycle issu de la réaction d'un phénol et d'un aldéhyde. Les calixarènes ont des cavités hydrophobiques qui peuvent inclure des petites molécules ou des ions. Les plus couramment rencontrés sont les calixarènes à 4, 5, 6 et 8 unités phénols. La cavité ainsi formée permet de complexer des ions ou des petites molécules. On peut accéder à des calixarènes hydrosolubles en ajoutant des motifs ioniques par exemple. Le terme calixarène est l'assemblage des mots calice (pour la forme de vase que certains calixarènes adoptent à l'état solide) et d'hydrocarbure aromatique arène (pour les cycles aromatiques formant les parois de ce vase). Il a été inventé en 1975 par David Gutsche. Caractérisation Chrome trivalent -- Recyclage Composés inorganiques -- Synthèse Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux de chèvres Sulfonation Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Chrome tanning is the main tanning leather method. However, the absorption of chromium is incomplete and residues are present in waste liquors thus polluting the environment. Moreover, Cr3+ will oxidise into carcinogenic Cr6+ under certain conditions. Here we a present a novel chrome-free tannage. The calix[4]arene was synthesized using tert-butyl phenol and formaldehyde as raw materials. The calix[4]arene was then sulfonated with concentrated sulfuric acid. The structure was characterised by FTIR and 1HNMR. The sulfonated calix[4]arene was applied in goatskin tanning. The results showed that the sulfonated calix[4]arene had a tanning effect. The physical and mechanical, properties of the tanned leather were better than those of conventional chrome-tanned leather. Note de contenu : - Materials - Synthesis of sulfonated calix[4]arene - Characterisation - Application and detection method En ligne : https://drive.google.com/file/d/1sECRJPhRfQzPKkOT0cIgBaepWYDuuezL/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30903 [article]

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