1-butyl-3-methylimidazolium acetate as an alternative solvent for type I collagen / Jie Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIX, N° 6 (06/2014)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIX, N° 6 (06/2014) . - p. 189-196 Titre : 1-butyl-3-methylimidazolium acetate as an alternative solvent for type I collagen Type de document : texte imprimé Auteurs : Jie Liu, Auteur ; Zhou Xu, Auteur ; Chen Yi, Auteur ; Haojun Fan, Auteur ; Bi Shi, Auteur Année de publication : 2014 Article en page(s) : p. 189-196 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Chimie analytique Collagène -- Solubilité Solvants -- Suppression ou remplacement Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Low solubility and undesirable denaturation in conventional solvents continue to represent a significant challenge for efficient extraction, accurate characterization and versatile processing of collagen. In the present study, a room temperature ionic liquid (IL), 1-butyl-3-methylimidazolium acetate ([BMIM]Ac), was synthesized, and then evaluated as an alternative solvent for type I collagen. Real-time polarizing optical microscope observation indicated complete disintegration of hierarchical structure of collagen aggregates as solubilized in [BMIM]Ac at 25°C. The solubility reached up to approximately 8.0 wt.% at 25°C, more than ten times higher than that in conventional dilute acetic acid. In comparison with dilute acetic acid and recently reported chloridion ILs, high solubility of collagen in [BMIM]Ac at room temperature was ascribed to loose binding between [BMIM]+ and acetate, as well as stronger proton-accepting ability of [BMIM]Ac, which enabled rupture of those intermolecular hydrogen bonds and ionic bonds that stabilized collagen aggregates. However, such bond-rupturing effect was found selective at room temperature. As demonstrated by Fourier transform infrared, circular dichroism, atomic force microscope, and ultrasensitive differential scanning calorimetry analysis, [BMIM]Ac did not destroy the special triple-helical structure of tropocollagen molecules that had been identified as being of importance for the functional and bioactive properties of collagen. According to these results, the discovery of [BMIM]Ac as an ideal solvent for collagen may open up new possibilities for the chemistry and engineering of collagen, which has long been established as a readily accessible and renewable resource with many unique properties. Note de contenu : - EXPERIMENTAL : Materials - Synthesis of [BMIM]Ac - Dissolution of collagen in [BMIM]Ac - Polarizing optical microscope (POM) observation - FTIR analysis - CD measurement - AFM observation - DSC measurement - RESULTS AND DISCUSSION : Dissolution mechanism of collagen in [BMIM]Ac - Triple-helical structure of collagen regenerated from [BMIM]Ac En ligne : https://drive.google.com/file/d/1sm3cYDSvhjqbYBv8WJIDxo4nbF5k-kaO/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21517 [article]

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Poly(N-acryloyl ciprofloxacin-co-acrylic acid)-incorporated waterborne polyurethane leather coating with long-lasting antimicrobial property / Jinming Chang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXII, N° 1 (01/2017)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXII, N° 1 (01/2017) . - p. 15-22 Titre : Poly(N-acryloyl ciprofloxacin-co-acrylic acid)-incorporated waterborne polyurethane leather coating with long-lasting antimicrobial property Type de document : texte imprimé Auteurs : Jinming Chang, Auteur ; Gaofu Yang, Auteur ; Qi Zeng, Auteur ; Zhonghui Wang, Auteur ; Zhou Xu, Auteur ; Yi Chen, Auteur Année de publication : 2017 Article en page(s) : p. 15-22 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antimicrobiens Copolymères -- Synthèse Croûte (cuir) On entend par "cuir en croûte" des cuirs ayant subi les opérations jusqu'au tannage, à l'exclusion de toute opération de corroyage ou de finissage, mais qui, par opposition aux wet-blue ont été séchés. Cuirs et peaux -- Finition Polymères -- Synthèse Polymères en émulsion Polyuréthanes Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : o overcome the leaching problem associated with low-molecular-weight antimicrobial agents, a water soluble antimicrobial polymer, poly(N-acryloyl ciprofloxacin-co-acrylic acid), was designed and synthesized via acryloylation of the secondary amine in 7-piperazinyl substituent of ciprofloxacin and subsequent copolymerization with acrylic acid. The structure of the copolymer was characterized by 1H nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectra, X-ray photoelectron spectroscopy (XPS), and gel permeation chromatography (GPC). The copolymer was compatible with waterborne polyurethane for leather finishing, and remained antimicrobial even though the parent structure of ciprofloxacin molecule was altered. When incorporated into waterborne polyurethane leather coating as an antimicrobial agent, poly(N-acryloyl ciprofloxacin-co-acrylic acid) proved seldom leached out from the coating even after being rinsed for ten times. Based on these results, the water soluble antimicrobial copolymer designed in this study may prevent depletion of antimicrobial function of waterborne polyurethane leather coating, extending the lifetime of the leather products and enhancing their hygiene properties. Note de contenu : - Materials - Preparation of N-acryloyl ciprofloxacin (NACPF) - Synthesis of Poly(N-acryloyl ciprofloxacin-co-acrylic acid) - Characterization of Poly(NACPF)-co-AA) - Crust leather finishing by Poly(NACPF)-co-AA) incorporated WPU - Scanning Electron Microscope (SEM) observatin - Bactericidal test - Statistics En ligne : https://drive.google.com/file/d/123bCchShzKFoVumI-TtZ60-U7yV0pE91/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=27565 [article]

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A simple approach with scale-up potential towards intrinsically flame-retardant bio-based co-plasticizer for PVC artificial materials / Yong Xu in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 2 (Année 2020)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 2 (Année 2020) . - 9 p. Titre : A simple approach with scale-up potential towards intrinsically flame-retardant bio-based co-plasticizer for PVC artificial materials Type de document : texte imprimé Auteurs : Yong Xu, Auteur ; Songhang Wang, Auteur ; Jinming Chang, Auteur ; Zhou Xu, Auteur ; Qi Zeng, Auteur ; Zhonghui Wang, Auteur ; Jun Yan, Auteur ; Yi Chen, Auteur Année de publication : 2020 Article en page(s) : 9 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Biomatériaux Chlore Chlorure de polyvinyle Cuir synthétique Esters méthyliques d'acides gras Ignifugeants Composé chimique utilisé pour réduire l'inflammabilité. Il peut être incorporé au produit durant sa fabrication ou appliqué ultérieurement à sa surface. Plastifiants Index. décimale : 668.9 Polymères Résumé : As an imitation of genuine leather, polyvinyl chloride (PVC) artificial materials are versatile, but suffers from being flammable due to the presence of large amounts of combustible plasticizers. Under such circumstance, intrinsically flame-retardant plasticizers displaying dual functions have been a subject of intensive research interest. However, previous strategies attempting to covalently attach flame-retardant moiety to plasticizers invariably required either expensive starting materials or laborious and tedious procedures, ultimately limiting their scale-up application in industry. In addition, driven by escalating demand of halogen-free flame retardants worldwide from an environmental health perspective, previously reported intrinsically flame-retardant plasticizers were mainly halogen-free, less attractive in PVC artificial material industry simply because PVC itself is a halogen-containing polymer. Here, we report an approach to introduce chlorine moieties into unsaturated fatty acid methyl ester by a simple addition reaction occurring on carbon-carbon double bonds, yielding a chlorine-containing, intrinsically flame-retardant bio-plasticizer. When combined with di-(2-ethylhexyl) phthalate (DOP) in PVC formulations, the chlorinated fatty acid methyl ester is qualified as a co-plasticizer while conferring flame retardancy upon the PVC coatings. This approach involves only a one-step procedure that employs renewable fatty acid methyl esters and cheap chlorine gas as raw materials, thus being of great potential to enable intrinsically flame-retardant bio-plasticizers on a large scale to manufacture functional PVC artificial materials for application in fire-prone scenarios. Note de contenu : - Materials - Synthesis of chlorinated fatty acid methyl ester (CFAME) - Preparation of plasticized PVC coating - Characterization - Table 1 : Composition of PVC/CFAMEx - Table 2 : Composition of CFAME identified by comparing the experimental mass spectra of the components in Fig. 3 against NIST08 mass spectral library - Table 3 : Glass transition temperatures of PVC/CFAMEx coatings as determined by DMA analysis - Table 4 : TGA data of PVC/CFAMEx coatings DOI : https://doi.org/10.1186/s42825-020-00022-3 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-020-00022-3.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37333 [article]

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Thermally responsive collagen switching from bactericidal for ambient storage condition to biologically inert in vivo / Jinming Chang in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIII, N° 4 (04/2018)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIII, N° 4 (04/2018) . - p. 114-121 Titre : Thermally responsive collagen switching from bactericidal for ambient storage condition to biologically inert in vivo Type de document : texte imprimé Auteurs : Jinming Chang, Auteur ; Zhou Xu, Auteur ; Gaofu Yang, Auteur ; Zhonghui Wang, Auteur ; Yi Chen, Auteur ; Haojun Fan, Auteur Année de publication : 2018 Article en page(s) : p. 114-121 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antimicrobiens Collagène -- Conservation Composés organiques -- Synthèse Poly(n-isopropylacrylamide) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Incorporating preservatives is now the most commonly employed strategy to prevent microbial deterioration of collagen. However, many preservatives are non-selective; they cannot differentiate the orthologs in mammalian cells from their biological targets in pathogens, and thus their incorporation compromises the inherent biocompatibility of naturally occurring collagen. Here, we report a strategy to covalently anchor antibacterial agents to collagen via a thermally responsive poly(N-isopropylacrylamide) spacer. As the spacer suddenly collapses from an extended coil upon heating through ~30°C, bioactivity of the anchored antibacterial agents can be switched off, because their lateral mobility and, hence, target-site accessibility are restricted. Accordingly, the modified collagen can be preserved without microbial deterioration for ambient storage condition, while imposing no cytotoxic impact upon surrounding tissues in vivo. This thermally responsive collagen holds great potential in biomedical fields, where the collagen products are intended to have intimate contact with human tissues or be administered parenterally. Note de contenu : - Materials - Synthesis of NHS ester-activated RAFT agent - Synthesis of N-acryloyl ciprofloxacin - Synthesis of PNIPAM-ciprofloxacin conjugate - Covalent anchoring of PNIPAM-ciprofloxacin conjugate onto collage - Characterization En ligne : https://drive.google.com/file/d/1tQt8XtEUmJ7NxBB2IyUcepNHuJXcEXyK/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30340 [article]

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Waterborne dimethylolpropionic acid-diisocyanate adducts with alkali-deblockable isocyanate groups as pretanning agent for chrome tanning / Jie Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CX, N° 2 (02/2015)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CX, N° 2 (02/2015) . - p. 43-53 Titre : Waterborne dimethylolpropionic acid-diisocyanate adducts with alkali-deblockable isocyanate groups as pretanning agent for chrome tanning Type de document : texte imprimé Auteurs : Jie Liu, Auteur ; Zhou Xu, Auteur ; Chen Yi, Auteur ; Haojun Fan, Auteur Année de publication : 2015 Article en page(s) : p. 43-53 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Agents de tannage Bisulfite de sodium Caractérisation Collagène Cuirs et peaux -- Propriétés organoleptiques Cuirs et peaux de chèvres Diisocyanates Eaux usées -- Analyse Isocyanates Morphologie (matériaux) Propionique diméthylol, Acide Réticulation (polymérisation) Stabilité au stockage Structure chimique Tannage au chrome Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Diisocyanates qualify as tanning agent by virtue of their strong tendency to crosslink collagen molecules by reacting with amino groups. However, due to their sensitivity to water, these compounds cannot be used directly in aqueous environment, which is the basis for leather processing. To address this problem, waterborne dimethylolpropionic acid-diisocyanate adducts (WDDAs) with temporarily-blocked isocyanate terminals were prepared in the present paper by using NaHSO3 as blocking agent, and further evaluated as a pretanning agent for chrome tanning. Fourier transform infrared (FTIR) spectra revealed that the isocyanate terminals in WDDAs were successfully blocked by NaHSO3. The blocked isocyanates were stable under ambient temperature, but prone to deblocking under alkaline condition. The regenerated isocyanates were found still capable of crosslinking collagen molecules to impart hydrothermal stability. In leather tanning, a high shrinkage temperature (Ts>110°C) was achieved by successively treating goat skin with 5 wt% WDDAs and 4 wt% chrome powder. Stereomicroscope and SEM observation further indicated that the WDDA-chrome tanned leather exhibited tight grain surface and well opened up fiber structure in comparison with semi-chrome tanned leather. Due to the presence of carboxyl group in dimethylolpropionic acid, it was also found that WDDAs enhanced the absorption of chromium in the resultant leathers (% chrome uptake> 90%), resulting in significantly less Cr residual in the tanning wastewater. In addition, it is important to note that the usage of salt in pickling process was avoided owing to previous crosslinking of amino groups, which is very helpful for overcoming the problem of total dissolved solid (TDS) related to neutral salts. The tanning effect of WDDAs and their auxiliary function for chrome tanning allow them to be applicable as a pretanning agent, which efficiently alleviates the environmental impact of traditional chrome tanning for sustainability. Note de contenu : - EXPERIMENTAL PROCEDURES : Materials - Synthesis of WDDA - Characterization of WDDA - Preparation of gelatin modified by WDDA - Characterization of gelatin modified by WDDA - Tanning trial - Assessment of properties of tanned leathers - Stereomicroscope and scanning electron microscope (SEM) observation - Determination of total chromium in tanning wastewater - RESULTS AND DISCUSSION : Chemical structure of WDDAs - Storage stability of WDDAs - Conversion ratio - Reaction between WDDA and collagen - Tanning and tanning wastewater analysis - Organoleptic properties of the tanned leather - Morphologies of grain surface and fibers of the tanned leather En ligne : https://drive.google.com/file/d/1LnUCMds_IewQVvlX8zlBD7CViyxjvVgo/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=23199 [article]

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