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Characterization and thermal properties of polygenipin-crosslinked hide powders / Jie Liu 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) Titre : Characterization and thermal properties of polygenipin-crosslinked hide powders Type de document : texte imprimé Auteurs : Jie Liu, Auteur ; Eleanor M. Brown, Auteur ; Cheng-Kung Liu, Auteur ; Keyong Tang, Auteur Année de publication : 2018 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse thermique Caractérisation Couleur Génipine Poudre de peaux Réticulation (polymérisation) Stabilité thermique Thermogravimétrie Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Genipin is a naturally occurring iridoid compound, it is widely used as an ideal biological protein crosslinking agent due to its low toxicity compared to glutaraldehyde and formaldehyde. Under alkaline condition, genipin could undergo ring-opening polymerization via nucleophilic attack of hydroxyl ions followed by an aldol condensation. Because of the fact that polygenipin could create long-range intermolecular crosslinking between protein chains, preliminary investigations have been carried out to study effect of polygenipin crosslinking on color and thermal stability of hide powder by using colorimetry, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results show that the peak denaturation temperature (Tp) for hide powders obtained from DSC increased to a maximum and then decreased with increasing of the molecular weight of polygenipin. Degree of crosslinking was evaluated, and the results suggest that thermal stability of hide powder is influenced not only by degree of crosslinking, but also by the type of crosslinking. Thermogravimetric analysis also confirms that long-range intermolecular crosslink bridges formed between collagen molecules results in more thermally stable hide powders. This study suggests that polygenipin can be potentially useful in producing eco-friendly leather. Note de contenu : - EXPERIMENTAL : Materials - Preparation of polygenipin - Preparation of the polygenipin crosslinked hide powders - Colors parameters - Degree of crosslinking (DC) - Differential scanning calorimetry (DSC) - Thermogravimetric analysis (TGA) - RESULTS AND DISCUSSION : Characterization of polygenipin - Color parameters of polygenipin crosslinked hide powders - Degree of crosslinking - Differential scanning calorimetry - Thermogravimetric analysis En ligne : https://drive.google.com/file/d/1Llp-sHkQH85153d8dB0r7CFGqTdROUTK/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30338 [article]

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Studies of the application of biocolorant for leather dyeing using Monascus Purpureus / A. Tamil Selvi 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. 105-113 Titre : Studies of the application of biocolorant for leather dyeing using Monascus Purpureus Type de document : texte imprimé Auteurs : A. Tamil Selvi, Auteur ; Gladstone Christopher Jayakumar, Auteur ; N. Usha Rani, Auteur ; Arjunan Yasothai, Auteur Année de publication : 2018 Article en page(s) : p. 105-113 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Chimie -- Essais et réactifs Colorants végétaux Cuirs et peaux -- Teinture Essais dynamiques Extraction (chimie) Fermentation Frottements (mécanique) pH Photostabilité Résistance à l'abrasion Rouge (couleur) Température vision des couleurs Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : World-wide requirement for colorants from natural origins have been rapidly increasing in the leather sector due to environmental effluent concerns. Biocolorant obtained from Monascus purpureus, which yields red colored extract, has been studied for the dyeing process of leather. The effect of varying conditions like pH, concentration, time and temperature on the levelness of the dyeing, shade brightness, color intensity and exhaustion of the dye have been studied herein, and the conditions optimized. The change in color shade obtained has been quantified by reflectance measurements and compared with the visual assessment data. The bulk properties viz., softness and grain smoothness have been found to be marginally improved, versus control, in biocolorant treated leathers. There is no significant change in strength properties by the use of these natural colorants in the post tanning process. Note de contenu : - EXPERIMENTAL : Reagents and chemical - Microorganism - Substrate and solid-state fermentation - Extraction of biocolorant - experimental trials - Effect of concentration (Trial 1) - Effect of pH (Trial 2) - Effect of temperature (Trial 3) - Effect of time (Trial 4) - Control process - Comparison of experimental and control trials - Analysis of dye exhaustion in the process liquor - Determination of color difference - Visual color assessment - Determination of fastness to light - Determination of fastness to wet and dry rub - Physical testing analysis - Assessment of bulk properties - RESULTS AND DISCUSSION : Biocolorant production - Natural colorant applied for dye exhaustion : influence of process parameters - Effect of concentration - Effect of pH - Effect of temperature - Effect of time - Effect of surface color at varied condition of biocolorant treatment - Optimized condition of biocolorant treatment Visual assessment of leathers - Light and rub fastness characteristics of leathers - Evaluation of strength characteristics - Assessment of bulk properties En ligne : https://drive.google.com/file/d/1YA5SIZB5vrTUmFlGbGwcF0-7MSrBXeTF/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30339 [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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Hydrolysis of chromium tanned leather waste : turning waste into valuable materials - A review / Bianca S. Scopel 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. 122-129 Titre : Hydrolysis of chromium tanned leather waste : turning waste into valuable materials - A review Type de document : texte imprimé Auteurs : Bianca S. Scopel, Auteur ; Camila Baldasso, Auteur ; Aline Dettmer, Auteur ; R. M. C. santana, Auteur Année de publication : 2018 Article en page(s) : p. 122-129 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Collagène Cuir -- Déchets Extraction (chimie) Hydrolyse Tannage au chrome Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Among the reuse and/or disposal possibilities for chromium tanned leather waste (CTLW), one in particular stands out: hydrolysis. This process not only allows chromium recovery, but also the extraction of its protein, as collagen hydrolysate or as gelatin. CTLW hydrolysis has been performed for decades. However, industrial application of this important alternative has not been widespread. Thus, this review presents how CTLW alkaline hydrolysis has been evolving over the years; how the process can be adjusted to increase protein extraction yield and to produce better quality products. Finally, it reviews in which areas its products have already been tested. Here, researchers may find practical process information that might allow them to focus on the most important current issue for CTLW hydrolysis: how to upgrade this process to an industrial scale. Note de contenu : - CTLW characterization - CTLW alkaline hydrolysis - Extraction yield and protein quality - Alkalinizing agent and pH - Time and temperature - Application of the fractions obtained from CTLW hydrolysis En ligne : https://drive.google.com/file/d/1OebPs4vZX9TPML4rpOwEWtA0K8ghDNNd/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30341 [article]

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