Characteristics of leather tanned with Nano-SIO2 / Haojun Fan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. C, N° 1 (01/2005)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. C, N° 1 (01/2005) . - p. 22-28 Titre : Characteristics of leather tanned with Nano-SIO2 Type de document : texte imprimé Auteurs : Haojun Fan, Auteur ; Biyu Peng, Auteur ; Qiang He, Auteur ; Bi Shi, Auteur ; Ling Li, Auteur Année de publication : 2005 Article en page(s) : p. 22-28 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : A nano-precusor which can, in-situ, produce nano-SiO2 under particular triggering condition was introduced into leather to improve the hydrothermal stability. In order to elucidate the reaction of nano-SiO2 with proteinand how it influences the properties of the protein, collagen was used as a model in a detailed investigation. The results from FTIR (Infrared) indicated that two new chemical bonds arose during the formation of the organic-inorganic nano-hybrid. One appears to be the reaction between nano-SiO2 formed in-situ by the hydrolysis of tetraethoxy silane and the -C=N-groups of arginine, histidine, and tryptophane in the backbone of collagen. In a second bond, occurring at the same time as the condensation of silanol proceeds, the pendent hydroxyl groups of collagen may partly react with Si-OH and form a strong interaction between the organic and inorganic phases. These two chemical bonds seem to contribute to the leather's high hydrothermal stability. The size distribution of nano-SiO2 as determined by Atomic Force Microscopy is approximately 50-80 nm and there appeared to be no agglomeration. Organic-inorganic nano-hybrid can improve the hydrolysis stability of collagen efficiently in the presence of enzyme, acid, and alkali. When the bated pelt is treated with 0.3 wt % nano-SiO2 (based on bated pelt weight), the shrinkage temperature reached above 95°C. Although the mechanical properties of nano-SiO2 tanned leather are inferior to chromium tanned leather, other properties of nano-SiO2 tanned leather, such as yield, grain, fullness and softness together with washability are all superior to chromium tanned leather. En ligne : https://drive.google.com/file/d/1ohLq2CUJ-Oo_mR-8noT-ldL7pN59s7c6/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4087 [article]

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The water vapour permeability of leather finished by thermally responsive polyurethane / Haojun Fan in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 89, N° 3 (05-06/2005)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 89, N° 3 (05-06/2005) . - p. 121-125 Titre : The water vapour permeability of leather finished by thermally responsive polyurethane Type de document : texte imprimé Auteurs : Haojun Fan, Auteur ; Ling Li, Auteur ; Xinnian Fan, Auteur ; Bi Shi, Auteur Année de publication : 2005 Article en page(s) : p. 121-125 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse thermomécanique dynamique Butanediol Caractérisation Cuirs et peaux -- Finition Diisocyanate d'isophorone Gonflement (physique) Matériaux thermosensibles Mesure Perméabilité Poly-e-caprolactone Polymères en émulsion Polyuréthanes Propionique diméthylol, Acide Revêtements organiques Transition de phase En physique, une transition de phase est une transformation du système étudié provoquée par la variation d'un paramètre extérieur particulier (température, champ magnétique...). Cette transition a lieu lorsque le paramètre atteint une valeur seuil (plancher ou plafond selon le sens de variation). La transformation est un changement des propriétés du système. Vapeur d'eau Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A water-based thermally-responsive polyurethane (TRPU), based on the crystalline soft segment from the reaction of polycaprolactone diol (PCL) with isophorone diisocyanate (IPDI) and the crystalline hard segment from the reaction of IPDI -1,4-butanediol (BDO) together with dimethylolpropionic acid (DMPA), was synthesized and used in water vapour permeable leather finishing. Differential Scanning Calorimetry (DSC), Dynamic Mechanical Thermal Analyzer (DMTA), water swelling and water vapour permeability (WVP) were measured to evaluate how the structure of PU and the temperature influence the WVP of PU films and finished leathers. In contrast to common polyurethane elastomer (PUE) with an amorphous reversible phase, the TRPU with a crystalline reversible phase shows a phase-separated structure and a phased transition temperature (Ttrans) at normal use temperature. The water swelling and water vapour permeability of both TRPU film and finished leather are found to depend on the inner structure of the polymers and the temperature. When the temperature exceeds the Ttrans, a significant increase of WVP from 4100g/m2/day to 10500g/m2/day was observed for finished leather in spite of some decrease of WVP compared with un-finished leather. Leather finished with common PUE appears to have a low WVP and only a slightly increased value over the temperature range. Note de contenu : - EXPERIMENTAL PROCEDURE : Material, preparation of polyurethane and testing - Film casting and leather specimen preparation - Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Thermal Analyzer (DMTA) - Water swelling of PU films - Measurement of water transport properties - RESULTS AND DISCUSSION : Phase transition temperature of polyurethanes - Water swelling of PU films - Water vapour permeability - Table 1 : Characteristics of the TRPU and PUE prepared - Table 2 : Storage modulus of PU samples as a function of temperature - Table 3 : Comparison of water swelling of different PU films En ligne : https://drive.google.com/file/d/1qQXbjgGgLXlKIkAE_ZSG7m0uac1UdoeO/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39272 [article]

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