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Mechanical microscopic analysis in the process of stretching cowskin collagen / Zhong Anhua in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 107, N° 1 (01-02/2023)
[article]
Titre : Mechanical microscopic analysis in the process of stretching cowskin collagen Type de document : texte imprimé Auteurs : Zhong Anhua, Auteur ; Huang Zhuo, Auteur ; Fang Songchun, Auteur ; Zhou Meng, Auteur Année de publication : 2023 Article en page(s) : p. 16-18 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Collagène -- Analyse
Cuirs et peaux -- Propriétés mécaniques
Cuirs et peaux de bovins
Etirement (mécanique)
Microscopie
Traction (mécanique)Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The tensile properties of cowskin leather are expressed in terms of its important mechanical properties. Variation in the collagen of cowhide is the microscopic cause of the tensile properties of cowhide. The aim of this study was to perform molecular dynamics simulations for the collagen stretching process of clothing cowhide at the rate of 0.01nm/ps, on lengths of 10nm. The changes in the RMSD (root square mean deviation of atomic position), SASA (solvent accessible surface), potential energy, and hydrogen bonding of collagen throughout the stretching process were obtained. The RMSD of the collagen fluctuated during the stretching process and tended to equilibrate. SASA increased with increasing voltage and reached a critical condition at 900 ps. In the molecular unwinding and uncoiling stage, the potential energy remained constant and it increased rapidly in the stage of stretching backbone. The numbers of hydrogen bonds within the collagen gradually decreased but increased between collagen and the aqueous solvent, with both hydrogen bonds reaching a turning point at 900ps. Note de contenu : - Research theory
- Experimental procedures
- Results and discussion : RMSD analysis - SASA analysis - Potential energy analysis - Hydrogen bonds analysisEn ligne : https://drive.google.com/file/d/1_x0hOgHg-Dpk_o9VVc7w3D9eLZfokaEg/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38868
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 107, N° 1 (01-02/2023) . - p. 16-18[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 23893 - Périodique Bibliothèque principale Documentaires Disponible Melamine ethoxylates as novel formaldehyde free replacements of resin re-tanning agents / Jochen Ammenn in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVII, N° 7 (07/2022)
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Titre : Melamine ethoxylates as novel formaldehyde free replacements of resin re-tanning agents Type de document : texte imprimé Auteurs : Jochen Ammenn, Auteur Année de publication : 2022 Article en page(s) : p. 296-301 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Agents de tannage
Cuirs et peaux de bovins
Ethoxylates de mélamine
Formaldéhyde -- Suppression ou remplacement
Produits de condensation (chimie)
Retannage
Tannage synthétique
Wet-blue (tannage)Peau tannée au chrome (le chrome donne une couleur bleue)Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Melamine urea formaldehyde condensates or resin re-tanning agents are commonly used in the leather industry. They give rise to homogeneous filling, are easily and widely applicable, but generally contribute to free formaldehyde, measurable in emission or extraction methods. Many projects to resolve this issue have been carried out. The weakness of the resin re-tanning is the reversibility of the bond formation between formaldehyde and two amino groups. The formaldehyde forms a methylene group after condensation with two amino groups and releases water. This methylene group can be hydrolyzed under acidic conditions to release formaldehyde again, reversing the synthesis.
Melamine ethoxylates were found to be a formaldehyde free, stable, and easily applicable alternative. Besides the fact that they are made without formaldehyde, it proved to be possible to incorporate renewable components into their synthesis, giving rise to an even more sustainable product. Another sustainable aspect of this chemistry is the delivery of the potential product as a concentrated liquid versus most resin re-tanning agents being placed into the market as spray dried powders, consuming significant amounts of energy in the process.
Melamine ethoxylates show advantages in application on leather in comparison with classical resin re-tanning agents. An insight into the scope of application will be given, showing that melamine ethoxylates can be considered a formaldehyde free replacement for resin re-tanning agents.Note de contenu : - Melamine urea formaldehyde condensates
- Melamine ethoxylates
- Table 1 : Screening results of the re-tanning of bovine wet blue of different melamine ethoxylates against a standard melamine urea formaldehyde condensate and polyethylene glycol : + = better ; 0 = similar ; — = worse
- Table 2 : Re-tanning of bovine wet blue with the optimized melamine ethoxylate against a standard melamine urea formaldehyde condensate : + = better; 0 = similar ; - = worse
- Table 3 : Results of re-tanning of bovine wet blue or wet white with melamine ethoxylates in a mixed recipe compared to a melamine urea formaldehyde condensate in the mixed recipe : + = better; 0 = similar; - = worseEn ligne : https://drive.google.com/file/d/1cuWtS0wR-6zJregVnQ4eK0FqHZOfhLNC/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37822
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Code-barres Cote Support Localisation Section Disponibilité 23515 - Périodique Bibliothèque principale Documentaires Disponible A method and principle of soft and transparent leather manufacturing / Xiu He in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVIII, N° 11 (11/2023)
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Titre : A method and principle of soft and transparent leather manufacturing Type de document : texte imprimé Auteurs : Xiu He, Auteur ; Jinwei Zhang, Auteur Année de publication : 2023 Article en page(s) : p. 455-461 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuirs et peaux -- Propriétés mécaniques
Cuirs et peaux de bovins
Cuirs et peaux de porcs
Douceur (toucher)
GlycérineLe glycérol, ou glycérine, est un composé chimique de formule HOH2C–CHOH–CH2OH. C'est un liquide incolore, visqueux et inodore au goût sucré, utilisé dans de nombreuses compositions pharmaceutiques. Sa molécule possède trois hydroxyles correspondant à trois fonctions alcool responsables de sa solubilité dans l'eau et de sa nature hygroscopique. Un résidu glycérol constitue l'articulation centrale de tous les lipides de la classe des triglycérides et des phosphoglycérides.
PROPRIETES PHYSIQUES : Le glycérol se présente sous la forme d'un liquide transparent, visqueux, incolore, inodore, faiblement toxique si ingéré (mais laxatif à haute dose), au goût sucré.
Le glycérol peut se dissoudre dans les solvants polaires grâce à ses trois groupes hydroxyles. Il est miscible dans l'eau et l'éthanol ; et insoluble dans le benzène, le chloroforme et le tétrachlorométhane.
Son affinité avec l'eau le rend également hygroscopique, et du glycérol mal conservé (hors dessicateur ou mal fermé) se dilue en absorbant l'humidité de l'air.
- PROPRIETES CHIMIQUES : Dans les organismes vivants, le glycérol est un composant important des glycérides (graisses et huiles) et des phospholipides. Quand le corps utilise les graisses stockées comme source d'énergie, du glycérol et des acides gras sont libérés dans le sang.
- DESHYDRATATION : La déshydratation du glycérol est faite à chaud, en présence d'hydrogénosulfite de potassium (KHSO3) et produit de l'acroléine
- ESTERIFICATION : L'estérification du glycérol conduit à des (mono, di ou tri) glycérides.
- AUTRES PROPRIETES : Le glycérol a un goût sucré de puissance moitié moindre que le saccharose, son pouvoir sucrant est de 0,56-0,64 à poids égal13.
Le glycérol a des propriétés laxatives et diurétiques faibles.
Comme d'autres composés chimiques, tels que le benzène, son indice de réfraction (1,47) est proche de celui du verre commun (~1,50), permettant de rendre "invisibles" des objets en verre qui y seraient plongés.
Procédés de fabrication
Souplesse (mécanique)
Transparence (optique)Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : For preparing a new kind of leather with transmittance and softness at the same time, glycerol was used to treat delimed and bleached split pelt. The softness, transmittance and mechanical properties were tested to evaluate the performance of soft and transparent leather (STL). FT-IR, SEM, XRD, DSC and TG were used to character the structure of STL and reveal the basic principle of STL manufacturing. The results showed that 25% glycerol based on limed pelt weight could make leather soft and transparent simultaneously. Pig pelt was more suitable for thin and transparent leather while cattle split was better for uniform and clear leather. Glycerol combined with collagen through multipoint hydrogen bonds, and the combination had slight positive effect on improving STL thermal stability. Fiber bundles of STL trended to disperse and collagen hierarchical structure including triple helix remained during transparent treatment. The soft and transparent leather could be a new choice for leather goods designers and might be a selectable substrate for high-performance electronic skin. Note de contenu : - EXPERIMENTAL : Materials - Sample preparation - Testing methods
- RESULTS AND DISCUSSION : Performance of soft and transparent leather - Structure of soft and transparent leather - Mechanical of soft and transparent leather manufacturing
- Table 1 : STL manufacturing process
- Table 2 : Mechanical properties of soft and transparent leatherDOI : https://doi.org/10.34314/jalca.v118i11.8239 En ligne : https://drive.google.com/file/d/1lEKZ-YatckFOZlBRajB51bMKEQ6TTGb7/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40044
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Code-barres Cote Support Localisation Section Disponibilité 24291 - Périodique Bibliothèque principale Documentaires Disponible Micro analysis of moisture permeability and its changing trend in thin cowhide / Abigail Clare in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 2 (03-04/2022)
[article]
Titre : Micro analysis of moisture permeability and its changing trend in thin cowhide Type de document : texte imprimé Auteurs : Abigail Clare, Auteur ; Fang Songchun, Auteur ; Wang Ji, Auteur ; Huang Zhuo, Auteur Année de publication : 2022 Article en page(s) : p. 61-64 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Analyse
Cuirs et peaux -- Effets de l'humidité
Cuirs et peaux -- Effets de la température
Cuirs et peaux de bovins
PerméabilitéIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Natural leather has excellent moisture permeability. With the fashionable design of leather clothing, research on the processing and properties of thin natural leather has become more and more important. In this paper, after 0.8mm thin cowhide was obtained using a precision leather machine with blade [splitting machine], the arrangement of protein fibres was observed by a 1000X scanning electron microscope. Under the environmental conditions of a pressure of 1 atmosphere, 40°C and humidity of 69%, it is found that the relationship between the moisture permeability (y) of cow leather and thickness (x) is y = -0.11x + 4.23. The reason why the thinner the cow leather, the better the moisture permeability is was analyzed microscopically ; Secondly, the effects of amblent temperature and moisture permeability time on the moisture permeability of thin leather were investigated. It was found that the higher the temperature, the greater the moisture permeability of thin leather. The moisture permeability of thin leather reached the maximum when the temperature was 80°C. The three-dimensional surface fitting was carried out for the changes of moisture permeability of thin leather with time and temperature. The regression equation of moisture permeability(y) of thin leather with moisture permeability time (t) and temperature (T) was as follows: y=-11.9t2+ 2.498tT - 0.07923T2-91.92t + 4.748T - 46.19. Note de contenu : - EXPERIMENTAL PROCEDURES : Experimental instruments - Experimental materials - Moisture permeability calculation
- RESULTS AND DISCUSSION : Effect of cowhide thickness on moisture permeability and micro analysis - Relationship between moisture permeability of thin cowhide with time and temperature - Comprehensive variation of moisture permeability of thin leather with time and temperatureEn ligne : https://drive.google.com/file/d/1nJaaodm5PRG0asx1fhG-9Y060v0rsYAz/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37484
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Code-barres Cote Support Localisation Section Disponibilité 23351 - Périodique Bibliothèque principale Documentaires Disponible Microscopic analysis of the tensile properties of cattle collagen / Zhong Anhua in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 6 (11-12/2022)
[article]
Titre : Microscopic analysis of the tensile properties of cattle collagen Type de document : texte imprimé Auteurs : Zhong Anhua, Auteur ; Huang Zhuo, Auteur ; Fang Songchun, Auteur ; Jinlong Zhao, Auteur Année de publication : 2022 Article en page(s) : p. 252-254 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Propriétés mécaniques
Cuirs et peaux de bovins
Elasticité
Essais dynamiques
Microscopie
Traction (mécanique)Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The tensile property of cattle leather is an important mechanical property. To study the mechanical properties of cattle leather for clothing, the stretching process of 1CGD was simulated by steered molecular dynamics (SMD). The experiment was set up with 5 temperatures and 5 stretching rates. The stress-strain curves of collagen and Young's modulus of the collagen were obtained during the whole process. The results revealed a significant effect of temperature and stretching rate on the stress-strain curve of collagen. When the temperature is constant, the stress-strain curve decreases with the increase of tensile rate, and the stress-strain curve has three forms: viscoelasticity, upward extension and linear change. The higher temperature, the lower Young's modulus. The higher stretching rate, the lower Young's modulus. Note de contenu : - Research theory
- Experimental procedures
- Results and discussion : Conformation change - Analysis of stress-strain - Analysis of Young's modulusEn ligne : https://drive.google.com/file/d/1g91amVFE_mgAfr6EE8QU1WbfIJNc3HGw/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38517
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Code-barres Cote Support Localisation Section Disponibilité 23756 - Périodique Bibliothèque principale Documentaires Disponible Microscopy methods to study fat cells : Part 1 : characterisation of ovine cutaneous lipids using microscopy / V. L. Addy in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 85, N° 1 (01-02/2001)
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PermalinkOrganisation de la lutte contre l'hypodermose bovine / Paris : Agence européenne de productivité de l'Organisation Européenne de Coopération Economique (OECE) (1957)
PermalinkPhysicochemical properties of collagen, gelatin and collagen hydrolysate derived from bovine limed split waste / Zhongkai Zhang in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 90, N° 1 (01-02/2006)
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PermalinkPreservation of cattlehides with electron beam irradiation / David G. Bailey in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXXIV (Année 1989)
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