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Chrome-melamine syntan : a step towards developing fuller leather / P. Balasubramanian in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CX, N° 10 (10/2015)
[article]
Titre : Chrome-melamine syntan : a step towards developing fuller leather Type de document : texte imprimé Auteurs : P. Balasubramanian, Auteur ; Z. Mohammad Jamal Azhar, Auteur ; Rathinam Aravindhan, Auteur ; Kalarical Janardhanan Sreeram, Auteur ; Jonnalagadda Raghava Rao, Auteur ; Balachandran Unni Nair, Auteur Année de publication : 2015 Article en page(s) : p. 332-336 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Caractérisation
Chrome
Cuirs et peaux -- Analyse
Eaux usées -- Analyse
Essais (technologie)
MélamineLa mélamine, de nom chimique 1,3,5-triazine-2,4,6-triamine, est parfois dénommée cyanuramide ou cyanurotriamine. Sa formule brute est C3H6N6.
Les "résines mélamine-formaldéhyde" ou "mélamine-formol" (sigle MF) sont appelées "mélamine" dans le langage courant. Elles font partie de la famille des aminoplastes qui regroupe des résines thermodurcissables aminées, issues d'un comonomère tel l'urée ou la mélamine, parfois le thiocarbamide, le cyanamide hydrogène ou le dicyandiamide ; le second comonomère étant le formaldéhyde.
Morphologie (matériaux)
Réticulants
SyntansIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : The leather industry operates in stages. Many of the finished leather manufacturers source their wet blue leathers from various regions or tanners. In order to have uniformity of metal oxide content, almost all the leathers are rechromed. For this, the industry employs masked chromium(III) salts provided by the leather auxiliary industry in the form of complexes co-linked to phenol/ naphthalene condensates. Also, tanners who use hides/skins from ill fed animals treat their tanned substrate with melamine condensates, so as to get a preferential filling of the belly region. Metal ion complexes co-linked to melamine condensates are rather scarce. For the first time, this paper reports the application studies using a chromium melamine condensate devoid of formaldehyde as cross linker. The said product has been employed in rechroming and evaluated for multiple properties such as providing an equalization of chrome content and filling of belly region. Our studies clearly indicate a marked advantage of employing such a product in the place of commercial chrome syntans alongside melamine condensates, more so for ill fed cowhides. Note de contenu : - MATERIALS AND METHODS : Materials - Preparation of chrome melamine syntan - Characterization of SYN1 - Experiments employing SYN1 - Physical testing and hand evaluation of leathers - Morphological analysis - Analysis of rechrome liquor
- RESULTS AND DISCUSSION : Preparation of SYN1 - Characterization of SYN1 - Physical testing and hand evaluation of leathers - Morphological analysis - Analysis of wastewaterEn ligne : https://drive.google.com/file/d/1mu1h5zouz_i6qIQN9YHkXALMDJP1-fTP/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=24744
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Code-barres Cote Support Localisation Section Disponibilité 17500 - Périodique Bibliothèque principale Documentaires Disponible Chromium-keratin tanning compound - preparation, characterization and application in tanning process / R. Karthikeyan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVII, N° 5 (05/2012)
[article]
Titre : Chromium-keratin tanning compound - preparation, characterization and application in tanning process Type de document : texte imprimé Auteurs : R. Karthikeyan, Auteur ; Chandra Babu Narasimhan Kannan, Auteur ; Praveen Kumar Sehgal, Auteur Année de publication : 2012 Article en page(s) : p. 149-158 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Caractérisation
Chrome
Cuirs et peaux de chèvres
kératineLa kératine est une protéine, synthétisée et utilisée par de nombreux êtres vivants comme élément de structure, et également l'exemple-type de protéine fibreuse.
La kératine est insoluble, et peut être retrouvée sur l'épiderme de certains animaux, notamment les mammifères, ce qui leur garantit une peau imperméable. Parfois, lors d'une friction trop importante, la kératine se développe à la surface de la peau formant une callosité. Les cellules qui produisent la kératine meurent et sont remplacées continuellement. Les morceaux de kératine qui restent emprisonnés dans les cheveux sont couramment appelés des pellicules.
La molécule de kératine est hélicoïdale et fibreuse, elle s'enroule autour d'autres molécules de kératine pour former des filaments intermédiaires. Ces protéines contiennent un haut taux d'acides aminés à base de soufre, principalement la cystéine, qui forment un pont disulfure entre les molécules, conférant sa rigidité à l'ensemble. La chevelure humaine est constituée à 14 % de cystéine.
Il y a deux principales formes de kératines : l'alpha-kératine, ou α-keratin, présente chez les mammifères notamment, dont l'humain, et la bêta-kératine, ou β-keratin, que l'on retrouve chez les reptiles et les oiseaux. Ces deux types de kératines ne présentent clairement pas d'homologie de séquence.
Chez l'être humain, la kératine est fabriquée par les kératinocytes, cellules se trouvant dans la couche profonde de l'épiderme. Les kératinocytes absorbent la mélanine (pigment fabriqué par les mélanocytes), se colorent et ainsi cette pigmentation de l'épiderme permet de protéger les kératinocytes des rayons ultraviolets du Soleil.
TannageTags : 'Tannage chrome/kératine' Caractérisation 'Détermination teneur chrome' Basicité Soufre 'Spectroscopie transformée Fourier' 'Masse molaire' rayons X' 'Mesure couleur' Prétannage 'Peaux chèvres' 'Procédure tannage' 'Stabilité thermique' DSC MALDI-TOF EDX 'Microscopie électronique balayage' 'Dichromate acidifié' Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : A chromium-keratin tanning compound has been prepared by treating chicken feathers with acidified dichromate. The newly developed chromium-keratin compound contain ~ 17% w/w Cr2O3 and protein content of ~10% w/w. The chromium-keratin compound has been characterized using FT-IR, MALDI-TOF, EDX and computer aided color analysis. Tanning studies have been carried out with goat skins, where the chromium-keratin compound has been used as chrome tanning agent in place of basic chromium sulfate (BCS). The denaturation temperature of chromium-keratin tanned leather analyzed by DSC shows a value of 112°C and the percentage exhaustion of chromium in the tanning bath is greater than 80 percent. Structural and physical characteristics of chromium-keratin compound treated leathers were analyzed using standard techniques and the results were compared with the control leathers tanned with commercial BCS. Note de contenu : - EXPERIMENTAL : Materials and methods - Development of chromium-keratin compound - Determination of chromium content and basicity - Determination of protein content - Estimation of total sulfur - Fourier Transform Infrared Spectroscopy (FT-IR) - Determination of molar mass of species in the chromium-keratin compound using MALDI-TOF - Energy dispersive X-ray spectroscopy (EDX) analysis of chromium-keratin compound - Color measurement analysis
- TANNING STUDIES : Pretanning procedure for goat skins - Tanning procedure - Determination of thermal stability by differential scanning calorimetry (DSC) - Analysis of spent tan liquors - Post tanning - SEM analysis - Physical testing and visual examination of web blue
- RESULTS AND DISCUSSION : Effect of chicken feathers (CF) on the reduction of Cr(VI) - Chemical characteristics of chromium-keratin compound - FT-IR characterizationof chromium-keratin compound - Molar masses of species present in chromium-keratin compound by MALDI-TOF - Color measurement data - Characteristics of chromium-keratin compound tanned leathers - Scanning electron microscope analysis - Spent liquor analysis - Physical testing dataEn ligne : https://drive.google.com/file/d/1iqT9eBfS3WOdIeieYmUU3UH1bPcnQVhP/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15001
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Code-barres Cote Support Localisation Section Disponibilité 13916 - Périodique Bibliothèque principale Documentaires Disponible Chromium leachatiblity from leather waste and eco-toxicity under environmental conditions / Peng Liang-Qiong in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 3 (03/2020)
[article]
Titre : Chromium leachatiblity from leather waste and eco-toxicity under environmental conditions Type de document : texte imprimé Auteurs : Peng Liang-Qiong, Auteur ; Long Wen-Jun, Auteur ; Li Yue, Auteur ; Wen-Hua Zhang, Auteur ; Bi Shi, Auteur Année de publication : 2020 Article en page(s) : p. 87-95 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Caractérisation
Chimie analytique
Chrome
Cuir -- Déchets
Ecotoxicologie
Environnement -- Etudes d'impact
Evaluation
LixiviationIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Chromium (III) is currently used in leather manufacture worldwide and the attention has been centered on the alleged environmental impact of chromium in leather waste. The effects of liquid-solid ratio, pH, contact time, rotational speed and temperature on the leachability of chromium from leather waste and the eco-toxicity were evaluated to investigate the ecological impact under environmental conditions. The characterization of leachate included the determination of total Cr and total organics (TOC), analysis of UV-visible absorption spectra, as well as the toxicity test with Photobacterium phosphoreum. The liquid-solid ratio, extractant pH, contact time and temperature significantly affected the leachability of chromium and toxicity of the leachate, whereas rotational speed slightly affected the leaching behavior when beyond 100 RPM. The toxicity of the leachate was related to both the amount of released substance which was mainly affected by contact time and liquid-solid ratio, and the species which was mainly affected by temperature and extractant pH. Finally, three samples from different tannery corresponding to leather waste were leached and characterized by total Cr, TOC and toxicity test under the environmental conditions of liquid-solid ratio 20:1(mL/g), pH 7.0, contact time 8 hours, rotational speed 100 RPM and temperature 25°C. These results contributed to the risk assessment of stacking field and waste management of chrome-containing leather. Note de contenu : - MATERIALS AND METHODS : Materials - Leaching experiments - Chromium analysis - Total organics analysis - UV-visible absorption spectra - Toxicological assays
- RESULTS AND DISCUSSION : Release behavior of chromium and organics from leather waste - Effect of liquid/solid ratio - Effect of pH - Effect of contact time - Effect of rotational speed - Effect of temperature
- TECHNOLOGICAL ASSAYS : Effect of liquid/solid ration - Effect of pH - Effect of contact time - Effect of rotational speed - Effect of temperature - Assessment of chrome-tanned leather wastesDOI : https://doi.org/10.34314/jalca.v115i03.1626 En ligne : https://drive.google.com/file/d/16PobO8GJAa-9BnwXcmCU7RA3a3jZ-kix/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33886
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Code-barres Cote Support Localisation Section Disponibilité 21626 - Périodique Bibliothèque principale Documentaires Disponible CO2-triggered hydrophobic/hydrophilic switchable waterborne polyurethane-acrylate with simultaneously improved water resistance and mechanical properties / Liangfeng Xu in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 18, N° 4 (07/2021)
[article]
Titre : CO2-triggered hydrophobic/hydrophilic switchable waterborne polyurethane-acrylate with simultaneously improved water resistance and mechanical properties Type de document : texte imprimé Auteurs : Liangfeng Xu, Auteur ; Zhaofei Wang, Auteur ; Gongwen Yang, Auteur ; Guobing Zhang, Auteur ; Haibing Wei, Auteur ; Huagao Fang, Auteur ; Yunsheng Ding, Auteur Année de publication : 2021 Article en page(s) : p. 989–998 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse thermique
Caractérisation
Copolymère uréthane acrylate
Méthacrylate de méthyle
Polymères -- Propriétés mécaniques
Polymères -- Synthèse
Polymères en émulsion
Polyuréthanes
Résistance à l'humidité:Résistance à l'eau
Revêtements -- Propriétés thermiques
Revêtements organiques
ThermogravimétrieIndex. décimale : 667.9 Revêtements et enduits Résumé : Traditional waterborne polyurethane (WPU) has poor water resistance because of the incorporation of permanent hydrophilic groups, such as carboxyl group or ammonium salt, into polymer chains. Therefore, developing WPU with excellent water resistance and mechanical properties is highly desirable for industrial applications. In this study, CO2-triggered hydrophobic/hydrophilic switchable waterborne polyurethane–acrylate (WPUA) containing methyl methacrylate (MMA) units were designed and synthesized. The molecular structure, hydrophobic/hydrophilic switchable behavior, water resistance, and mechanical properties were systematically investigated and characterized. The WPUA with 10 wt% MMA exhibited a low water uptake (2.15 wt%) and linear swelling ratio (0.17 L%), as well as a high tensile strength (16.7 MPa) and modulus (85.9 MPa), which were much higher than those of the pristine WPU. This study indicated that the CO2-triggered WPUA dispersed stably as latex particles in water and possessed excellent water resistance and mechanical properties after the film formation. Note de contenu : - EXPERIMENTAL : Materials - Synthesis of WPU and WPUA emulsions - Preparation of WPU and WPUA films - Characterizations
- RESULTS AND DISCUSSION : Structures of WPU-pre, WPU, and WPUA filmsHydrophilic/hydrophobic switchable behaviors
of WPUA emulsions - Water resistance of WPU and WPUA films - Mechanical and thermal properties of WPU
and WPUA films - Thermal properties of WPU and WPUA films
- Table 1 : The compositions of WPU and WPUA emulsions
- Table 2 : The linear swelling ratio, water uptake, water contact angle, and gel content of WPU and WPUA
- Table 3 : Mechanical data of WPU and WPUA films
- Table 4 : TGA and DSC data of WPU and WPUA filmsDOI : https://doi.org/10.1007/s11998-021-00476-y En ligne : https://link.springer.com/content/pdf/10.1007/s11998-021-00476-y.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36207
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Code-barres Cote Support Localisation Section Disponibilité 22969 - Périodique Bibliothèque principale Documentaires Disponible Coal-derived, solid resins as economic raw materials for coatings / Stefan Holberg in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 18, N° 3 (05/2021)
[article]
Titre : Coal-derived, solid resins as economic raw materials for coatings Type de document : texte imprimé Auteurs : Stefan Holberg, Auteur ; Xinyan Wang, Auteur ; William C. Schaffers, Auteur ; David A. Bell, Auteur ; Jeramie J. Adams, Auteur ; Patrick A. Johnson, Auteur Année de publication : 2021 Article en page(s) : p. 921-931 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Acier L'acier est un alliage métallique utilisé dans les domaines de la construction métallique et de la construction mécanique.
L'acier est constitué d'au moins deux éléments, le fer, très majoritaire, et le carbone, dans des proportions comprises entre 0,02 % et 2 % en masse1.
C'est essentiellement la teneur en carbone qui confère à l'alliage les propriétés du métal qu'on appelle "acier". Il existe d’autres métaux à base de fer qui ne sont pas des aciers comme les fontes et les ferronickels par exemple.
Anticorrosifs
Anticorrosion
Caractérisation
Charbon
Eau salée
Epoxydes
Extraction par solvant
Isocyanate de phénol
Métaux -- Revêtements protecteurs
Polyuréthanes
Revêtements organiques
Test d'immersionIndex. décimale : 667.9 Revêtements et enduits Résumé : Solvent extraction of subbituminous coal at mild conditions (360°C) provides solid extracts that consist of numerous organic molecules that can be utilized in the synthesis of polymeric coatings. We describe the extraction process as well as the application of the resultant materials, which bear phenolic groups as the main reactive functionality, for the synthesis of polyurethane and epoxy coatings. The respective reactions of coal extract with isocyanates or epoxides were validated by 13C-NMR. By combining 50–67% coal extract with suitable, flexible co-reactants and co-resins, we formulated coatings with excellent wet adhesion to aluminum, flexibility, and corrosion protection with the same quality as reference coatings. The work is an advancement toward the goal of developing economic and resource-efficient routes from coal to polymers with attractive properties, where coal extracts can compete with petrochemically derived raw materials. Note de contenu : - METHODS AND MATERIALS : Coal extraction - Coating raw materials - Coating preparation and application - Characterization
- RESULTS AND DISCUSSION : Coal extraction - Coal extract characterization - Coal extract solubility - Coatings applying tetralin insoluble coal extract TI - Coatings applying tetralin-soluble coal extract TS - Health and environmental hazards
- Table 1 : Elemental analysis of coal and coal extracts
- Table 2 : Hydroxy (OH) group analysis by derivatization and 31P-NMR24
- Table 3 : Model reactions with phenyl isocyanate
- Table 4 : Model reactions with butyl glycidyl ether (BuGlyEther) heated 1.5 h to 160°C in a pressure bomb
- Table 5 : PU coating based on TI coal extract
- Table 6 : Coal extract PU coatings with thermoplastic, tacky P
- Table 7 : Coal extract-based epoxy coatings with standard resins, all cured 1 h at 160°C
- Table 8 : Coal-extract-based epoxy coatings with flexible resins, all cured 1 h at 160°C
- Table 9 : Saltwater immersion of coated steel coupons (1 week at 20°C) with evaluation according to ASTM D714-02 (blistering) and ASTM D1654 (rust creepage) on two specimen per coating
- Table 10 : Coatings applying extract TS as filler. All coatings cured 5 days at ~ 20°CDOI : https://doi.org/10.1007/s11998-020-00457-7 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-020-00457-7.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35940
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