Dépouillements

Changes in hydrothermal stability of collagen with several catechin-metal compounds : A DSC study / Chen Hui in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 92, N° 3 (05-06/2008)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 92, N° 3 (05-06/2008) . - p. 93-95 Titre : Changes in hydrothermal stability of collagen with several catechin-metal compounds : A DSC study Type de document : texte imprimé Auteurs : Chen Hui, Auteur ; Shan Zhi-Hua, Auteur Année de publication : 2008 Article en page(s) : p. 93-95 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse thermique Catéchine La catéchine est une molécule de la famille des flavonoïdes de la sous-classe des flavanols. Elle est aussi connue sous le nom de catéchol, avec le risque de confusion avec le pyrocatéchol parfois dénommé lui aussi catéchol. L’usage dans la communauté scientifique a fini par imposer le terme de catéchine, dérivé du terme anglais catechin. Initialement découverte dans les fruits de l'acacia à cachou (Acacia catechu) duquel elle dérive son nom, la catéchine et ses nombreux isomères sont de puissants antioxydants qui aident à prévenir les maladies inflammatoires et coronariennes. Le terme de catéchine est aussi parfois utilisé pour désigner la classe des flavanols (flavan-3-ols, flavan-3,4-ols et leurs esters galliques). Pour éviter la confusion entre la classe et le composé, ce dernier est désigné dans ce contexte par (+/-)-catéchine. Collagène Ions métalliques Stabilité hydrothermale Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Differential scanning calorimetry (DSC) is a very useful tool to research the hydrothermal stability of collagen which has also been defined in the leather industry as denaturation temperature (Td). It has been widely used to describe the tanning power of materials, according to changes of Td. In this paper, changes in hydrothermal stability of collagen with several catechin-metal compounds were described using DSC curves. The Td results lead us to conclude that the hydrothermal stability of collagen can be improved by compounds formed with catechin and metal ions (Cr(III), Al(III) and Cu(II)).The more stable the compound, the higher the Td of collagen tanned with the compound ie.the stronger the tanning power of the compound and the higher the hydrothermal stability of collagen. En ligne : https://drive.google.com/file/d/1Tcwx3w0sW7caBzzr2bgT6rrxXAgeVG6N/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38952 [article]

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité
aucun exemplaire

Cross-linked polymers for aqueous finishing. Binders crosslinked with polyaziridin. Part. 1 : Behaviour of polyurethane in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 92, N° 3 (05-06/2008)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 92, N° 3 (05-06/2008) . - p. 96-102 Titre : Cross-linked polymers for aqueous finishing. Binders crosslinked with polyaziridin. Part. 1 : Behaviour of polyurethane Type de document : texte imprimé Année de publication : 2008 Article en page(s) : p. 96-102 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Finition Formulation (Génie chimique) Liants en phase aqueuse Polyéthylèneimine Polyuréthanes Résistance à l'abrasion Réticulants Revêtements en phase aqueuse Revêtements organiques Solidité de la couleur Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Aqueous finishing emerges as an alternative to solvent based finishes, which have to be limited due to their toxicity, negative effects on the environment and in terms of safety. It is necessary, in order to be able to introduce aqueous systems progressively, to use cross-linkers that react with polymers. Otherwise, it is not possible to obtain the physical properties required for most leather goods. The present study aims to look into the behaviour of polyurethane binders cross-linked with polyaziridine : the amount of cross-linker used, the type of polymer employed, the type of tannage and retannage effected and the evolution of the reaction over time. A comparison of results shows that the type of tannage and retannage, as well as the physical characteristics of the polyurethane used are influential factors in the behaviour of polyurethane binders cross-linked with polyaziridine. Different amounts of polyaziridine are needed with regard to the type of tannage and retannage effected and to the physical characteristics of the polyurethane used. Note de contenu : - Chemical products - Methodology - Table 1 : Physical characteristics of the polyurethane binders - Table 2 : Coating formulation - Table 3 : Results of colour fastness to dry rubbing - Table 4 : Results of colour fastness to wet rubbing En ligne : https://drive.google.com/file/d/1RXtnSVbt5AcIo_FcnmplkihJ5LMM34iP/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38953 [article]

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité
aucun exemplaire

Evaluation of environmental impact of typical leather chemicals. Part 3 : Biodegradability of vegetable tannin extracts by activated sludge / Qiang He in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 92, N° 3 (05-06/2008)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 92, N° 3 (05-06/2008) . - p. 103-106 Titre : Evaluation of environmental impact of typical leather chemicals. Part 3 : Biodegradability of vegetable tannin extracts by activated sludge Type de document : texte imprimé Auteurs : Qiang He, Auteur ; Danhong Sun, Auteur ; Xin Liu, Auteur ; Lin Wei, Auteur ; Bi Shi, Auteur Année de publication : 2008 Article en page(s) : p. 103-106 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Biodégradation Boues résiduaires -- Analyse Cuirs et peaux -- Industrie -- Aspect de l'environnement Déchets industriels -- Elimination Environnement -- Etudes d'impact Tanins végétaux Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The short-term (5 day) and long-term (30 day) biodegradation behaviours of black wattle, bayberry, valonia and chestnut tannin extracts were systematically investigated in this paper. The results indicated that all of these four vegetable tannin extracts are biodegradable although they might retard the biodegradation process to some extent owing to the inhibitory effect of tannins on the activated sludge process. Short-term biodegradabilities of the four tannin extracts were concentration-dependent. These tannin extracts could be effectively biodegraded in 5 days at concentrations of 0.25g/L, but the biodegradation process was retarded remarkably when the concentrations were increased to 5.00g/L. In general, short-term biodegradabilities of the four tannin extracts follow the sequence of valonia tannin>chestnut tannin>bayberry tannin>wattle tannin, implying that the hydrolysable tannins are easier to biodegrade than the condensed tannins. The results of long-term biodegradation showed that all of the four vegetable tannin extracts can be completely biodegraded by prolonging the activated sludge process, even if they are present at high concentration. Therefore, the encouraging findings in this research suggest that vegetable tannin extracts are environmentally friendly leather chemicals. Note de contenu : - BOD5/COD values of vegetable tannin extracts - Respiration of activatedslud ge in the presence of vegetable tannin extracts - COD removals of vegetable tannin extracts by the activatedslud ge process - COD removals (%) of vegetable tannin extracts at different concentrations - Table 1 : Type andtannin content of vegetable tannin extracts tested in experiments - Table 2 : BOD5 /COD values of vegetable tannin extracts at different concentrations En ligne : https://drive.google.com/file/d/1rkdcAB3YoMjEm3urqqTf-HjnXnzkK-x3/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38954 [article]

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité
aucun exemplaire

Fluorine-containing aqueous copolymer emulsion for waterproof leather / Zhaoyang Luo in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 92, N° 3 (05-06/2008)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 92, N° 3 (05-06/2008) . - p. 107-113 Titre : Fluorine-containing aqueous copolymer emulsion for waterproof leather Type de document : texte imprimé Auteurs : Zhaoyang Luo, Auteur ; Haojun Fan, Auteur ; Lu Yan, Auteur ; Bi Shi, Auteur Année de publication : 2008 Article en page(s) : p. 107-113 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caractérisation Copolymères Cuirs et peaux -- Finition Emulsions Fluoropolymères Imperméabilisation Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A novel fluorine-containing aqueous copolymer emulsion, which was used for waterproof leather fatliquoring, was prepared via free radical copolymerization from maleic anhydride and natural oil (rapeseed oil and fish oil) followed by an esterification reaction with dodecafluoro heptanol and octadecyl alcohol. The reaction was monitored on-line by FTIR analysis and the combining fastness [strength of the combination] between the fatliquoring agent and leather fibre was examined by extraction with dichloromethane and water. Simultaneously, the effects of the fluorine content on contact angle (water-surface of leather), dynamic waterproofness time and static water absorption ratio of leather were also investigated. The X-ray photoelectron spectroscopy (XPS) showed that most of the hydrophobic fluorine-containing groups were orientated onto the surface of the leather and formed a hydrophobic film layer, whilst the hydrophilic carboxyl groups were enveloped in the inner layer. The fact the combination fastness is greater for the fluorine-containing copolymer than for other types of fatliquoring agents, shows that the carboxyl groups in the inner layer have coordinated with chrome(III) in the form of chemical bonding rather than by physical absorption. Chrome tanned leather treated with this type of fluorine-containing copolymer fatliquoring agent shows good durable waterproofness. When the fluorine content in fatliquoring agent is varied from 0wt% to 5wt% (based on solid content), the contact angle increases from 125° to 155°, the static water absorption ratio of leather is less than 9wt% and the dynamic waterproofness time reaches 55 minutes. Note de contenu : - MATERIALS AND METHOS : Materials - Preparation of fluorine-containing copolymer aqueous emulsion - The application of fatliquoring agent - Characterizations - RESULTS AND DISCUSSION : The on-line FTIR analysis of the synthesis - The combination fastness between the fatliquoring agent and collagen fibre - The fluorine concentration on the surface of leather - The effect of the fluorine content on contact angle of the leather - The waterproofness of leather - The possible waterproof mechanism of leather - Table 1 : Process for upper leather with fluorine-containing fatliquoring agent - Table 2 : Special groups and the FTIR adsorption peaks - Table 3 : Content of substances soluble in dichloromethane and water - Table 4 : Concentration of surface elements of leathers A and B En ligne : https://drive.google.com/file/d/1r5NeKZSaMIILBIKbGaf98X3sxxQfNsUj/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38955 [article]

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité
aucun exemplaire

Deliming with weak acid-effects on leather quality and effluent / S. M. Colak in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 92, N° 3 (05-06/2008)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 92, N° 3 (05-06/2008) . - p. 120-123 Titre : Deliming with weak acid-effects on leather quality and effluent Type de document : texte imprimé Auteurs : S. M. Colak, Auteur ; Eylem Kiliç, Auteur Année de publication : 2008 Article en page(s) : p. 120-123 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Acides Ammonium Cuirs et peaux -- Analyse Cuirs et peaux -- Propriétés physiques Cuirs et peaux de moutons Déchaulage Opération consistant à débarrasser les peaux de la chaux et des substances alcalines qui leur ont été appliquées au pelanage. Eaux usées -- Analyse Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Effluent which has a high ammonium content is produced as a result of traditional deliming operation using ammonium salts. Ammonia is converted into nitrate by the nitrogen cycle in nature and ammonium salts discharged into natural water sources have toxic effects on living organisms.In this research weak acids were used to delime in studies on sheep skins to reduce the ammonium load that originates from deliming. Beside the deliming effect of acids, the N content of the resulting discharge water was determined and the effect of these methods on the quality of the leather was studied. The data obtained from the study were compared with the traditional deliming methods and standards. Note de contenu : - Table 1 : Deliming procedure - Table 2 : Degreasing, pickling, tanning, neutralisation and dyeing procedures - Table 3 : Total nitrogen values of deliming effluents - Table 4 : Chemical analysis results of leathers processed using different deliming methods - Table 5 : Physical test results of leathers processed usingdiffer ent deliming methods En ligne : https://drive.google.com/file/d/1d6Ab5ISYhVt5M-CDc1c-dDyuShxmJksX/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38956 [article]

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité
aucun exemplaire

Determination of chromium(VI) with bordeaux red by flow injection spectrophotometry in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 92, N° 3 (05-06/2008)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 92, N° 3 (05-06/2008) . - p. 1 Titre : Determination of chromium(VI) with bordeaux red by flow injection spectrophotometry Type de document : texte imprimé Année de publication : 2008 Article en page(s) : p. 1 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse quantitative (chimie) Chimie analytique Chrome hexavalent Eaux usées -- Teneur en chrome hexavalent Oxydation Rouge (couleur) Spectrophotométrie Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : A new flow injection spectrophotometric method for determination of chromium(VI) in tannery wastewater is introduced. The proposed method is based on the oxidation of bordeaux red by chromium(VI) in acidic media. The absorbance was registered at 520nm. Under the optimum conditions, the linear range for chromium(VI) was 0.10-10.0mg/L. The detection limit was 0.02mg/L. The relative standard deviation (n = 11) for 2.0 mg/L chromium(VI) was 1.37 %. This method is simple, accurate, sensitive and rapid. The method was applied to the determination of chromium(VI) in tannery wastewater with satisfactory results. Note de contenu : - EXPERIMENTAL PROCEDURE : Chemical reagents - ANALYTICAL PROCEDURE - RESULTS AND DISCUSSION : Choice of wavelength - Effect of flow injection variables - Effect of chemical reaction variables - Calibration curve, reproducibility and detection limit - Effects of foreign ions - Analysis of the samples - Table 1 : Determination of chromium(VI) in tannery wastewater En ligne : https://drive.google.com/file/d/1nk1YajZwVWv32Z7fLvpM-ZaRoICa4rQ-/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38957 [article]

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité
aucun exemplaire

On-line determination of tannic acid in leather wastewater by flow injection spectrophotometry / Wei Liang in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 92, N° 3 (05-06/2008)

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 92, N° 3 (05-06/2008) . - p. 127-129 Titre : On-line determination of tannic acid in leather wastewater by flow injection spectrophotometry Type de document : texte imprimé Auteurs : Wei Liang, Auteur ; Zhang Xinshen, Auteur ; Huang Jin, Auteur ; Xie Yonghong, Auteur ; Xiao Kai, Auteur Année de publication : 2008 Article en page(s) : p. 127-129 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse quantitative (chimie) Cuirs et peaux Eaux usées -- Analyse Spectrophotométrie Tanins Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A rapid, simple, reliable and automatic method was proposed for on-line determination of tannic acid in leather wastewaters. Based on the tannic acid reduction of phosphotungstic acid to form a blue compound in pH12.38 alkaline solutions, the shade of the blue compound is in a linear relation to the content of tannic acid at the maximum absorption peak of 700nm. The optimal experimental conditions have been obtained. The linear range of the proposed method was between 200μg L-1 to 50mg L-1. The relative standard deviation was 3.21% and 2.06% for 500μg L-1 and 20mg L-1 of tannic acid standard solution respectively (n = 10). The method had been successfully applied to determination of tannic acid in leather wastewater samples and the analytical results were satisfactory. Note de contenu : - EXPERIMENTAL PROCEDURE : Chemical regents - Apparatus - Preparation of solution - ANALYTICAL PROCEDURE - RESULTS AND DISCUSSION : Choice of the detection wavelength - Effect of flow rate - Effect of phosphotungstic acid reagent solution (R1) - Effects of pH - Effect of the reaction coil length - Effect of sample volume - Effects of foreign ions - Linearity and precision of the proposed method - Application - Table 1 : Determination of tannic acid in leather wastewater by the proposed method Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38958 [article]

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité
aucun exemplaire