Dépouillements

Formulation for the properties/structure relationship studies on leather dyestuffs / J. Berenguer in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIV, N° 2 (02-03/1999)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCIV, N° 2 (02-03/1999) . - p. 43-50 Titre : Formulation for the properties/structure relationship studies on leather dyestuffs Type de document : texte imprimé Auteurs : J. Berenguer, Auteur ; J. Rocas, Auteur ; M. Dien, Auteur Année de publication : 1999 Article en page(s) : p. 43-50 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The development of a new range of dyestuffs requires a large amount of both synthetic and application work. In order to reduce the number of experiments, it was necessary to develop tools that can give in advance an idea about some properties of the designed dyestuffs. Based on previous theoretical studies, an empirical formula was used to develop a new range of compatible dyestuffs with high fastness. This formula defined the socalled WHAI value, which is obtained by the divison of the molecular weight by the number of azo and ionic groups and the hydrophobicity of the dye. This approach is useful for synthesizing both metal and non metal complex dyes. The new dyes were screened with spectrophotometric measurements, dyeing on leather fibres, physical property measurements (solubility, stability to acids and alkalis...), leather dyeings, fastness and range combinability. Results shown in a previous communication are expanded with three new dyes, one of them being a non-metal complex. The application results showw the ability of the new range to obtain almost all the possible shades in deep, level dyeings. Note de contenu : - Properties/Structure relationship - Dye synthesis En ligne : https://drive.google.com/file/d/1HaMgGNxcXharMCRZ0mMk-0dI8--tuHE7/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4487 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
006972	-	Périodique	Bibliothèque principale	Documentaires	Disponible

Viscometric assay of the protease activity of bate and drum liquor / S. M. Mozersky in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIV, N° 2 (02-03/1999)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCIV, N° 2 (02-03/1999) . - p. 51-58 Titre : Viscometric assay of the protease activity of bate and drum liquor Type de document : texte imprimé Auteurs : S. M. Mozersky, Auteur ; David G. Bailey, Auteur ; Jill Deiss, Auteur Année de publication : 1999 Article en page(s) : p. 51-58 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A viscometric procedure has been developed for the assay of general (non-specific) proteolytic activity of bate in the drum during the course of the bating operation. The basic features of the assay procedure are as follows : (1) a commercially available gelatin is used as substrate, (2) a clarified sample of drum liquor is added, (3) the resulting mixture is incubated at 40°C for 20 min or 60 min, (4) enzymatic activity is terminated with a stop reagent, and (5) the viscosity of the resulting solution is measured at 40°C. Any one of variety of instruments may be used to measure the viscosity, including a simple glass viscometer of the Cannon-Fenske type. The dependence of the measured viscosity on the concentration of proteolytic enzyme is well described be a double exponential decay curve. Numerous samples can be run simultaneously (with staggering). Note de contenu : - MATERIALS AND METHODS : Equipment - Solids and solutions - Sample preparation - Incubation - Measurement of viscosity - RESULTS AND DISCUSSION : Time course of gelatin hydrolysis - Dependence of viscosity on enzyme concentration - Preliminary application of the assay procedure - Calculations En ligne : https://drive.google.com/file/d/1mkaYpxB2vZ376iZdkcgooU92nr3Wqu_o/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4488 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
006972	-	Périodique	Bibliothèque principale	Documentaires	Disponible

Effects of neutral salts on collagen structure and chromium-collagen interactions / Eleanor M. Brown in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCIV, N° 2 (02-03/1999)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCIV, N° 2 (02-03/1999) . - p. 59-67 Titre : Effects of neutral salts on collagen structure and chromium-collagen interactions Type de document : texte imprimé Auteurs : Eleanor M. Brown, Auteur Année de publication : 1999 Article en page(s) : p. 59-67 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Tanning, the multi-step process whereby complex salts of Cr(III) crosslinking collagen fibrils, is more an art form than a science and the mechanism of the chromium-collagen interaction is poorly understoos. The long range goal of this research is to develop an experimental model with which to study the interactions of Cr(III) with collagen that are characteristic of tanning. In the present study, the thermal stability of acid soluble collagen from bovine skin is studied by circular dichroism spectropolarimetry. The melting curve for the triple helix of calf skin collagen in 0.05 M acetic acid was analyzed in terms of a pre-transition followed by complete denaturation, with a characteristic Tp=34.0°C Td=40.7°C. For pepsin solubilized, adult bovine dermal collagen, slightly lower denaturation temperatures were observed - Tp=31.0°C, Td=37.7°C probably due to the removal of the nonhelical telopeptides in the solubilization of adult skin collagen. The addition of salts, NaCl or KCl, initially had a destabilizing effect on the triple helix, lowering both Tp and Td nearly in parallel. At low concentrations of Nacl, preferential binding occured with apparent dissociation constants Kd(Tp)=0.034 M and K(Td)=0.017 M for calf skin collagen at 1 mg/mL in 0.05 M acetic acid, suggesting the possibility of site preferential interactions contributing to the observed melting behavior. As the salt concentration was increased between 0.1 M and 0.5 M, little further destabilization was observed, Tp and Td became indistinguishable. At 0.4 M NaCl (0.5 M KCl)the samples began to gel. Here, water-structuring effects may play a role. In contrast, under conditions of the model tanning system, where Cr(III) was added at pH 2 and the pH was then adjusted to 4.5 with bicarbonated, the "tanned" collagen gelled at a salt concentration of 0.1 M. Note de contenu : - EXPERIMENTAL : Materials - Spectroscopy - Simulated tanning procedure - RESULTS : Characterization of soluble collagen - Effects of salts - Simulated tanning En ligne : https://drive.google.com/file/d/10YW7UOTUD3Ga7f-kWr2fVXz-7Xsp_wEj/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=4489 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
006972	-	Périodique	Bibliothèque principale	Documentaires	Disponible