Action of pancreatin on residual epidermis of goatskin-examination via histological changes during bating / Ding Haiyan in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 89, N° 4 (07-08/2005)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 89, N° 4 (07-08/2005) . - p. 141-144 Titre : Action of pancreatin on residual epidermis of goatskin-examination via histological changes during bating Type de document : texte imprimé Auteurs : Ding Haiyan, Auteur ; Liegang Sun, Auteur ; Liang Chengjian, Auteur Année de publication : 2005 Article en page(s) : p. 141-144 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Confitage Le confitage est une action biochimique effectuée au moyen de produits enzymatiques, qui a pour but de dégrader les fibres élastiques, contribuant ainsi à augmenter la souplesse du cuir. En outre, les enzymes complètent la dégradation des résidus épidermiques, donnant ainsi une fleur plus propre et plus lisse. Cuirs et peaux -- Analyse Cuirs et peaux de chèvres Epiderme Pancréatine Peau -- Histologie Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The histological changes of the epidermis of goatskin under different bating conditions were observed at the ultrastructure level by TEM and SEM. The results showed that the residual epidermal matter was obviously removed from the surface of delimed pelt by pancreatin in the normal bating process and this action will be strengthened by both an increase of the amount of pancreatin and by prolonging the bating time. Evidence is provided of the function of pancreatin in bating, eliminating scud and clarifying the grain surface. Note de contenu : - Sample preparation - Sampling and fixation - Specimen preparation for TEM - Specimen preparation for SEM En ligne : https://drive.google.com/file/d/1QycDHpTwbj8x1N0qDVsipv-7Dub3lvSU/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39244 [article]

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Effects of different silicon-based surface active additives on degradability of clearcoats exposed to bird dropping / Bahram Ramezanzadeh in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 11, N° 4 (07/2014)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 11, N° 4 (07/2014) . - p. 533-543 Titre : Effects of different silicon-based surface active additives on degradability of clearcoats exposed to bird dropping Type de document : texte imprimé Auteurs : Bahram Ramezanzadeh, Auteur ; Mohsen Mohseni, Auteur ; N. Naseh, Auteur Année de publication : 2014 Article en page(s) : p. 533-543 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Analyse thermomécanique dynamique Angle de contact Automobiles -- Vernis Copolymère acrylique mélamine Copolymère silicone acrylate Déjections d'oiseaux Fourier, Spectroscopie infrarouge à transformée de Microscopie à force atomique Microscopie électronique à balayage Pancréatine Polydiméthylsiloxane Le polydiméthylsiloxane —[O-Si(CH3)2]n—, ou poly(diméthylsiloxane) selon la nomenclature systématique, communément appelé PDMS ou diméthicone, est un polymère organominéral de la famille des siloxanes souvent présent dans les shampoings. On l'y ajoute pour augmenter le volume des cheveux mais il peut également aller boucher les pores du cuir chevelu et rendre les cheveux gras. C'est une des raisons pour lesquelles se laver les cheveux tous les jours est très déconseillé avec un shampooing contenant des silicones. Il existe également de l'amodiméthicone, qui est un dérivé du diméthicone. Le polydiméthylsiloxane est un additif alimentaire (E900), utilisé comme antimoussant dans les boissons (Coca-Cola BlāK). La chaîne de poly(diméthylsiloxane) forme également la structure de base des huiles et des caoutchoucs silicones. Résistance chimique Vernis -- Additifs Index. décimale : 667.9 Revêtements et enduits Résumé : A series of clearcoats separately loaded with different concentrations of functional silicon–polyacrylate and polydimethyl siloxane additives were prepared. Optical performances of the cured films were studied by gonio-spectrophotometry. Dynamic mechanical thermal analysis was used in order to investigate viscoelastic properties of the additive-containing films. Contact angle measurements, (FTIR) spectroscopy, scanning electron microscopy equipped with energy-dispersive analysis of X-ray, and atomic force microscopy techniques were utilized to evaluate surface properties of the clearcoats. It was shown that clearcoat surface free energy decreased and its crosslinking density increased in the presence of the additives. Results revealed that addition of both additives to the clearcoat enhanced its resistance against pancreatin (simulated bird droppings). A decrease in surface degradation was observed in the presence of the additives. Results also showed that functional polydimethyl siloxane influenced coating viscoelastic, surface chemistry, and biological resistance more effectively compared to that of the functional silicon–polyacrylate one. Note de contenu : - EXPERIMENTAL : Materials and sample preparation - Testing methods - RESULTS AND DISCUSSION : Appearance of the clearcoats loaded with additives - FTIR studies - DMTA analysis - Surface analysis DOI : 10.1007/s11998-014-9572-0 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-014-9572-0.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21714 [article]

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A mechanistic study of degradation of a typical automotive clearcoat caused by bird droppings / Hossein Yari in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 8, N° 1 (01/2011)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 8, N° 1 (01/2011) . - p. 83-95 Titre : A mechanistic study of degradation of a typical automotive clearcoat caused by bird droppings Type de document : texte imprimé Auteurs : Hossein Yari, Auteur ; Mohsen Mohseni, Auteur ; Bahram Ramezanzadeh, Auteur Année de publication : 2011 Article en page(s) : p. 83-95 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Automobiles -- Vernis Déjections d'oiseaux Hydrolyse Pancréatine Revêtements -- Détérioration Vernis -- Détérioration Index. décimale : 667.9 Revêtements et enduits Résumé : This study aims at investigating the degradation mechanism of an automotive clearcoat caused by bird droppings. Natural bird droppings and their synthetic equivalent (pancreatin) were utilized for this purpose. The presence of highly-etched areas on the surface of coatings and structural variations of clearcoat after being attacked by these materials corresponded to a catalyzed hydrolytic degradation. This finding was obtained using different analytical techniques. Based on these studies, three possible hypotheses were presented, including acid catalysis, metal ion catalysis, and enzymatic catalysis. The conditions required for the occurrence of each hypothesis were discussed. It was found that acid and metal ions have a weak contribution to catalyze the hydrolysis reaction of clearcoat, whereas enzymes existing in bird droppings were mainly responsible for this hydrolytic degradation. DOI : 10.1007/s11998-010-9273-2 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-010-9273-2.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10926 [article]

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Review : Degradation of automotive clear coat caused by bird droppings / Balkrushna Dahatonde in PAINTINDIA, Vol. LXX, N° 11 (11/2020)  

[article]  inPAINTINDIA > Vol. LXX, N° 11 (11/2020) . - p. 78-90 Titre : Review : Degradation of automotive clear coat caused by bird droppings Type de document : texte imprimé Auteurs : Balkrushna Dahatonde, Auteur ; Manoj Kadam, Auteur ; Sachin Gupta, Auteur Année de publication : 2020 Article en page(s) : p. 78-90 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Automobiles -- Vernis Détérioration enzymatique Fientes d'oiseaux Hydrolyse Pancréatine Index. décimale : 667.9 Revêtements et enduits Résumé : This review paper aims at investigating the degradation mechanism of an automotive clear coat caused by bird droppings. Natural bird droppings and their synthetic equivalent (pancreatin) were utilized for this purpose. The presence of highly etched areas on the surface of coatings and structural variations of clear coat after being attacked by these materials corresponded to a catalyzed hydrolytic degradation. This finding was obtained using different analytical techniques. Based on these studies, three possible hypotheses were presented, including acid catalysis, metal ion catalysis, and enzymatic catalysis. The conditions required for the occurrence of each hypothesis were discussed. It was found that acid and metal ions have a weak contribution to catalyze the hydrolysis reaction of clear coat, whereas enzymes existing in bird droppings were mainly responsible for this hydrolytic degradation. Note de contenu : - EXPERIMENTAL : Coating preparation - Biological materials - Biological tests - CHARACTERIZATION - RESULTS AND DISCUSSION : Microscopic evaluations - Acid catalyzed hydrolysis - Catalysis by metal ions - Enzymatically-induced hydrolysis - Fig. 1 : Typical defect features of an automotive clear coat influenced by bird droppings and pancreatin - Fig. 2 : Specifications of a multilayer automotive system - Fig. 3 : Optical and AFM images of clear coat surface before and after exposure to various conditions - Fig. 4 : FTIR spectra of clear coat before and after exposure to various conditions : a) before any exposure, b) after 300 h exposure to pancreatin and weathering, c) after 300 h exposure to bird-dropping and weathering and d) after 300 h exposure to only weathering - Fig. 5 : EDS spectra of a) intact and degraded area caused by b) bird dropping, c) pancreatin - Fig. 6 : Shows the FTIR and XRF analyses of bird droppings and pancreatin - Fig. 7 : Degradation mechanism of a typical acrylic melamine caused by bird droppings or pancreatin - Fig. 8 : Optical and scanning electron microscopic images of damaged surface of clearcoat at different temperatures - Fig. 9 : SEM images and EDS analysis of different points of degraded areas - Table 1 : Specification of pancreatin - Table 2 : The EDS results of pancreatin before and after repeated rinsing by DI water En ligne : https://drive.google.com/file/d/1ZalLXfidGTI7IHqxJS1uncjmJeWjtHuX/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35195 [article]

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The action of pancreatin on collagen fibres and interfibrillary substance during bating / Ding Haiyan in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 90, N° 2 (03-04/2006)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 90, N° 2 (03-04/2006) . - p. 47-53 Titre : The action of pancreatin on collagen fibres and interfibrillary substance during bating Type de document : texte imprimé Auteurs : Ding Haiyan, Auteur ; Liang Chengjian, Auteur Année de publication : 2006 Article en page(s) : p. 47-53 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chimie analytique Collagène Confitage Le confitage est une action biochimique effectuée au moyen de produits enzymatiques, qui a pour but de dégrader les fibres élastiques, contribuant ainsi à augmenter la souplesse du cuir. En outre, les enzymes complètent la dégradation des résidus épidermiques, donnant ainsi une fleur plus propre et plus lisse. Cuirs et peaux de chèvres Hydrolyse Hydroxyproline Pancréatine Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In order to illustrate the functions of pancreatin in the bating process during leather manufacture, we used TEM and SEM to observe the histological changes of collagen fibres of goatskin at the ultrastructural level under different bating conditions. Chemical analysis was simultaneously used to illustrate the action of pancreatin on interfibrillary substance and collagen protein. The results showed that the interfibrillary substance was removed and the collagen fibre structure was moderately opened-up under normal bating conditions. The removal of the interfibrillary substance aids in the opening-up of the collagen fibre structure. Pancreatin has an obvious hydrolytic effect on mucin, mucoid and collagenous substance too. Excessive concentrations of pancreatin are beneficial to the removal of non-fibrous substance, i.e., the interfibrillary substance but, this excessive treatment can cause loss of collagen protein and damage of the collagen fibres making the collagen fibre structure over opened-up. Thus in conditions with excess pancreatin, the final result may be leather with an empty handle. This study provides a basis of ultrastructure and serves as scientific guidance for selection of chemicals and technique design for goat shoe upper leather manufacture and offers a reference to other related studies. Note de contenu : - EXPERIMENTAL METHODS : Sample preparation - Sampling and fixation - Specimen preparation for TEM and SEM - Determination of hydroxy-proline - Determination of reducing sugar(R.S.) - RESULTS AND DISCUSSION : The removal of the interfibrillary substance during the bating process - Comparison of the opening-up of the collagen fibre structure and change of collagenous fibrils under various - The hydrolyzing effect of pancreatin on collagenous substance bating systems - Table 1 : Bating scheme - Table 2 : The R.S. hydrolyzed from skin during the different bating process - Table 3 : The quantity of hydroxyproline in the liquors after bating process En ligne : https://drive.google.com/file/d/1LuTBW1LRMkRp_DFx43EjM--trENxKJ7M/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39156 [article]

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