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Polyanionic bio-emulsifier : a heteropolysaccharide based bio-composite for leather post tanning process / Sharmila Selvaraju in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIV, N° 3 (03/2019)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIV, N° 3 (03/2019) . - p. 72-79 Titre : Polyanionic bio-emulsifier : a heteropolysaccharide based bio-composite for leather post tanning process Type de document : texte imprimé Auteurs : Sharmila Selvaraju, Auteur ; Sathya Ramalingam, Auteur ; Jonnalagadda Raghava Rao, Auteur Année de publication : 2019 Article en page(s) : p. 72-79 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Agents de tannage Biomatériaux Biopolymères Composites Cuirs et peaux Emulsifiants Polysaccharides Les polysaccharides (parfois appelés glycanes, polyosides, polyholosides ou glucides complexes) sont des polymères constitués de plusieurs oses liés entre eux par des liaisons osidiques. Les polyosides les plus répandus du règne végétal sont la cellulose et l’amidon, tous deux polymères du glucose. De nombreux exopolysaccharides (métabolites excrétés par des microbes, champignons, vers (mucus) du ver de terre) jouent un rôle majeur - à échelle moléculaire - dans la formation, qualité et conservation des sols, de l'humus, des agrégats formant les sols et de divers composés "argile-exopolysaccharide" et composites "organo-minéraux"(ex : xanthane, dextrane, le rhamsane, succinoglycanes...). De nombreux polyosides sont utilisés comme des additifs alimentaires sous forme de fibre (inuline) ou de gomme naturelle. Ce sont des polymères formés d'un certain nombre d'oses (ou monosaccharides) ayant pour formule générale : -[Cx(H2O)y)]n- (où y est généralement x - 1). On distingue deux catégories de polysaccharides : Les homopolysaccharides (ou homoglycanes) constitués du même monosaccharide : fructanes, glucanes, galactanes, mannanes ; les hétéropolysaccharides (ou hétéroglycanes) formés de différents monosaccharides : hémicelluloses. Les constituants participant à la construction des polysaccharides peuvent être très divers : hexoses, pentoses, anhydrohexoses, éthers d'oses et esters sulfuriques. Selon l'architecture de leur chaîne, les polysaccharides peuvent être : linéaires : cellulose ; ramifiés : gomme arabique, amylopectine, dextrane, hémicellulose et mixtes : amidon. Post-tannage Retannage Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Biopolymer-based composites are attracting significant interest in leather processing due to their incremental substitution of petrochemical products as raw materials in the retanning stage. Several polymeric bio-composites were developed and studied as alternatives to synthetic tanning agents (syntans). Bio-composite was prepared by simultaneously dispersing cellulose (acting as syntan) and emulsifying soybean oil with a bio-emulsifier termed Emulsan (acting as fatliquor). The resultant dual propertied of fullness and softness is endowed as a leather supplement to reduce the negative impact on the environment. Hence polymeric bio-composites were prepared through ultrasonication by blending different amounts of cellulose with soybean oil with an optimised Emulsan ratio. In order to enhance the biocompatibility of this bio-composite, the Emulsan surfactant we chose was extracted from Acinetobacter calcoaceticus. The poly-anionic nature of Emulsan serves as a stable surfactant to emulsify soybean oil into cellulose in the composite preparation. The resultant composites were characterised for functionality and physical properties by FTIR, DSC, TGA, and DLS. The value of an example composite in leathers’ post tanning processes was evaluated by utilising it as a retanning agent. Leather treated with a bio-polymeric composite showed improved strength and physical properties versus control leathers. Note de contenu : - MATERIALS AND METHODS : Preparation of emulsan medium preparation and growth conditions - Preparation of extra-cellular emulsan - Preparation of composites samples - Characterisation of prepared bio-composites - Application of composite as a retanning agent during leather post tanning process - Physical testing of the leather samples - RESULTS AND DISCUSSION : Characteristics of composite treated leather En ligne : https://drive.google.com/file/d/1lvynFi0y9G9EtFsCZqg91ON9abL4ISaP/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31927 [article]

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Polyacrylate ester-based polycarboxylate (PCE) as a new leather retanning agent / Miquel Canudas in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIV, N° 3 (03/2019)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIV, N° 3 (03/2019) . - p. 80-88 Titre : Polyacrylate ester-based polycarboxylate (PCE) as a new leather retanning agent Type de document : texte imprimé Auteurs : Miquel Canudas, Auteur ; Nicola Menna, Auteur ; Antoni Torrelles, Auteur ; Joan de Pablo, Auteur ; Josep Maria Morera, Auteur Année de publication : 2019 Article en page(s) : p. 80-88 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Agents de tannage Caractérisation Plastifiants Polyacryliques Polycarboxylates Polymères -- Synthèse Retannage Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Acrylic resins are extensively used as retanning products because of their affinity with chrome tanned leather. However, their anionicity changes the cationic leather surface becoming a problem for the subsequent uses of fatliquoring and dyeing agents. As a result of changing charges, a leather with lower color intensity and poorer structural properties is obtained. This paper presents an initial study which analyses the use of polyacrylates esters based polycarboxylates (PCE) superplasticizers as a new retaining agent compared to traditional wet end acrylic resins. Properties of PCEs in leather were compared to acrylic resins. For the applying assays, PCEs with different molecular weight were synthetized and characterized using a gel permeation chromatography (GPC). Experimental results indicate that PCEs improve leather properties avoiding the dyeing and fatliquoring problems of the acrylic resins. Note de contenu : - EXPERIMENTAL : Materials and chemicals - Equipment - Synthesis of the PCEs - Characterization - Retanning application - RESULTS AND DISCUSSION : PCEs synthesis - Retanning tests En ligne : https://drive.google.com/file/d/18u81LTsURJ9FyoecRPKKcdGnoowQNYdR/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31928 [article]

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Study on the microstructure of crocodylus niloticus skins during leather making process / Qiang Tao-Tao in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIV, N° 3 (03/2019)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIV, N° 3 (03/2019) . - p. 89-93 Titre : Study on the microstructure of crocodylus niloticus skins during leather making process Type de document : texte imprimé Auteurs : Qiang Tao-Tao, Auteur ; Han Mi-Mi, Auteur Année de publication : 2019 Article en page(s) : p. 89-93 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Crocodile du Nil Cuirs et peaux -- Analyse Microstructures -- Analyse Peau -- Histologie Wet-blue (tannage) Peau tannée au chrome (le chrome donne une couleur bleue) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The variation on the microstructure of Crocodylus niloticus skins in the tanning process was observed and analyzed by using frozen section staining, which provide the reliable theoretical basis for Crocodylus niloticus leather production. The research on aldehyde fuchshin staining method showed that elastic fiber will receive a lot of damage in the bating and bleaching process. Through the observation of wet blue leather by scanning electron microscopy, the preparation work section and tanning process design are reasonable, also, inter-fibrillary substances had been well removed. The crosscut microstructure of Crocodylus niloticus hides before and after fatliquoring was observed by nile blue sulphate staining method, and the results showed that fatliquor could penetrate into the skin uniformly. Note de contenu : - EXPERIMENTAL : Materials - Instruments - Leather making process - Sampling - Observation on microstructure of preparation and tanning section - Optical light microscope observation - Scanning electron microscope observation - RESULTS AND DISCUSSION : The variation of histology at preparation stage - the variation of elastic fibers at preparation stage - The histology of blue wet skins of crocodylus niloticus - The variation of histology before and after fatliquoring En ligne : https://drive.google.com/file/d/1FihZhQIpgWbw6oZQ511GYr85HhhhegdC/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31929 [article]

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Deciphering the role of individual retanning agents on physical properties of leathers / Murali Sathish in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIV, N° 3 (03/2019)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIV, N° 3 (03/2019) . - p. 94-102 Titre : Deciphering the role of individual retanning agents on physical properties of leathers Type de document : texte imprimé Auteurs : Murali Sathish, Auteur ; Bhuvana Subramanian, Auteur ; Jonnalagadda Raghava Rao, Auteur ; Nishad Fathima Nishter, Auteur Année de publication : 2019 Article en page(s) : p. 94-102 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Agents de tannage Biopolymères Copolymère mélamine-formaldéhyde Cuirs et peaux -- Propriétés physiques Phénoplastes Polyacryliques Retannage Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : In post-tanning different types of retanning agents are used in combination to improve the functional properties of leather and therefore understanding the individual effect of each retanning agents on final properties is difficult. This work mainly focuses toward quantifying the individual effect of different weight percentages (4, 8 and 16%) of phenol-formaldehyde resin (PFR), melamine-formaldehyde resin (MFR), acrylic resin (AR) and biopolymers (BP) on physical properties of leather. It was found that the strength characteristics are greatly affected when the retanning agents offer increased above 8% where the effect of phenol-formaldehyde resin is higher than other re-tanning agents. Melamine-formaldehyde resin and biopolymer is predominantly affecting the belly region. It has also been observed that the phenol-formaldehyde resin improves the fullness whereas grain tightness and flatness are improved with increasing the percentages of melamine-formaldehyde resin offer. Biopolymer improves the grain smoothness and the ability of improving the roundness of leather is similar for all kind of retanning agents. A meaningful conclusion could not be drawn in the porosity results obtained due to the heterogeneous nature of leather matrix. Thus, a conventional triplicate method of measurement as done in this study would not suffice to provide a conclusive interpretation of results obtained using capillary flow porometry technique. Note de contenu : - EXPERIMENTAL METHODOLOGY : Analysis of physical strength characteristics - Analysis of porosity - RESULTS AND DISCUSSIONS : effect of phenol-formaldehyde resin (PFR) on physical strength characteristics - Effect of melamine-formaldehyde resin (MFR) on physical strength characteristics - Effect of acrylic resin (AR) on physical strength characteristics - Effect of protein based biopolymer (BP) on physical strength characteristics - Effect of re-tanning agents on porosity - Effect of re-tanning agents on organoleptic properties En ligne : https://drive.google.com/file/d/1c7oRcD0zU0flHM8vo0i4mnnKr3Fp2TDF/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31930 [article]

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