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Comparative study of retanning properties of melamine-glyoxal resins produced by different sulfonating agents / Muhammad Naveed Ashraf in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 5 (09-10/2022)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 106, N° 5 (09-10/2022) . - p. 205-214 Titre : Comparative study of retanning properties of melamine-glyoxal resins produced by different sulfonating agents Type de document : texte imprimé Auteurs : Muhammad Naveed Ashraf, Auteur ; Shahzad Maqsood Khan, Auteur ; Shahid Munir, Auteur ; Rashid Saleem, Auteur Année de publication : 2022 Article en page(s) : p. 205-214 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Composés organiques -- Synthèse Cuirs et peaux -- Propriétés mécaniques Eaux usées -- Analyse Etudes comparatives Mélamine glyoxal Retannage Tannage synthétique Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Amino resins have many applications including leather retanning. Being condensation products of formaldehyde, amino resins are one of the sources of free formaldehyde in leather. ln this work novel glyoxylated melamine resins were produced to make formaldehyde-free leather. The optimised process of synthesis was used to produce stable resins which were able to polymerise further in situ at retanning pH conditions. Water solubility of the resins was achieved by using various aromatic sulfonating agents including, orthanilic acid (ONA), metanilic acid (MNA), sulfanilic acid (SNA) and aniline 2,5-disulfonic acid (ADS). Synthesised resins were used in leather retanning to evaluate their comparative mechanical properties, organoleptic properties, free formaldehyde content and SEM analysis. The effluent of each retanning bath was also analysed for pollution load studies. All the resins showed improvements in mechanical and organoleptic properties in comparison with a commercial melamine resin but, the novel resin MGSNA exhibited remarkable results. Estimation of free formaldehyde content showed absence of free formaldehyde content in leather and retanning effluent of all the novel resins. Determination of COD, TDS and TSS of effluent confirmed a significant reduction in pollution load due to improved exhaustion of resins attributed to their in-situ polymerisation in collagen fibres to enhance their fixation. SEM analysis of leather confirmed improvements in retanning results due to formation of more orderly arranged networks of collagen fibres. Moreover, the introduction of an aromatic ring in the resin structure resulted in improved thermal stability of the resins. The results indicate that this development is remarkable for production of formaldehyde-free leather with improved retanning properties along with reduction in water pollution. This work also addresses the carcinogenic effects of formaldehyde. Note de contenu : - EXPERIMENTAL PROCEDURE : Chemicals and apparatus - Synthesis of novel melamine-glyoxal resins - RESULTS AND DISCUSSION : Synthesis of resins - Leather applications of various novel glyoxal based melamine resins - Mechanical properties of leather reatanned with glyoxal-based melamine resins - Orgnoleptic properties of the leather retanned with glyoxal-based melamine resins - SEM analysis - Quantitative estimation of free formaldehyde content in retanned leather - Thermogravimetric analysis - Effluent analysis - Structural elucidation - Table 1 : Mole ratio and physical characteristics of prepared novel melamine resins - Table 2 : Leather processing materials, conditions and recipe - Table 3 : Mechanical properties of leather retanned with glyoxal based melamine resins - Table 4 : Comparative study of effluent produced from retanning baths of synthesised resins En ligne : https://drive.google.com/file/d/1d731nM2Y_RzuR-xX0DT3EX7AtII9e3uS/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38195 [article]

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Study on moisture permeability and microscopic analysis of two kinds of coated thin sheep leather / Zhong Anhua in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 5 (09-10/2022)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 106, N° 5 (09-10/2022) . - p. 215-217 Titre : Study on moisture permeability and microscopic analysis of two kinds of coated thin sheep leather Type de document : texte imprimé Auteurs : Zhong Anhua, Auteur ; Fang Songchun, Auteur ; Huang Zhuo, Auteur Année de publication : 2022 Article en page(s) : p. 215-217 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : acrylique, Acide L'acide acrylique ou acide acroléïque ou acide prop-2-énoïque est un composé organique de formule brute C3H4O2 et de formule semi-développée CH2=CHCOOH. C'est un acide carboxylique et un alcène vinylique, et se présente comme un liquide incolore à l'odeur âcre. L'acide acrylique et ses esters, les acrylates, sont utilisés dans la fabrication de matières plastiques, dans les peintures acryliques et dans divers autres polyacryliques qui ont de multiples usages. Cuirs et peaux -- Analyse Cuirs et peaux de moutons Humidité Microscopie Perméabilité Polyuréthanes Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : This paper focuses on the differences in moisture permeability of two types of coated thin sheep leather. Based on the macroscopic experimental data, the changes of moisture permeability of two kinds of coated thin sheep leather with time were analysed. Combined with molecular dynamics simulation, the reasons for the difference of moisture permeability between the two kinds of leather are analysed from the microscopic point of view : It was found that at 40°C, 1CGD bound to acrylic acid had a smaller inter atomic distance (Dis), larger Radial Distribution Function (RDF) and more hydrogen bonds than polyurethane, resulting in greater intermolecular forces, smaller molecular gaps and less moisture permeability. Note de contenu : - EXPERIMENTAL INSTRUMENTS AND MATERIALS - MOLECULAR DYNAMICS SIMULATION : Design of simulation experiment - Relevant parameters and their calculation - RESULTS AND DISCUSSION : Change in moisture permeability over time for two coatings of thin sheep leather - Analysis of Dis - Analysis of RDF - Analysis of hydrogen bonds En ligne : https://drive.google.com/file/d/1HqbAR3rIVaDhUh-S3imkp_p7vCkHcZBi/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38196 [article]

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Phytochemical screening and determination of tannin content of compounds from acacia xanthophloea as viable tanning agents for the leather industry / Michael Cheloti in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 5 (09-10/2022)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 106, N° 5 (09-10/2022) . - p. 218-233 Titre : Phytochemical screening and determination of tannin content of compounds from acacia xanthophloea as viable tanning agents for the leather industry Type de document : texte imprimé Auteurs : Michael Cheloti, Auteur ; Wangila Phanice, Auteur ; Kiprop Ambrose, Auteur ; Arthur Onyuka, Auteur ; Derese Solomon, Auteur ; Wekesa Ingrid, Auteur ; Sasia Alvin, Auteur ; Mukavi Justus, Auteur Année de publication : 2022 Article en page(s) : p. 218-233 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Acacia et constituants Agents de tannage Caractérisation Chimie végétale Criblage Phénols Tanins végétaux Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Acacia xanthophloea species, a tropical plant and a member of the Fabacea family is a ubiquitous and native shrub of the Eastern and Southern Africa regions. Although plant species in the Fabacea family are known as a source of tannins, very little is known about their phytochemistry. This study aimed at determining the suitability of Acacia xanthophloea as a viable tanning agent for the leather industry. The crude extract of Acacia xanthophloea was phytochemically screened using a series of qualitative tests while the total phenolic content and tannin content of the Acacia crude extract was determined spectrophotometrically using the Folin-Ciocalteu method. The functional groups of the compounds in the crude extract were determined using FTIR while Scanning Electronic Microscopy (SEM) was used to determine the surface morphological changes that take place during the tanning process. Results of phytochemical screening indicated the presence of: alkaloids, glycosides, flavonoids, phenolic compounds and saponins. Total phenolic content at 249.1mg TAE/g and total tannin content at 39.8mg TAE/g (16%) is reported. The results of this study indicate that the organic extract of Acacia xanthopholea could be a good source of tannins for leather tanning. Note de contenu : - METHODS : Sample collection - Sample preparation and extraction - Phytochemical screening - Total phenolic content - Tannin content - Fourier transform infrared spectroscopy (FTIR) characterisation - SEM analysis - RESULTS AND DISCUSSION : Phytochemical screening - Tannin content (TPC) - FTIR characterisation of the crude extract - Scanning electronic microscope (SEM) analysis - Table 1 : Summary of the test for the phytochemicals, observations and the results - Table 2 : Total phenolic content, total non-tannin content and total tannin content - Table 3 : Shows attributes of FTIR spectra acquired for bark crude extract of Acacia xanthophloea En ligne : https://drive.google.com/file/d/14IkrqSFxaH65b7xkokAtUw1zSBuEyZhf/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38197 [article]

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Blueprint for leather technology / Richard Daniels in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 5 (09-10/2022)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 106, N° 5 (09-10/2022) . - p. 224-227 Titre : Blueprint for leather technology Type de document : texte imprimé Auteurs : Richard Daniels, Auteur Année de publication : 2022 Article en page(s) : p. 224-227 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chimie Cuirs et peaux Cuirs et peaux -- Effets de la température Matériaux Physique Procédés de fabrication Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : This work can be considered as a blueprint, a flexible roadmap, for leather technologists. It is different from the familiar linear view of leather making as It does not follow step-by-step events as usually described in quality control manuals or defined by formulations and instructions. It's a holistic perspective on manufacture. Note de contenu : - BLUEPRINT FOR A TECHNOLOGY : (a) Material properties - (b) Applied physics - (c) Applied chemistry - APPLICATIONS - Panel 1 : Blueprint for a technology - Panel 1a : Blueprint : material properties - Panel 1b : Blueprint : applied physics - Panel 1c : Blueprint : applied chemistry - Example 1a et 1b : Effects of temperature within leather manufacture En ligne : https://drive.google.com/file/d/1ZY8boLMPA9fUipQlIUKjIEmfg3gIT9o0/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38198 [article]

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