Synthesis of eco-friendly polymeric resins and their rote in making leather with improved retanning properties and wastewater pollution / Muhammad Naveed Ashraf in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 104, N° 6 (11-12/2020)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 104, N° 6 (11-12/2020) . - p. 288-299 Titre : Synthesis of eco-friendly polymeric resins and their rote in making leather with improved retanning properties and wastewater pollution Type de document : texte imprimé Auteurs : Muhammad Naveed Ashraf, Auteur ; Shahzad Maqsood Khan, Auteur ; Shahid Munir, Auteur Année de publication : 2020 Article en page(s) : p. 288-299 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Biopolymères Biopolymères -- Synthèse Cuir -- Teneur en formaldéhyde Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés organoleptiques Eaux usées -- Analyse Fourier, Spectroscopie infrarouge à transformée de Glutaraldéhyde Mélamine La mélamine, de nom chimique 1,3,5-triazine-2,4,6-triamine, est parfois dénommée cyanuramide ou cyanurotriamine. Sa formule brute est C3H6N6. Les "résines mélamine-formaldéhyde" ou "mélamine-formol" (sigle MF) sont appelées "mélamine" dans le langage courant. Elles font partie de la famille des aminoplastes qui regroupe des résines thermodurcissables aminées, issues d'un comonomère tel l'urée ou la mélamine, parfois le thiocarbamide, le cyanamide hydrogène ou le dicyandiamide ; le second comonomère étant le formaldéhyde. Morphologie (matériaux) Poids moléculaires Polymères -- Synthèse Retannage Rhéologie Sulfanilique, Acide Thermogravimétrie Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : In this work a novel and eco-friendly retanning agent was developed to eliminate the potential risk of formaldehyde occurrence in leather along with improving the characteristics of leather. A series of sulfanilic acid modified melamine-glutaraldehyde resins were produced at varied mole ratios of melamine, glutaraldehyde and sulfanilic acid. The glutaraldehyde to melamine mole ratio (GL/M) was varied from 2 to 6 whereas the sulfanilic acid to melamine mole ratio (SNA/M) was varied from 0.5 to 3. The viscosity trend of resins in the series was studied. Synthesised resins were used in retanning leather in comparison with a melamine-formaldehyde resin as a control. Retanned pieces of leather were evaluated for their mechanical properties and organoleptic properties. Samples of leather retanned with the optimal resin were also analysed for comparative free formaldehyde determination. Scanning electron microscopy was performed to study the morphology of grain surface and fibre structure of resulting leather. Effluent received from retanning process was analysed for pollution load estimation. The optimum resin was subjected to determination of its molecular weight, to thermo gravimetric analysis and FTIR. It was obvious from the results of this study that the optimal resin produced a leather with improved mechanical and organoleptic properties in comparison with the control. Estimation of formaldehyde content in leather proved the complete elimination of free formaldehyde in leather whereas the level in control leather was 152mg/kg. Results from the pollution load study of waste water confirmed an improvement in efficiency of COD, TDS, TSS and formaldehyde by 13.40%, 9.71%, 8.82% and 100% respectively. SEM monographs of grain surface and collagen fibres showed better filling, distribution and reactivity of the optimal resin. Thermo gravimetric analysis proved the increase in thermal stability of developed resin by 16.3% as compared to control. The eco-friendly condensation polymer produced in this work was considered suitable for making formaldehyde-free leather with improved retanning properties, thermal stability and pollution load. Note de contenu : - EXPERIMENTAL PROCEDURE : Chemicals and apparatus - Preparation of sulfanilic acid modified melamine-glutaraldehyde resins (MGLSNA) - RESULTS AND DISCUSSION : Schematic route of synthesis - Viscosity trend in MGLSNA series - Leather application of MGLSNA resins - Mechanical properties of retanned leather - Organoleptic properties of leather - Comparative SEM analysis of leather - Quantitative estimation of fre formaldehyde content in leather - Molecular weight determination of optimal MGLSNA resin - Thermo gravimetric analysis - Structural elucidation through FTIR - Effluent analysis - Table 1 : Mole ratios and physical characteristics of prepared MGSLNA resins - Experimental data - Table 2 : Leather processing materials, conditions and recipe - Table 3 : Mechanical characteristics of leather retanned with resins MGLSNA - Table 4 : Dependence of flow time, relative viscosity, specific viscosity, Δ, ηsp - inηr and Δ/c2 different concentrations of MGLSNA resin #08 - Table 5 : Comparative pollution load reduction efficiency of optimum MGLSNA resin - Scheme 1 : Formation of hydroxy derivatives of melamine - Scheme 2 : Preparation of sodium salt of sulfanilic acid - Scheme 3 : Sulfonation of hydroxy derivatives of melamine - Scheme 4 : Condensation of monomers to produce resin MGLSNA - Fig. 1 : Comparative study of organoloeptic properties of MGLSNA resins - Fig. 2 : Scanning electron micrographs of cross section of grain surface (X50) and collagen fibre (X500) - Fig. 3 : Dependence of Δ/c2 on the concentration of optimal resin MGLSNA#08 - Fig. 4 : TGA of optimal resin MGLSNA#08 and commercial melamine resin - Fig. 5 : FTIR of MGLSNA#08 resins En ligne : https://drive.google.com/file/d/1ebHKU_sNQN0nAZXxMvUEazp3CWa7RHtj/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34910 [article]

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