Synthesis of orthanilic acid modified glyoxylated melamine resin with improved retanning and thermal properties / Muhammad Naveed Ashraf in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 103, N° 3 (05-06/2019)

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 103, N° 3 (05-06/2019) . - p. 142-149 Titre : Synthesis of orthanilic acid modified glyoxylated melamine resin with improved retanning and thermal properties Type de document : texte imprimé Auteurs : Muhammad Naveed Ashraf, Auteur ; Shahzad Mehmood Khan, Auteur ; Shahid Munir, Auteur ; Rashid Saleem, Auteur Année de publication : 2019 Article en page(s) : p. 142-149 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Agents de tannage Cuirs et peaux -- Analyse Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés organoleptiques Mélamine glyoxal Polymères -- Synthèse Retannage Rhéologie Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Amino resins have found important uses in leather manufacturing due to their selective filling properties. Conventional amino resins are produced from formaldehyde and result in an increase of formaldehyde content in finished leather greater than the permitted limits. Due to strict legislations and restrictions regarding formaldehyde contents in leather goods there is a growing demand to produce formaldehyde-free leather. In this study formaldehyde-free resins with improved thermal stabilities were prepared using glyoxal as condensing agent and orthanilic acid (o-amino-benzene sulphonic acid) as a sulfonating agent. The glyoxal to melamine ratio (G/M) was varied from 2-6 and orthanilic acid to melamine ratio (ONA/M) was varied from 0.5-3 to produce aqueous solutions of the melamine resins. The viscosity trend in the series of resins was observed by varying the degree of sulfonation and varying the glyoxal/melamine ratio. Progress of reaction was monitored by FTIR spectrum through functional group region. Newly synthesised melamine resins (MGONA) were comparatively applied on leather as a retanning agent against a conventional melamine-formaldehyde resin and further evaluated for tear strength, tensile strength and elongation at break. The leather retanned with the optimal resin was further assessed for organoleptic properties and SEM analysis. The thermal stability of the optimised resin was also evaluated comparatively against a conventional resin. The optimised polymeric resin was free from formaldehyde plus having better retanning properties and improved thermal stability. Note de contenu : - EXPERIMENTAL PROCEDURE : Chemicals and apparatus - Synthesis of glyoxylated melamine resins using orthanilc acid as sulfonating agent - RESULTS AND DISCUSSION : Schematic route - Rheology of resins - Application of MGONA resins as retanning agent - Quantitative free formaldehyde contents in leather - Mechanical characteristics of retanned leather - Organoleptic properties - SEM analysis (JEOL 6490) - Thermogravimetric analysis - Structural elucidation - Table 1 : Mole ratio and physical characteristics of synthesised MGONA resins - Table 2 : Leather processing conditions - Table 3 : Physical properties of leather after retanning process Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32671 [article]

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