Comparative retanning performance of ecofriendly melamine resins produced using different condensing agents / Muhammad Naveed Ashraf in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 105, N° 3 (05-06/2021)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 105, N° 3 (05-06/2021) . - p. 140-152 Titre : Comparative retanning performance of ecofriendly melamine resins produced using different condensing agents Type de document : texte imprimé Auteurs : Muhammad Naveed Ashraf, Auteur ; Shahzad Maqsood Khan, Auteur ; Shahid Munir, Auteur ; Rashid Saleem, Auteur Année de publication : 2021 Article en page(s) : p. 140-152 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés organoleptiques Mélamine sulfonée 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. Produits de condensation (chimie) Retannage Tannage synthétique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Formaldehyde has been a famous raw material for production of amino resins used in leather processing however; the proven carcinogenic hazards of formaldehyde contravene regulations are restricting the sale of leather goods with regard to human contact. In this study sulfonated melamine based resins were produced by using condensing agents other than formaldehyde, for example furfural, glyoxal, methylglyoxal and glutaraldehyde. Synthesised formaldehyde-free melamine resins were studied for determination of their molecular weights, thermal stability by TGA and spectroscopic studies using FTIR. Synthesised resins were used in leather retanning for investigation of their mechanical and organoleptic properties in comparison with leather samples based on a commercial resin. The effects of melamine resins on the fibrous structure of collagen were examined by SEM. Leather pieces were analysed for estimation of free formaldehyde contents and the pollution load of the retanning wastes was also investigated. The prepared resins conferred improved mechanical and organoleptic characteristics to the resulting leather compared to the control but the results produced by MGLSNA and MGSNA resins were more prominent. Leather produced from each resin sample was formaldehyde free. SEM images of the leather revealed the presence of fine grains with improved fibrous collagen structure especially for MGLSNA and MGSNA. Pollution load reduction efficiency of newly developed resins was improved in comparison with control indicating their better uptake and fixation in collagen fibres. Overall, all four novel resins produced formaldehyde-free leather with improved retanning and thermal properties but the results produced by MGLSNA and MGSNA resins were better due to introduction of more reactive sites and aromatic sulfonation agents. Note de contenu : - EXPERIMENTAL PROCEDURE : Chemicals and apparatus - Synthesis of sulfonated melamine resins - RESULTS AND DISCUSSION : Synthesis of sulfonated melamine resins - Physical characteristics of sulfonated melamine resins - Molecular weight determination of sulfonated melamine resins - Comparative application of sulfonated melamine resins on leather - Mechanical properties of leather retanned with sulfonated melamine resins - Organoleptic properties of leather retanned with sulfonated melamine resins - Characterisation of retanned leather by SEM - Determination of free formaldehyde content in leather - Thermo gravimetric analysis of sulfonated melamine resins - FTIR analysis - Wastewater analysis of retanning bath - Table 1 : Mole ratio and physical characteristics of sulfonated melamine resin prepared with different condensing agents - Table 2 : Dependence of the flow time, relative viscosity, specific viscosity, δ = ηsp - inηr and δ/c2 at different concentrations of SMFr resin - Table 3 : Dependence of the concentration of novel resins of study on δ/c2 - Table 4 : Leather processing recipe, materials and conditions - Table 5 : Mechanical properties of leather retanned with sulfonated melamine resins - Table 6 : Comparative pollution load efficiency of sulfonated melamine resins En ligne : https://drive.google.com/file/d/1N5Wt_oi9uVzToJ_7z1L_jwRfqTgOlm5M/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35834 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
22745	-	Périodique	Bibliothèque principale	Documentaires	Disponible

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]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
23641	-	Périodique	Bibliothèque principale	Documentaires	Disponible

Preparation and application of metanilic acid modified ecological melamine resins for making formaldehyde-free leather / Muhammad Naveed Ashraf in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 3 (05-06/2022)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 106, N° 3 (05-06/2022) . - p. 126-136 Titre : Preparation and application of metanilic acid modified ecological melamine resins for making formaldehyde-free leather 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. 126-136 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés organoleptiques Formaldéhyde -- Suppression ou remplacement 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. Retannage Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The objective of this study is to develop a novel melamine based resin suitable for producing formaldehyde-free leather with improved retanning properties. A series of resins was prepared by condensation of melamine, glyoxal and metanilic acid at varied mole ratios of reactants. Prepared resins were evaluated for retanning performance in leather in comparison with a commercial melamine resin to select the optimal resin. The mechanical and organoleptic properties of the optimal resin were found to be better than those of the commercial melamine resin. Tensile strength, tear strength and elongation of leather were increased by 17.43 %, 10.41 % and 8.62 % in direction parai lel to backbone while the increase in these parameters was 15.17 %, 9.79 % and 6.0% respectively in direction perpendicular to the backbone at same dosages. 100% reduction of free formaldehyde content was apparent in retanned leather and in the effluent produced by novel melamine resin. Pollution load study of the effluent showed a reduction in chemical oxygen demand, total suspended solids and total dissolved solids by 9.21 %, 5.60 % and 6.97 % for the novel melamine resin reflecting its improved exhaustion. The fibre structure of the leather produced using the optimal melamine resin was arranged in a more orderly pattern as confirmed by scanning electron microscopy, thus showing its improved retanning capability. These results prove that the optimal melamine resin is an effective retanning agent suitable for producing formaldehyde-free leather with a reduction in effluent pollution load. This work also presents an alternative for formaldehyde for amino resins to address its carcinogenic effects. Note de contenu : - EXPERIMENTAL PROCEDURE : Chemicals and apparatus - Synthesis of metanilic acid modified melamine-glyoxal resins - RESULTS AND DISCUSSION : Schematic route - Leather application of resins as retanning agent - Mechanical characteristics of retanned leather - Effect of melamine resins on organoleptic properties - SEM analysis - Quantitative determination of ree formaldehyde contents in leather - Thermogravimetric analysis (TGA) - FTIR analysis - Effluent analysis - Table 1 : Mole ratio and physical characteristics of synthesised MGMNA resins - Table 2 : Leather processing recipe conditions - Table 3 : Mechanical characteristics of leather retanned with novel MGMNA resins and commercial resin - Table 4 : Comparative characteristics of effluent for leathers retanned with novel resin MGMNA#09 and commercial melamine resin En ligne : https://drive.google.com/file/d/1VlBcJdgglhf3cE0A5J6OugVIVuK_otgv/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37757 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
23467	-	Périodique	Bibliothèque principale	Documentaires	Disponible

Preparation of formaldehyde-free melamine resins using furfural as condensing agent and investigation of their retanning performance / Muhammad Naveed Ashraf in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 103, N° 5 (09-10/2019)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 103, N° 5 (09-10/2019) . - p. 272-278 Titre : Preparation of formaldehyde-free melamine resins using furfural as condensing agent and investigation of their retanning performance Type de document : texte imprimé Auteurs : Muhammad Naveed Ashraf, Auteur ; Shahzad Maqsood Khan, Auteur ; Shahid Munir, Auteur ; Rashid Saleem, Auteur Année de publication : 2019 Article en page(s) : p. 272-278 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuir -- Teneur en formaldéhyde Cuirs et peaux -- Analyse Cuirs et peaux -- Propriétés organoleptiques Furfural 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. Polymères -- Synthèse Produits de condensation (chimie) Retannage Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Sulfonated amino resins are an important class of polymers which are used as retanning agents in the leather industry. There is challenge for such resins to be synthesised without formaldehyde to satisfy the strict regulation in leather goods. In this work, formaldehyde-free melamine based retanning agents have been synthesised by acid catalysed process using furfural as condensing agent and sodium metabisulfite as the sulfonating agent. Sulfonated melamine furfural (SMFr) resins were synthesised using different molar ratio of melamine, sodium metabisulfite and furfural. Stable and water-soluble resins were produced without etherification. The sodium metabisulfite to melamine ratio (SMB/M) was changed from 0.5-2.0 and furfural to melamine mole ratio (Fr/M) was varied from 2-6. The viscosity behaviour of the produced resins wâs evaluated with the increasing trend of sulfonation and increasing mole ratio of furfural to melamine. Functional group analysis and conversion of reactants into product was elucidated by FTIR. Synthesised formaldehyde-free resins (SMFr) were comparatively evaluated as retanning agents on goatskin wet-blue against a commercially available sulfonated melamine formaldehyde (SMF) resin. The retanning performance of synthesised resins was studied and found better than that of the commercial SMF resin. Note de contenu : - EXPERIMENTAL PROCEDURE : Materials and equipment - Preparation of SMFr resin - RESULTS AND DISCUSSION : Synthesis of SMFr resin - Viscosity trend of resins - Resin application on leather as retanning agent - Quantitative determination of free formaldehyde content in leather - Organoleptic properties of retanned leather - SEM examination (JEOL 6490) - Structure elucidation/FTIR spectroscopy analysis of SMFr resin En ligne : https://drive.google.com/file/d/1tehL2heU-liowrx614fHL9jzpSdLCcXB/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33003 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
21222	-	Périodique	Bibliothèque principale	Documentaires	Disponible

Synthesis of aniline 2,5 disulfonic acid modified ecofriendly melamine resins and their performance evaluation as leather retanning agents / Muhammad Naveed Ashraf in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 104, N° 5 (09-10/2020)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 104, N° 5 (09-10/2020) . - p. 216-226 Titre : Synthesis of aniline 2,5 disulfonic acid modified ecofriendly melamine resins and their performance evaluation as leather retanning agents Type de document : texte imprimé Auteurs : Muhammad Naveed Ashraf, Auteur ; Shahzad Maqsood Khan, Auteur ; Shahid Munir, Auteur ; Nafisa Gull, Auteur ; Shahid Khan, Auteur ; Rashid Saleem, Auteur ; Rafi Ullah Khan, Auteur Année de publication : 2020 Article en page(s) : p. 216-226 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Agents de tannage Caractérisation Cuirs et peaux -- Propriétés mécaniques Cuirs et peaux -- Propriétés organoleptiques Eaux usées -- Analyse Formaldéhyde -- Suppression ou remplacement Mélamine -- Synthèse Microscopie électronique à balayage Poids moléculaires Retannage Rhéologie Stabilité thermique Thermogravimétrie Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Amino resins used in the leather retanning process are condensation products of formaldehyde which makes such resins objectionable due to environmental hazards. Due to the carcinogenic effects of formaldehyde, there is a growing demand to produce formaldehyde-free leather. This work involves the synthesis of formaldehyde free melamine resins for producing environment friendly leather with improved retanning properties and thermal stability. A series of resins was produced by condensation of glyoxal and melamine at varied mole ratios. Stability and water solubility was achieved by sulfonation with aniline 2,5 disulfonic acid at varied degrees of sulfonation. Resins were evaluated to measure the viscosity trends in series. Synthesised resins were studied for their comparative retanning properties in comparison with a commercial melamine resin as control. Mechanical properties like tensile strengths tear strengths, and elongation at break were measured and found to be improved. Similarly, the organoleptic properties were also evaluated and found to be better than for the control. Retanned pieces of leather were examined by SEM and tested for free formaldehyde content. The optimal resin was subjected to analysis by FTIR, TGA and molecular weight determination. Effluents collected from retanning baths were tested for pollution load efficiency. The results of the study confirmed that the prepared resins were supportive in producing formaldehyde-free leather with improved mechanical and organoleptic properties. The thermal stability of the resulting resins and pollution load efficiency was also found to be improved. Note de contenu : - EXPERIMENTAL PROCEDURE : Chemicals and apparatus - Preparation of aniline 2,5 disulfonic acid modified melamine glyoxal resins - RESULTS AND DISCUSSION : Schematic route - Rheology of resins - Leather application of MGADS resins as retanning agent - Mechanical properties of leather treated with MGADS resins - Organoleptic properties - SEM analysis of retanned pieces of leather - Quantitative estimation of free formaldehyde contents in leather - Thermogravimetric analysis - Structural elucidation - Molecular weight determination of optimal MGADS resin - Analysis of effluent En ligne : https://drive.google.com/file/d/1QEiBifPuL-H5we65DiaVyKq52J6mp4uk/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34522 [article]

Réservation

Réserver ce document

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
22289	-	Périodique	Bibliothèque principale	Documentaires	Disponible

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)  

Permalink

Synthesis of formaldehyde free amino resin to produce green eco-labelled leather with improved retanning properties / Muhammad Naveed Ashraf in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXV, N° 4 (04/2020)  

Permalink

---

1 (1 - 7 / 7)