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Ajouter le résultat dans votre panierApplication of nonionic gemini aliphatic polyurethane surfactant for improving the performance of vegetable tanned leather / Shuangquan Lai in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIV, N° 11 (11/2019)
Titre : Application of nonionic gemini aliphatic polyurethane surfactant for improving the performance of vegetable tanned leather Type de document : texte imprimé Auteurs : Shuangquan Lai, Auteur ; Yong Jin, Auteur ; Liangjie Shi, Auteur ; Shenghua Wang, Auteur ; Heng Yang, Auteur Année de publication : 2019 Article en page(s) : p. 403-412 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Acide polyacrylique
Agents de tannage
Collagène
Cuirs et peaux -- Analyse
Cuirs et peaux -- Propriétés mécaniques
Cuirs et peaux -- Propriétés organoleptiques
Morphologie (matériaux)
Photostabilité
Polymères -- Synthèse
Polymères aliphatiques
Retannage
Surfactants
Surfactants -- Synthèse
Tannage végétal
Température de retraitIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Vegetable tanned leathers with good embossing, air permeability, natural look and pleasing firm handle properties have applied in many goods with multiple uses. However, the performances of vegetable tanned leathers still need a further improvement. In this work, a kind of nonionic gemini aliphatic polyurethane surfactants (GPUs) with different hydrophobic chain lengths as a retanning agent combined with polyacrylic acid (PAA) for condensed tannin tanned leathers to improve their performances. The effects of the alone or combined use of the PAA and GPU, the hydrophobic chain length of GPU, and the offer percentage of retanning agent were studied by evaluating the organoleptic properties, shrinkage temperature, mechanical properties of the obtained leathers. The best performance was found in the leather retanned with PAA and 12-GPU-550 complex retanning agent, and the mechanical properties of leather could be improved when the total offer percentage was controlled at 4 wt%. Moreover, the collagen fibers morphologies and lightfastness properties of leathers retanned with different retanning agents were investigated. The results showed that the total color difference ΔE and the yellowness index Δb decreased significantly with the introduction of 12-GPU-550, and the leather retanned with PAA and 12-GPU-550 complex retanning agent showed the lowest value of ΔE, demonstrating that the lightfastness properties were improved significantly. Therefore, it was an attractive way to combine use of PAA and 12-GPU-550 as complex retanning agent, which can improve the mechanical and lightfastness properties of vegetable tanned leathers simultaneously. Note de contenu : - MATERIALS AND METHODS : Materials - Synthesis of polyacrylic acid (PAA) - Synthesis of nonionic gemini aliphatic polyurethane surfactants (GPUs) - Application of the synthesized retanning agents - The organoleptic and physical mechanical properties of leathers - Scanning Electron Microscopy analysis of leathers - Light fastness properties of leathers
- RESULTS AND DISCUSSION : Effects of different retanning agents on the properties of leathers - Effect of the hydrophobic chain length of GPU on the properties of leathers - Effect of the offer percentage of complex retanning agent on the properties of leathers - SEM analysis of leathers - Effects of retanning agents on the lightfastness properties of leathersEn ligne : https://drive.google.com/file/d/1ajQdsq8W9LW8sFu6kytH1lIoq_J-RMzI/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33252
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIV, N° 11 (11/2019) . - p. 403-412[article]Réservation
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Titre : Effect of prepolymerization of acrylic acid under high gravity on the properties of acrylic resin retanning agent Type de document : texte imprimé Auteurs : Xin Shu, Auteur ; Weixing Xu, Auteur ; Bi Shi, Auteur ; Zhou Jian, Auteur Année de publication : 2019 Article en page(s) : p. 413-420 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Absorption
Acide polyacrylique
Agents de tannage
Colorimétrie
Croûte (cuir)On entend par "cuir en croûte" des cuirs ayant subi les opérations jusqu'au tannage, à l'exclusion de toute opération de corroyage ou de finissage, mais qui, par opposition aux wet-blue ont été séchés.
Cuirs et peaux -- Propriétés mécaniques
Poids moléculaires
Point isoélectriqueEn biochimie, le point isoélectrique (pI) ou potentiel hydrogène isoélectrique (pHI) est le pH auquel une molécule est sous forme d'ion mixte ou, en physico-chimie, le pH d'une solution aqueuse dans laquelle un solide existe sous un potentiel électrique neutre.
En physico-chimie : Selon Bolger, le caractère acide ou basique d'une surface s'exprime par son point isoélectrique " Is ou IEPS (Iso Electric point for the surface) " ou point de charge nulle " PCN ou PZC (Point of Zero Charge) ", défini comme étant le pH de la solution aqueuse dans laquelle le solide existe sous un potentiel électrique neutre. Si le pH de la solution est basique, la surface est acide, et inversement. La différence entre le PZC et l'IEPS est basée sur le phénomène d'adsorption spécifique. On peut considérer que si la grandeur mesurée ne dépend pas de la solution utilisée pour la mesurer (pH, concentration, nature des ions), alors on a affaire à un PZC. Dans le cas contraire, c'est un IEPS que l'on mesure. Par exemple, quand la mesure de goutte sessile à deux liquides est utilisée, on considère en général qu'il n'y a pas adsorption des ions de cette goutte et que la goutte déplace complètement l'alcane qui sert de deuxième liquide: on est alors en présence d’un PZC. Au contraire, dans les mesures de potentiel d'écoulement (streaming potential), la solution joue un rôle important et c'est un IEPS que l'on mesure. Enfin, la charge nette se définit grâce au pH de la solution aqueuse dans laquelle la surface métallique existe, dans un état électriquement neutre (c’est-à-dire [M-OH2+ surf]=[M-O- surf]) et au PZC.
- Si pH < PZC alors la charge nette est positive
- Si pH > PZC alors la charge nette est négative.
Il existe plusieurs méthodes expérimentales permettant de décrire l’état acido-basique de la surface : la mesure du potentiel d’écoulement, la photoélectrochimie, la mesure de l’angle de contact, et la spectroscopie XPS.
PrépolymérisationConsiste à faire atteindre, à un élément drapé d'une pièce, un état de début de polymérisation suffisant pour acquérir la stabilité géométrique et la pégosité permettant sa manipulation.
Cette opération a également pour but de faciliter la mise en œuvre du produit, par exemple :
• limiter le fluage ;
• limiter le taux de matières volatiles ;
• diminuer le collant d'un préimprégné ...
Cette opération peut également consister à amorcer une légère polymérisation préalable à un mélange, une résine ou un préimprégné afin de le rendre plus adapté à sa mise en œuvre ultérieure.
La prépolymérisation permet le stockage de sous-ensembles d'une pièce en attendant l'assemblage en monophase à l'occasion de la polymérisation de l'ensemble des éléments de la pièce.Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The effects of prepolymerization of acrylic acid (AA) in rotating packed bed (RPB) on the molecular weight and molecular weight distribution of polyacrylic acid (PAA) were investigated. Results showed that, compared with conventional polymerization in stirred tank reactor (STR), the prepolymerization in RPB followed by polymerization in STR produced PAA with lower weight-average molecular weight (Mw) and polydispersity index (PDI). The Mw of PAA decreased with increasing rotational speed of RPB from 800 rpm to 1400 rpm. Therefore, the use of RPB might be an effective strategy to control the molecular weight and molecular weight distribution of PAA. For exploring the value of this technology in preparing PAA retanning agent, PAAs were synthesized by using STR (STR-PAA, Mw=476,615 Dal, PDI=3.36) and RPB (RPB-PAA, Mw=193,386-288,321 Dal, PDI=1.55-1.86), and their performances in retanning were evaluated. Results showed that RPB-PAAs with low Mw had high absorptivity in wet blue and achieved a good filling property for leather because they could permeate into numerous microstructures of collagen fiber network. As for RPB-PAAs, high PDI led to a satisfactory selective filling property. The fullness, mechanical property, isoelectric point, and dyeability of leather were also affected by PAAs with different Mw and PDI. This work demonstrated the considerable influences of the molecular weight and molecular weight distribution of PAA on retanning property. A method to control these parameters was also presented. Note de contenu : - EXPERIMENTAL : Materials and equipment - Preparation of PAA - Preparation of PAA retanned crust leather - Determination of molecular weight - Absorption of PAA in leather - Thickening extend of leather and selective filling property of PAA - Mechanical properties - Isoelectric point determination - Color measurements
- RESULTS AND DISCUSSION : Effect of preparation method on the molecular weight and molecular weight distribution of PAA - Retanning properties of PAAsEn ligne : https://drive.google.com/file/d/1pCUBd25dnCUd4zcj5Yzh-uPPI7ZVeYND/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33253
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIV, N° 11 (11/2019) . - p. 413-420[article]Réservation
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Titre : Deep treatment of ammonia nitrogen tannery wastewater by an electro-Fenton system Type de document : texte imprimé Auteurs : Chen Hui, Auteur ; Li-Wei Chen, Auteur ; Li Shu Qing, Auteur ; Yao Hu, Auteur ; Shan Zhi-Hua, Auteur ; Dai Rui, Auteur ; Jie Yi, Auteur Année de publication : 2019 Article en page(s) : p. 421-428 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Azote ammoniacal
Eau -- Épuration -- Élimination des composés organiques
Eaux usées -- Epuration
Eaux usées -- Teneur en azote ammoniacal
Énergie -- Consommation
Fenton, Réaction de
Tannage -- DéchetsIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The effect of an Electro-Fenton system on the deep treatment of ammonia nitrogen (NH3-N) and corresponding removal rate was investigated in this article. By using simulated ammonia nitrogen wastewater, it included a Cl- concentration of 3000 mg/L, SO42- concentration of 100 mg/L according to conventional leather wastewater conditions. Furthermore, Cl- and SO42- can be used as supporting electrolyte. After pretreatment, the ammonia nitrogen concentration kept about 100 mg/L. The optimal treatment conditions of Electro-Fenton system were obtained throughout single factors experiments. The current density was 150 A/m2, the reaction time was 30 min, the plate spacing distance was 40 mm, and the reaction temperature was adjusted to 40°C. After flocculation treatment of leather wastewater, the ammonia nitrogen concentration was 142.11 mg/L, and the tanning wastewater was further treated with an Electro-Fenton system. The final ammonia nitrogen concentration was 11.23 mg/L, which meets the first-level wastewater discharge standard. The removal rate was 92.10%, which indicated that the Electro-Fenton system is one kind of clean, feasible and sustainable treatment method for the deep treatment of ammonia nitrogen in tannery wastewater. Note de contenu : - EXPERIMENTAL : Materials - Treatment of simulated ammonia nitrogen wastewater by electro-Fenton - Tanning wastewater treatment - Measurement of ammonia nitrogen concentration - COD cr measurement of tanning wastewater - Energy consumption during of electro-Fenton treatment
- RESULTS AND DISCUSSION : Treatment of simulated ammonia nitrogen wastewater by electro-Fenton - Ammonia nitrogen removal from tannery wastewater by electro-Fenton - Energy consumption by the electro-Fenton systemEn ligne : https://drive.google.com/file/d/1Hsz8qjc34jlp6868Xbet1lVoQWfrmfYX/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33254
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Titre : High-efficiency bio-degreasing technology for leather making - Characterization of catalytic hydrolysis properties of lipases towards fats based on greasy skin powder substrate Type de document : texte imprimé Auteurs : Yongkang Luo, Auteur ; Shan Li, Auteur ; Shencai Pan, Auteur ; Chunxian Zhang, Auteur ; Cai Huang, Auteur ; Biyu Peng, Auteur Année de publication : 2019 Article en page(s) : p. 429-439 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Catalyse
Cuirs et peaux -- Dégraissage
Cuirs et peaux de porcs
Hydrolyse
LipasesLes lipases sont des enzymes hydrosolubles capables d'effectuer l'hydrolyse de fonctions esters et sont spécialisées dans la transformation de triglycéride en glycérol et en acides gras (lipolyse). À ce titre, elles constituent une sous-classe des estérases.
Poudre de peauxIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Bio-degreasing technology based on the use of lipases has attracted more attention in the leather industry. Although lipases have been applied in leather making in the past, the previously reported lipase degreasing ratio is still not very high, i.e. less than 60%. In order to correctly understand the mechanism of lipase degreasing and to choose lipases and optimize the degreasing process for achieving efficient degreasing, a novel method of evaluating the catalytic hydrolysis properties of lipases towards skin fats based on a greasy skin powder substrate in an aqueous medium was established. This simulated the actual leather degreasing process and detected the amount of fatty acids produced. The special substrate was prepared; the determination conditions were optimized; then the performances of several typical lipases were evaluated. The results revealed that the lipase performances determined by the novel method were quite different from the standard method using emulsified olive oil substrate. There was a strong product-inhibition characteristic in the catalytic hydrolysis reaction of lipase, and the inhibition concentration of fatty acids varied with the lipase type, thus the maximum hydrolysis ratio of fats was only 67%. The lipases exhibited “super-activity” at pH around 9.5. This occurred because the fatty acids produced transformed into soluble soaps, thus the product-inhibition was weakened. According to the above results, a two-step lipase processing was made, i.e., beginning at pH 7.5 then 9.5. The hydrolysis ratio of fats rose to 82.57% from 46.23%, and the degreasing ratio increased from 50.78% to 89.68%. The new method with better repeatability can be used as a tool to correctly select lipases and optimize process parameters for lipase degreasing. Note de contenu : - EXPERIMENTAL : Materials - Preparation of the pigskin powder substrate rich in grease - Determination of lipase activity based on the prepared greasy skin powder substrate - Optimization of the method to terminate enzyme reaction - Water washing method - Hot drying method - Ethanol termination method - Acidification method - Acidification and water washing method - Absorption of fatty acids by pigskin powder after acidification - Extraction ratio of absorbed fatty acids by dichloromethane - Determination of lipase activity with the standard method - Evaluation of catalytic hydrolysis properties of some lipases towards fats in greasy skin powder - High-efficiency catalytic hydrolysis of fats by lipase and degreasing effect
- RESULTS AND DISCUSSION : Main parameters of the prepared greasy pigskin powder substrate - Optimization of the method to terminate lipase reaction - Impact of acidification on the absorption of fatty acids by pigskin powder - Extraction ratio of fatty acid by dichloromethane - Comparison of the measuring result of lipase activity between the novel and standard methods - Impact of lipase concentration on lipolytic activities of lipases - Impact of reaction time on lipolytic activity of lipases - Effect of temperature on lipolytic hydrolysis of lipaseEn ligne : https://drive.google.com/file/d/1Db6VxRnqj3vXDlsp1w3HSE05ySOJRZs3/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33255
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