Methanol degradation mechanisms and permeability phenomena in novolac epoxy and polyurethane coatings / Ting Wang in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 18, N° 3 (05/2021)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 18, N° 3 (05/2021) . - p. 831-842 Titre : Methanol degradation mechanisms and permeability phenomena in novolac epoxy and polyurethane coatings Type de document : texte imprimé Auteurs : Ting Wang, Auteur ; Shicong Luo, Auteur ; Chenyu Wang, Auteur ; Jing Wang, Auteur ; Claus Erik Weinell, Auteur ; Kim Dam-Johansen, Auteur ; Juan José Segura, Auteur ; Erik Graversen, Auteur ; Søren Kiil, Auteur Année de publication : 2021 Article en page(s) : p. 831-842 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Absorption Adsorption Epoxy novolac Liaisons hydrogène Méthanol Perméabilité Polyuréthanes Revêtements organiques Index. décimale : 667.9 Revêtements et enduits Résumé : On a global scale, methanol is one of the most important feedstocks and is used widely as solvent and co-solvent. However, due to the polar nature and associated ability to conduct current, the small molecule can take part in galvanic corrosion of metal storage tanks and degrade the barrier properties of protective coatings. In the present work, we investigated the degradation of two novolac epoxy coatings and a polyurethane (PU) coating exposed to methanol with the aim of quantifying the various degradation paths. Absorption and desorption rates were measured and the thermomechanical properties followed by dynamic mechanical analysis. For evaluation of the coating barrier properties (i.e., breakthrough time and steady state permeation rates of methanol), permeation cells were applied. During methanol absorption, simultaneous leaching of certain coating ingredients and bonding of methanol to the binder matrix via hydrogen bonds was evidenced. In terms of classification, the bonding of methanol took place by two types of mechanisms. In Type I, the methanol molecule forms a single hydrogen bond to the coating network, thereby acting as a plasticizer, which decreases the coating storage modulus and glass transition temperature. For Type II bonding of methanol, on the other hand, two hydrogen bonds to the coating network form per molecule, resulting in so-called physical crosslinking. The Type I mechanism boosted segmental mobility and contributed to the leaching of the plasticizer benzyl alcohol from the novolac epoxy coatings and residual solvents (i.e., naphtha and xylene) from the PU coating. Following the methanol desorption, and attributed to an increased effective crosslinking density from Type II bound methanol, the novolac epoxy and PU coatings exhibited significant increases in the glass transition temperatures. In addition, for the three coatings, a gradual decline in the permeability rate of methanol was observed over time. These enhanced (and unexpected) barrier properties result from a combination of effects ascribed to Type II bound methanol and the leaching process. Note de contenu : - Experimental methods for coating degradation studies and aims of the work - EXPERIMENTAL : Materials - Absorption and desorption experiments - Permeation rate experiments - Dynamic mechanical analysis - Gas chromatography-mass spectrometry - RESULTS AND DISCUSSION : Methanol absorption and desorption - Methanol permeation rate - Permeability measurement across thermoplastic films - Permeability measurement across methanol-exposed coating - Water and ethanol absorption and desorption - Table 1 : Main components of the experimental coatings. Additional details can be found in an earlier work on acid degradation of organic coatings. NE-CA = Novolac Epoxy-Cycloaliphatic Amine. NE-PA = Novolac Epoxy-Polyamide - Table 2 : Coating properties and weight changes after immersion for 168 h (Mi) and unrestricted evaporation for 168 h (Ml) of the NE-CA, NE-PA, and PU films - Table 3 : Weight loss (relative to the original nonexposed film), Ml, and the glass transition temperature of the NE-CA, NE-PA, and PU coatings (168 h methanol immersion) - Table 4 : Breakthrough velocity (Rb) and permeation rate (Rperm) of methanol across NE-CA, NE-PA, and PU films - Table 5 : Weight changes of NE-CA films after immersion for 168 h (Mi) followed by unrestricted evaporation for 168 h (Ml) - Scheme : Chemical structures of epoxy phenol novolac resin, copolymer of benzenamine and formaldehyde (one constituent of polyamide), 4,4′-methylenebis(cyclohexylamine) and 1,6-hexamethylene diisocyanate DOI : https://doi.org/10.1007/s11998-020-00446-w En ligne : https://link.springer.com/content/pdf/10.1007/s11998-020-00446-w.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35933 [article]

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Preparation and characterization of immobilized Panus conchatus bio-balls for fur dye wastewater / Ding Shaolan in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 100, N° 5 (09-10/2016)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 100, N° 5 (09-10/2016) . - p. 241-245 Titre : Preparation and characterization of immobilized Panus conchatus bio-balls for fur dye wastewater Type de document : texte imprimé Auteurs : Ding Shaolan, Auteur ; Xie Linhua, Auteur ; Dong Lingxiao, Auteur ; Jing Wang, Auteur Année de publication : 2016 Article en page(s) : p. 241-245 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Alginate de calcium L'alginate de calcium ou polymannuronate calcique, de formule (C6H7Ca1/2O6)n, est un additif alimentaire (E404) utilisé dans les boissons, constitué d'alginate et de calcium. Il s'agit d'une longue molécule synthétisée à partir de l'acide alginique, extrait d'algues brunes, constitué d'unités glucidiques formant une chaîne. Bains de teinture Bains de teinture -- Epuration Champignons et constituants Eaux usées -- Epuration Eaux usées -- Teneur en colorants Fourrures -- Teinture Glutaraldéhyde Laccases Les laccases (EC 1.10.3.2) appartiennent à une famille d'enzymes ayant pour cofacteur du cuivre. C'est une oxydase (oxydoréductase, EC 1) que l'on retrouve dans de nombreuses plantes, champignons et micro-organismes. Le cuivre est lié sur plusieurs sites de la protéine. On distingue trois types. Les types 2 et 3 sont appelés grappe tri-nucléaire. Le cuivre du type 1 est soluble dans l'eau. Le mercure déplace le cobalt complexé dans les laccases. Les complexants du cuivre peuvent le déplacer et le remplacer par du cobalt. Les cyanures complexent également le cuivre, mais dans ce cas il n'est pas possible de réinsérer du cobalt. Les laccases oxydent les dérivés phénoliques mais d'une façon ménagée qui transforme la lignine en monolignol. Polyacétate de vinyle Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Using four carriers, Panus conchatus with the highly effective decoloration producing laccase was immobilized by the embedding method. By comparing their balling performance and the mechanical strength, the optimal immobilized carrier was determined. The feasibility of the immobilized Panus conchatus for decoloration of fur dye industrial wastewater was studied. The results show that the immobilized bio-balls have the higher dye decoloring speed and rate than those of the free Panus conchatus. The immobilized prepared by PVA complex embedding method have the better comprehensive performances so as to shorten the decoloring time and increase the decoloring rate. The decoloring rates of the immobilized bio-balls to the acid dyes and the disperse dyes are 98.09% and 91.47% respectively. Note de contenu : - EXPERIMENTAL PROCEDURES : Apparatus and materials - Preparation of culture medium, and the activity and the culture of the thalli - Preparation of the immobilized Panus conchatus bio-balls - RESULTS AND DISCUSSION : Comparison of the performances of the bio-balls prepared by the different immobilized carriers - Experimental results and discussion of the decoloring performance of CA-glutaraldehyde bio-balls on the fur dyes - Experimental results and discussion of the decoloring performance of PVA-CA bio-balls on the fur dyes - Experimental results and discussion of the decoloring performance of PVC complex bio-balls on the fur dyes - Experimental results and discussion of the decoloring performance of SA-CA-PAC bio-balls on the fur dyes - Experimental results and discussion of the decoloring performance of free Panus conchatus on the fur dyes En ligne : https://drive.google.com/file/d/1iBVHUqrzYjS5NIm3CDLr7HWnylmrwQUl/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=27088 [article]

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Reconnection of cysteine in reduced hair with alkylene dimaleates via thiol-Michael click chemistry / Yuwen Wu in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 46, N° 3 (06/2024)  

[article]  inINTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 46, N° 3 (06/2024) . - p. 457-467 Titre : Reconnection of cysteine in reduced hair with alkylene dimaleates via thiol-Michael click chemistry Type de document : texte imprimé Auteurs : Yuwen Wu, Auteur ; Ling Ma, Auteur ; Timson Chen, Auteur ; Kuan Chang, Auteur ; Jing Wang, Auteur Année de publication : 2024 Article en page(s) : p. 457-467 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cheveux -- Propriétés mécaniques Cheveux -- Soins et hygiène Chimie click Cosmétiques Dimaléate d'alkylène Fibres kératiniques Liaisons disulfures Thiols Index. décimale : 668.5 Parfums et cosmétiques Résumé : - OBJECTIVES : Conventional hair permanent waving (PW) and permanent straightening processes typically involve two steps: reduction, for breaking -S-S- bond in cystine into cysteine and oxidation for -S-S- bond reconnection. However, it is known that the hair incurs damage during the oxidation step. In this work, we proposed a novel strategy to reconnect reduced disulfide bonds in hair via the thiol-Michael click reaction, by using a symmetric Michael reagent. - METHODS : Virgin black Chinese hair was reduced using 8% wt thioglycolic acid and employed as model hair containing a high content of broken disulfide bonds. The reduced hair was treated with 1,4-n-butylene dimaleate. Raman spectroscopy and Fourier transform infrared spectroscopy (FT-IR) were used to verify the chemical changes occurred in untreated and treated hair fibre. Single-fibre mechanical properties and thermal properties of the hair were evaluated using tensile testing and differential scanning calorimetry (DSC), respectively. - RESULTS : The 1,4-n-butylene dimaleate could reconnect free thiol groups generated by disulfide bond reduction via thiol-Michael click reaction and significantly improve the mechanical strength of hair compared to that of the reduced hair. Secondary conformational resolution analysis of FT-IR results revealed that the content of α-helix structure could be restored after treatment with 1,4-n-butylene dimaleate. The intermolecular forces established by the newly generated C-S bonds compensate the broken disulfide bonds and enhance the fracture strength of the hair compared to that of reduced hair. Michael reagents of similar structure also showed similar performance in restoring the mechanical properties of reduced hair. - CONCLUSIONS : Our data suggest that 1,4-n-butylene dimaleate can restore the mechanical properties of reduced hair by reconnecting reduced disulfide bonds and restoring the secondary conformation of hair keratin. Note de contenu : - MATERIALS AND METHODS : Reagents - Synthesis of 1,4-n-butylene dimaleate - Hair samples - Hair tensile property tests - Fluorescence microscopy characterization of free thiol groups - Characterization of hair - RESULTS AND DISCUSSION : Click reaction of free thiol groups in hair - Restoration of mechanical properties of reduced hair - Effect of different treatments on the thermal properties of hair - Evidence of the ability of 1,4-n-butylene dimaleate to restore the disrupted secondary conformation of reduced hair keratin - Restorative performance of alkylene dimaletates with different carbon chain lengths to that of 1,4-n-butylene dimaleate DOI : https://doi.org/10.1111/ics.12944 En ligne : https://drive.google.com/file/d/1zZm-Vh22Gbs3x-QX1AuXSjUWukCVcve6/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=41346 [article]

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Sodium hyaluronates applied in the face affects the diversity of skin microbiota in healthy people / Chen He in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 45, N° 3 (06/2023)  

[article]  inINTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 45, N° 3 (06/2023) . - p. 373-386 Titre : Sodium hyaluronates applied in the face affects the diversity of skin microbiota in healthy people Type de document : document électronique Auteurs : Chen He, Auteur ; YingXue Yue, Auteur ; Ruilong Li, Auteur ; Yiping Huang, Auteur ; Luan Shu, Auteur ; Huixia Lv, Auteur ; Jing Wang, Auteur ; Zhenhai Zhang, Auteur Année de publication : 2023 Article en page(s) : p. 373-386 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Hyaluronane Microbiote cutané Peau -- Soins et hygiène Séquençage des acides nucléiques Visage -- Soins et hygiène Index. décimale : 668.5 Parfums et cosmétiques Résumé : - Objective : A healthy and stable microbiome has many beneficial effects on the host, while an unbalanced or disordered microbiome can lead to various skin diseases. Hyaluronic acid is widely used in the cosmetics and pharmaceutical industries; however, specific reports on its effect on the skin microflora of healthy people have not been published. This study aimed to determine the effect of sodium hyaluronate on the facial microflora of healthy individuals. - Methods : Face of 20 healthy female volunteers between 18 and 24 years was smeared with sodium hyaluronate solution once per day. Cotton swabs were used to retrieve samples on days 0, 14, and 28, and high-throughput sequencing of 16 S rRNA was used to determine the changes in bacterial community composition. - Results : Facial application of HA can reduce the abundance of pathogenic bacteria, such as Cutibacterium and S. aureus, and increase the colonization of beneficial bacteria. - Conclusion : This is the first intuitive report to demonstrate the effect of hyaluronic acid on facial microflora in healthy people. Accordingly, sodium hyaluronate was found to have a positive effect on facial skin health. Note de contenu : - MATERIALS AND METHODS : Materials and reagents - Participants - Sample collection and preservation - 16 S rRNA sequencing - Statistical analysis - Alpha-diversity of skin microbiota and dilution curve - B-Diversity analysis - RESULTS AND DISCUSSION : Alpha-diversity of skin microbiota and dilution curve - Composition and abundance of skin microbiota - B-Diversity analysis - Table 1 : 1 Software & database information DOI : https://doi.org/10.1111/ics.12845 En ligne : https://drive.google.com/file/d/1iYJ5tqGBg-aBO7KTJDs8Dpo3vnvAETXZ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39568 [article]

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Studies of the fibre structure and dyeing properties of Calotropis gigantea, kapok and cotton fibres / Qin Chen in COLORATION TECHNOLOGY, Vol. 129, N° 6 (12/2013)  

[article]  inCOLORATION TECHNOLOGY > Vol. 129, N° 6 (12/2013) . - p. 448-453 Titre : Studies of the fibre structure and dyeing properties of Calotropis gigantea, kapok and cotton fibres Type de document : texte imprimé Auteurs : Qin Chen, Auteur ; Tao Zhao, Auteur ; Ming Wang, Auteur ; Jing Wang, Auteur Année de publication : 2013 Article en page(s) : p. 448-453 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Absorption Calotropis gigantea Coton Le coton est une fibre végétale qui entoure les graines des cotonniers "véritables"(Gossypium sp.), un arbuste de la famille des Malvacées. Cette fibre est généralement transformée en fil qui est tissé pour fabriquer des tissus. Le coton est la plus importante des fibres naturelles produites dans le monde. Depuis le XIXe siècle, il constitue, grâce aux progrès de l'industrialisation et de l'agronomie, la première fibre textile du monde (près de la moitié de la consommation mondiale de fibres textiles). Diffractométrie de rayons X Fibres végétales -- Analyse Fibres végétales -- Propriétés mécaniques Fibres végétales -- Propriétés tinctoriales Fourier, Spectroscopie infrarouge à transformée de Kapok Le kapok, en malais kapuk, est une fibre végétale que l'on tire de fruits de plusieurs arbres de la famille des Bombacaceae. On utilise plus particulièrement ceux de Ceiba pentandra, le kapokier (aussi appelé « fromager »), un grand arbre des zones tropicales, originaire de Java. Ceux de Bombax ceiba, un autre fromager, peuvent également être employés. Cette fibre très légère a pour caractéristique son imperméabilité et son imputrescibilité. Elle est constituée par les poils fins et soyeux recouvrant les graines. Microscopie électronique à balayage Morphologie (matériaux) Surfaces -- Analyse Index. décimale : 667.3 Teinture et impression des tissus Résumé : Calotropis gigantea, kapok and cotton fibres are all natural cellulose fibres, but the first of these is rarely used in textile fabrics. In this study, the structure and chemical composition of these three kinds of fibre were studied, and the dyeing properties of fabrics made from each of them were compared. The purpose of this was to provide a theory basis for the application of C. gigantea fibre in the textile industry. The surface morphology and cross-section of C. gigantea fibre in comparison with kapok and cotton were studied by scanning electron microscopy. Their fibrous structures were analysed by Fourier Transform-infrared spectroscopy and X-ray diffraction. The mechanical properties and water absorption capabilities were also measured and compared. Both C. gigantea fibre and kapok fibre exhibit a high degree of hollowness (80–90%), and no natural twist exists; there is a certain amount of lignin and hemicellulose in C. gigantea fibres; the crystallinity of C. gigantea fibres is 42.54%, and its crystallinity orientation index is 85.40%. C. gigantea fibre has the lowest tenacity but has the highest water content of the three kinds of fibre. The results of dyeing tests show that C. gigantea fabric has the lowest dye uptake and dye fixation. Note de contenu : - EXPERIMENTAL : Materials - Scanning electron microscopy - Elemental analysis - Analysis of the chemical components - Fourier Transform-infrared spectroscopy - X-ray diffraction analysis - Mechanical properties and water absorption capabilities - Dyeing - Dye uptake and fastness - RESULTS AND DISCUSSION : Scanning electron microscopy - Chemical composition analysis - Fourier Transform-infrared spectroscopy - X-ray diffraction analysis - Mechanical properties and water absorption capabilities - Dyeing properties of different fabrics DOI : 10.1111/cote.12051 En ligne : http://onlinelibrary.wiley.com/doi/10.1111/cote.12051/pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=19751 [article]

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