Elaboration de revêtements hybrides par le procédé sol-gel pour conférer de nouvelles fonctions à des matériaux textiles

This work consists to provide a functionalization of textile surfaces by the sol-gel process using alcoxysilanes. The final aim is to impart water repellent, flame retardant and fluorescent features to textile surfaces. Firstly, the effects of synthesis parameters such as the concentration of the alcoxysilanes and the impregnation time of the fabrics in the solution (sol) prepared have been thoroughly investigated. Then, we have prepared a silica modified sol which is expected to induce a water repellent feature to textile. To investigate the water repellency under practical conditions, the common “rain test” was used according to AATCC test method 22-2005 also mechanical properties of treated un untreated textile was studied according to ISO 13934. Furthermore, thermal properties of sol-gel modified textiles were investigated and their water repellency abilities were assessed and compared after photo ageing upon UV irradiations.Secondly, we have showed that the immobilization of ionic liquids onto the surface of textile fabrics can be achieved by the sol-gel process, which is of a growing interest due to its simplicity and flexibility. For this aim, two ionic liquids were synthesized using halogenated alkoxysilane, and then grafted onto the cotton fabrics by sol- gel process .The functionalized cotton fabrics exhibit good water repellency and flame stability. Finally, a fluorophores bearing phenolic hydroxyl and pyridinium end groups have been synthesized and grafted into cellulosic fiber by sol -gel process. This fluorophores have been firstly synthesized by double Heck couplings, and then we have studied their photo physical behavior as function of their concentration both in ethanol and in the textile. We have also grafted the fluorophores in cellulosic textile by sol gel method to have fluorescent and PH-sensitive properties.Ce travail de recherche consiste à proposer une fonctionnalisation des surfaces textiles par le procédé sol-gel à partir d’alcoxysilanes. L‘objectif est de conférer aux textiles des propriétés hydrofuges, ignifuges et fluorescentes. La première partie de notre étude traite dans un premier temps les paramètres de synthèse des sols et leur application sur différentes étoffes textiles. Ensuite, nous nous sommes intéressés à la synthèse des sols avec des alcoxydes de silicium permettant d’avoir des propriétés hydrofuges. Par la suite, les propriétés d’adsorption et de non mouillabilité des textiles traités ont été déterminées selon le standard AATCC- 22 et celles mécaniques selon la norme ISO 13934. Nous avons également étudié la stabilité thermique par des analyses ATG et les propriétés de non mouillabilité de ces textiles en fonction de leur photovieillissement accéléré. Dans un deuxième temps et dans l’optique de développer des textiles ignifuges, nous avons montré que l’immobilisation des LIs à la surface des textiles peut être réalisée par le procédé sol-gel. Pour ce faire nous avons tout d’abord synthétisé des liquides ioniques à partir d’un alcoxyde de silicium halogéné. Le sel obtenu est ensuite greffé sur des matrices textiles par le procédé sol- gel.Enfin, la dernière partie de l’étude consiste en la synthèse de fluorophores organiques par un procédé utilisant le couplage de type Heck. Leurs propriétés de photoluminescence ont été étudiées. Nous avons ainsi pu les greffer sur des surfaces pour développer des traceurs textiles fluorescents et des sondes pH fluorescentes

Elaboration of hybrid coatings by sol-gel method for functionalization of textile materials

Ce travail de recherche consiste à proposer une fonctionnalisation des surfaces textiles par le procédé sol-gel à partir d’alcoxysilanes. L‘objectif est de conférer aux textiles des propriétés hydrofuges, ignifuges et fluorescentes. La première partie de notre étude traite dans un premier temps les paramètres de synthèse des sols et leur application sur différentes étoffes textiles. Ensuite, nous nous sommes intéressés à la synthèse des sols avec des alcoxydes de silicium permettant d’avoir des propriétés hydrofuges. Par la suite, les propriétés d’adsorption et de non mouillabilité des textiles traités ont été déterminées selon le standard AATCC- 22 et celles mécaniques selon la norme ISO 13934. Nous avons également étudié la stabilité thermique par des analyses ATG et les propriétés de non mouillabilité de ces textiles en fonction de leur photovieillissement accéléré. Dans un deuxième temps et dans l’optique de développer des textiles ignifuges, nous avons montré que l’immobilisation des LIs à la surface des textiles peut être réalisée par le procédé sol-gel. Pour ce faire nous avons tout d’abord synthétisé des liquides ioniques à partir d’un alcoxyde de silicium halogéné. Le sel obtenu est ensuite greffé sur des matrices textiles par le procédé sol- gel.Enfin, la dernière partie de l’étude consiste en la synthèse de fluorophores organiques par un procédé utilisant le couplage de type Heck. Leurs propriétés de photoluminescence ont été étudiées. Nous avons ainsi pu les greffer sur des surfaces pour développer des traceurs textiles fluorescents et des sondes pH fluorescentes.This work consists to provide a functionalization of textile surfaces by the sol-gel process using alcoxysilanes. The final aim is to impart water repellent, flame retardant and fluorescent features to textile surfaces. Firstly, the effects of synthesis parameters such as the concentration of the alcoxysilanes and the impregnation time of the fabrics in the solution (sol) prepared have been thoroughly investigated. Then, we have prepared a silica modified sol which is expected to induce a water repellent feature to textile. To investigate the water repellency under practical conditions, the common “rain test” was used according to AATCC test method 22-2005 also mechanical properties of treated un untreated textile was studied according to ISO 13934. Furthermore, thermal properties of sol-gel modified textiles were investigated and their water repellency abilities were assessed and compared after photo ageing upon UV irradiations.Secondly, we have showed that the immobilization of ionic liquids onto the surface of textile fabrics can be achieved by the sol-gel process, which is of a growing interest due to its simplicity and flexibility. For this aim, two ionic liquids were synthesized using halogenated alkoxysilane, and then grafted onto the cotton fabrics by sol- gel process .The functionalized cotton fabrics exhibit good water repellency and flame stability. Finally, a fluorophores bearing phenolic hydroxyl and pyridinium end groups have been synthesized and grafted into cellulosic fiber by sol -gel process. This fluorophores have been firstly synthesized by double Heck couplings, and then we have studied their photo physical behavior as function of their concentration both in ethanol and in the textile. We have also grafted the fluorophores in cellulosic textile by sol gel method to have fluorescent and PH-sensitive properties

Immobilisation of bacteria onto magnetic nanoparticles for the decolorisation and degradation of azo dyes

International audienceAzo dyes are widely used in industries and their release in the environment contributes to the pollution of effluents. The authors aim to develop a new eco-friendly water treatment method for the degradation of azo dyes based on in situ magnetic separation and immobilisation of bacterial cells. The immobilisation was achieved using superparamagnetic Fe3O4 nanoparticles and offers the possibility of reusing bacteria by magnetic separation for several degradation cycles. The iron–oxide nanoparticles were synthesised by reverse co-precipitation. The Gram-positive bacteria Bacillus subtilis were immobilised using iron–oxide nanoparticles by adsorption and then separated with an external magnetic field. Transmission electron microscopy observation showed that the particles' diameter was ∼20 nm with a narrow size distribution. Moreover, the iron–oxide nanoparticles were adsorbed onto the surface in order to coat the cells. B. subtilis has proved its ability to decolorise and degrade several azo dyes at different values of pH, with the highest decolorisation rate for Congo red. Furthermore, immobilised cells have a degradation activity similar to that of free cells. The system provided a degradation rate up to 80% and could be reused for seven batch cycles

Treatment of cotton fabrics by ionic liquid with PF6- anion for enhancing their flame retardancy and water repellency.

International audienceIn the present study, we report a new process for modifying cellulosic fabrics by using ionic liquids. To this aim, 1-methylimidazolium chloride propyltriethoxysilane and 1-pyridinium chloride propyltriethoxysilane salts were synthesised. Then, the cotton fabrics were treated with sols containing these salts by the pad-dry-cure process. Finally, the treated fabrics were impregnated in a diluted solution of HPF6 to perform the metathesis reaction. The morphology and chemical composition of treated and untreated fabrics were analysed by scanning electron microscopy, elemental analysis and infrared spectroscopy. The droplet shape analysis confirmed that the water repellency of the fabrics was significant after surface modification. The flame retardancy was also enhanced by using the PF6 anion. Thermogravimetric analysis was used to assess the thermal stability of these treated fabrics in air

Luminescent hybrid coatings prepared by a sol–gel process for a textile-based pH sensor

International audienceFluorene- and stilbene-based fluorophores were synthesized and characterized by NMR, IR, and mass spectroscopy (ESI-MS). These fluorescent dyes were coated onto cotton fabrics by the sol–gel method using tetraethylorthosilicate (TEOS) and propyltriethoxysilane (PTES) as silica precursors. Herein, the optical properties of the synthesized compounds and the elaborated fabrics were studied. The luminescent properties of the fluorophores were examined in three forms: as a powder, dissolved in ethanol, and grafted onto the fabric by the sol–gel method. Furthermore, the effect of the fluorophore concentrations in the sol–gel solution on the fluorescence properties of the elaborated hybrid coatings was investigated. The synthesized fluorophores exhibited good pH sensitivity and a strong wavelength shift in acidic or basic media, ascribed to the protonation–deprotonation of the phenolic groups and pyridine of the fluorophore molecules. Alongside this, we successfully developed pH-sensitive fluorescent textiles and tested their efficiency in different pH media

Immobilization of Bacillus licheniformis using Fe3O4@SiO2 nanoparticles for the development of bacterial bioreactor

International audienceIn the biotechnology field, nanoparticles with a strong magnetic moment can bring attractive and novel potentialities. They are detectable, manipulable, stimulable by a magnetic field and they could be applied as nano-tracers for medical imaging and nano-vectors for transporting therapeutic agents to a target. For our part, we applied Fe3O4 nanoparticles to immobilize bacteria of Moroccan strains in order to develop bacterial bioreactor. For this aim, we got through the synthesis and characterization of magnetite Fe3O4 nanoparticles by co-precipitation in basic medium. The obtained nanoparticles were encapsulated in silica by sol-gel process. The results of this step allowed us to use Fe3O4@SiO2 nanoparticles to immobilize Bacillus licheniformis by adsorption and separate it magnetically. The principle of this system gives us the opportunity to develop a bacterial bioreactor for industrial applications

Performance evaluation of polymer electrolyte membranes based on hydrogen sulfite ionic liquid for application in direct methanol fuel cell (DMFC)

Series of proton conductive membranes were prepared by mixing different weight ratio of 3-hexyl-1-methylimidazolium hydrogensulfite ([C6C1Imi][HSO3]), and N-hexyl-pyridinium hydrogensulfite ([C6Py][HSO3]) ionic liquids with poly vinyl alcohol (PVA) polymer. To characterize the PVA-ILs membranes, different methods have been used such as X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and scanning electron microscope (SEM). Moreover, the water uptakes, ion exchange capacity, methanol permeability, and proton conductivity of prepared PVA membranes doped with different weight ratio of ILs have been investigated to find the optimum formulation to use as electrolytes membranes for direct methanol fuel cell. The proton conductivity and the ion exchange capacity were improved as the ILs content increased. At 25 °C, The PVA-60 wt.% of [C6C1Imi][HSO3] membrane had a maximum proton conductivity of 17,47 mS.cm−1, and a methanol permeability of 8.17 10−7 cm2.s − 1. Mechanical and thermal data confirmed that addition of ILs improve the membrane flexibility and thermal stability up to 200 °C

Sol-gel based water repellent coatings for textiles.

International audienceSurfaces of cotton, polyester (PES) and polyamide (PA) fabrics have been modified by the sol–gel process in order to achieve silica based hybrid coatings onto the fibers for enhancing their water repellency, thermal stability and mechanical properties. The effects of synthesis parameters such as the concentration of the alkoxysilane used as main precursor, the chloropropyltriethoxysilane (CPTS), and the impregnation time of the fabrics in the solution (sol) prepared have been thoroughly investigated, aiming at the optimization of the targeted properties. Scanning electron microscopy images of the sol–gel treated fabrics exhibit significant differences from the untreated ones. The amount of silicon deposited onto the fabrics was determined by inductively coupled plasma atomic emission spectroscopy. The droplet shapes analysis confirmed that the water repellency of the fabric was dramatically improved after sol–gel treatment. The breaking strengths of the PES and PA fabrics coated with CPTS sols increase with higher sol concentration. Thermogravimetry analyses have been used to assess the thermal stability of treated fabrics. Finally, the influence of accelerated artificial photoageing on water repellency properties was investigated

Effect of Eu3+ and Tb3+ ions concentration on the mechanical, structural, and photoluminescence properties of phosphate glass fibers

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