Antibacterial Properties of Functional Polyamide 6.6

Polyamide 6.6 multifilaments are grafted with the monomer N-allyliminodiacetic acid for the purpose of removal of some heavy metal ions from their aqueous solutions by forming its metal chelate especially with Ag+ ion. Such a fibrous chelate-forming resin has been used with success due to its large surface area, which contains an important metal chelate-forming functional group, where metal ions are adsorbed or desorbed on its surface, and therefore having an improved adsorption and desorption capability. In previous work, chelate-forming fibre was characterised by ICP-AES analysis according to the digestion method by microwave. The antibacterial activity of the prepared fibre is investigated with Escherichia coli bacteria as reference, according to the zone of inhibition method in agar medium. The material used as reference without metal does not present any effect on E. coli. However, the chelateforming fibres with Ag+ have a strong bactericidal effect, even with a low concentration of silver ions. These modified materials can be used as highly effective bactericidal composites that may be used in future applications for the production of antimicrobial textiles, papers or polymer material

Preparation And Properties Of Bionanocomposite Films Reinforced With Nanocellulose Isolated From Moroccan Alfa Fibres

Nanocellulose (NC) were extracted from the Moroccan Alfa plant (Stipa tenacissima L.) and characterised. These Alfa cellulosic nanoparticles were used as reinforcing phase to prepare bionanocomposite films using carboxymethyl cellulose as matrix. These films were obtained by the casting/evaporation method. The crystallinity of NC was analysed by X-ray diffraction, the dimension of NC by atomic force microscopy, molecular interactions due to incorporation of NC in carboxymethyl cellulose (CMC) matrix were supported by Fourier transforms infrared (FTIR) spectroscopy. The properties of the ensuing bionanocomposite films were investigated using tensile tests, water vapour permeability (WVP) study and thermogravimetric analysis. With the progress of purification treatment of cellulose, the crystallinity is improved compared to the untreated fibres; this can be explained by the disappearance of the amorphous areas in cellulose chain of the plant. Consequently, the tensile modulus and tensile strength of CMC film increased by 60 and 47%, respectively, in the bionanocomposite films with 10 wt% of NC, and decrease by 8.6% for WVP with the same content of NC. The NC obtained from the Moroccan Alfa fibres can be used as a reinforcing agent for the preparation of bionanocomposites, and they have a high potential for the development of completely biodegradable food packaging materials

Development and Characterization of Phosphate Glass Fibers and Their Application in the Reinforcement of Polyester Matrix Composites

International audienceThis study focused on the production and characterization of phosphate glass fibers (PGF) for application as composite reinforcement. Phosphate glasses belonging to the system 52P2O524CaO13MgO (11-(X + Y)) K2OXFe2O3YTiO2 (X:1, 3, 5) and (Y:0.5, 1) were elaborated and converted to phosphate glass fibers. First, their mechanical properties and chemical durability were investigated. Then, the optimized PGF compositions were used afterward as reinforcement for thermosetting composite materials. Polyester matrices reinforced with short phosphate glass fibers (sPGF) up to 20 wt % were manufactured by the contact molding process. The mechanical and morphological properties of different sPGF-reinforced polyester systems were evaluated. The choice between the different phosphate-based glass syntheses (PGFs) was determined by their superior mechanical performance, their interesting chemical durability, and their high level of dispersion in the polyester matrix without any ad sizing as proven by SEM morphological analysis. Moreover, the characterization of mechanical properties revealed that the tensile and flexural moduli of the developed polyester-based composites were improved by increasing the sPGF content in the polymer matrix in perfect agreement with Takayanagi model predictions. The present work thus highlights some promising results to obtain high-quality phosphate glass fiber-reinforced polyester parts which can be transposed to other thermosetting or thermoplastic-based composites for high-value applications

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

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Effect of fluorescein concentration on morphological, structural, and photoluminescence properties of glass fibers coated with organic-inorganic hybrid films via sol-gel

International audienceIn the realm of fiber surface functionalization, the sol-gel method is a prominent technique. This study aims to demonstrate its effectiveness in depositing fluorescent organic-inorganic hybrid coatings on glass fiber substrates with micron-scale diameter. The coatings were synthesized using chloropropyltriethoxysilane (CPTS) as a Si-precursor and fluorescein (FL) as the fluorescent fluorophore, with varying concentrations of FL in the hybrid sol (0.1–0.2%). SEM, AFM, and FTIR analyses confirmed the deposition of the coatings and structural modifications. Photoluminescence (PL) properties were investigated, showing yellowish-green emission. The fluorescence intensity of PL spectra increased with FL concentration, with maximum quantum yields at 0.2% FL. Samples coated with this concentration were then exposed to UV-visible irradiation at different exposure times to study the influence of photoaging on their structural and photoluminescence properties. This study successfully demonstrates the deposition of the fluorescent organic-inorganic hybrid coatings on the glass fibers surface using the sol-gel method, resulting in notable structural modifications and enhanced photoluminescence properties. Additionally, the integration of new molecules into this hybrid sol on glass fiber surfaces can offer the possibility of developing novel or improved properties that can be applied in various fields

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

Stipa tenacissima L.: A New Promising Source of Bioactive Compounds with Antioxidant and Anticancer Potentials

Background: Stipa tenacissima L. (S. tenacissima), called Esparto grass, is a cultivated species used for industrial purposes, including textile production. This species has never been studied for its medical potential before, nor has it been used in traditional medicines. It is thus fitting that the present study aimed to investigate the pharmacological potential of S. tenacissima. To achieve this goal, this work was conducted to study the chemical composition, antioxidant properties, and antiproliferative effects of S. tenacissima against cancerous cell lines, including the human colorectal adenocarcinoma cell line (HT-29) and human breast adenocarcinoma cell line (MDA-MB-231). Fractionation and characterization of S. tenacissima extract showed the presence of promising bioactive fractions. The fractions obtained from S. tenacissima extract exhibited interesting antioxidant properties, with IC50 values ranging from 1.26 to 1.85 mg/mL. All fractions, such as F1, F2, F3, and F4, induced an important antiproliferative effect on the cancer cell lines MDA-MB-231, scoring IC50 values ranging from 63.58 ± 3.14 to 99.880 ± 0.061 µg/mL. These fractions (F1, F2, F3, and F4) also exhibited a potent antiproliferative effect versus HT-29 cell lines, with IC50 values ranging from 71.50 ± 4.97 to 87.500 ± 1.799 µg/mL. Therefore, S. tenacissima could constitute a new natural source of bioactive compounds that can be used for therapeutic purposes to fight cancer and free radical damage