Publications Scientifiques
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Item Synthèse, Caractérisation Et étude De Comportement Des Nanocomposites à Base De Poly (n-isopropylacrylamide)/montmorillonite Sodique(Université M'Hamed Bougara Boumerdes, 2015) Seddiki, N.; Aliouche, DjamelDans ce travail nous avons procédé à la synthèse d'une série des nanocomposites à base de poly (N-isopropylacrylamide) (PNIPAAm) avec la montmorillonite sodique (MMT-Na), la polymérisation se fais par voie in situ, nous avons fais varier le taux d’argile de (0-4)% en poids et la concentration de polymère à été fixé a 8% en poids. L’ensemble de ces nanocomposites (PNIPAAm/MMT-Na) à été caractérisé en spectroscopie infrarouge(FTIR), en Diffraction des rayons X (DRX) et par microscopie électronique en transmission (MET), leur comportement en absorption à été étudié par leur gonflement dans différentes solution et en fonction de la température, le nanocomposite obtenu est un nanocomposite intercalé-exfolié, le gonflement diminue avec l’augmentation de taux d’argile pour (0-2)%, à un taux d’argile de 4% un comportement inverse est observé, la température inférieure de solution (LCST) de poly(N-isopropylacrylamide) PNIPAAm ne varie pas avec la concentration d’argile.Item Synthesis, characterization and swelling behavior of pH-sensitive polyvinylalcohol grafted poly(acrylic acid-co-2-acrylamido-2-methylpropane sulfonic acid) hydrogels for protein delivery(Springer, 2023) Hocine, Salima; Ghemati, Djamila; Aliouche, DjamelThe aim of the current study was to fabricate a pH-sensitive hydrogels for controlled release of Bovine serum albumin (BSA) protein. In this research work, polyvinylalcohol grafted poly(acrylic acid-co-2-acrylamido-2-methylpropane sulfonic acid) (PVOH-g-poly(AA-co-AMPS)) hydrogels with varying AA/AMPS molar ratio were synthesized through free radical graft copolymerization of partially neutralized acrylic monomers and characterized by Fourier transform infrared spectroscopy, Elemental analysis, X-ray diffraction, and Scanning electron microscopy, thermogravimetric analysis. Then, mechanical proprieties of hydrogels were investigated, and drug release behavior with Bovine serum albumin (BSA) as model drug was studied in vitro. The effect of AA/AMPS molar ratio, pH media on the swelling property of hydrogels was optimized. Results indicated that the strong interaction in the hydrogels resulted in the formation of a more stable copolymer. The high values of the grafting percentage which exceeds 800% confirmed the high performance of the grafting and the successful synthesis. Grafting AMPS onto PVOH/AA improved both thermal stability and mechanical properties of hydrogel. The hydrogel is simultaneous sensitive to pH and ionic strength; the swelling ratio maximizes at pH 6.8 medium and shrinks at pH 1.2, and decreases as the ionic strength increases; the swelling dynamic mechanism was explained well by Fickian diffusion and Schott’s pseudo-second-order models. Different kinetic models were applied, and it has been observed that release profile of BSA best followed the Hixson–Crowell for the release of drug in all release media. However, Zero order and Korsmeyer–peppas models only for pH 1.2 and pH 7.4. The swelling of the hydrogels and release of BSA from the drug loaded hydrogels occurred through non-Fickian diffusion mechanism. It is believed that this hydrogel could be potentially used for localized drug deliveryItem Polyacrylamide Grafted Xanthan: Microwave-Assisted Synthesis and Rheological Behavior for Polymer Flooding(MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations., 2021) Chami, Souheyla; Joly, Nicolas; Bocchetta, Patrizia; Martin, Patrick; Aliouche, DjamelApplication of polymer-flooding systems in secondary and tertiary oil recovery represents a real challenge for oil industry. In this work, our main objective is to explore possibilities of making use of xanthan-g-polyacrylamide for polymer flooding in a particular Devonian oilfield of medium salinity. The graft polymer was synthesized by using microwave-assisted graft copolymerization reaction of acrylamide on xanthan. The synthesized copolymer with optimized grafting parameters has been characterized by Infrared Spectroscopy and Thermal Analysis (DSC). Rheological analysis by steady shear and oscillatory flow experiments have been subsequently performed for xanthan and grafted xanthan under reservoir conditions. In steady shear, as expected the grafted polymer solutions flow as shear-thinning materials and apparent viscosity showed good fits with Cross's model. The viscosity losses due to salinity or temperature are more controlled for the grafted xanthan compared to pristine xanthan. When the grafted polymer concentration is increased to 2000 ppm the losses were halved. In oscillatory shear, the copolymer solutions followed a global behavior of semi-dilute entangled systems; furthermore, all dynamic properties were influenced by the brine salinity. Compared to xanthan, the elastic properties of xanthan-g-polyacrylamide solutions have been significantly improved in saline media and the losses in elasticity of grafted polymer solutions are lower.Item Studies on equilibrium swelling, dye adsorption, and dynamic shear rheology of polymer systems based on chitosan-poly(vinyl alcohol) and montmorillonite(Taylor & Francis, 2019) Amri, Nedjla; Radji, Sadia; Ghemati, Djamila; Aliouche, DjamelChitosan-poly(vinyl alcohol)/clay membranes were prepared by physical blending. Thesehybrid systems were characterized through infrared spectroscopy, microscopy, swelling, andoscillatory rheology. Adsorption of a commercial reactive dye by these membranes was fur-ther studied. Results showed that more stable blend membranes were formed due to thestrong interaction in the polymers. These membranes showed substantial percent swellingin water and shrinking in saline solution. Adsorption analysis showed the ability of theblends to fix organic dyes, and to be used in liquid waste processing. In dynamic rheology,it was observed that all measured viscoelastic properties were influenced by polymer com-position and clay content. For all samples, results show a typical behavior of an entangledsystem in the case of low concentrated macromolecular viscoelastic fluids. The dynamicmoduli exhibited higher values for blends, compared with values of the pure polymers,which is an indication of good stability and tendency of gel formationItem Synthesis, characterization and rheological behavior of pH sensitive poly(acrylamide-co-acrylic acid) hydrogels(Elsevier B.V., 2017) Seddiki, Nesrinne; Aliouche, DjamelPoly(acrylamide-co-acrylic acid) poly(AAm-co-AAc) hydrogels were prepared by free radical polymerization initiated by redox initiators of ammonium peroxodisulphate (APS) and N,N,N′,N′-tetramethyl ethylene diamine (TEMED); N,N′-methylene bisacrylamide (BIS) was employed as a crosslinking agent. The copolymers were characterized by infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), dynamic rheology and swelling measurements. Results indicated that the strong interaction in the hydrogels resulted in the formation of a more stable copolymer. The single glass transition temperature (Tg) in sample suggested that the two polymers into the hydrogel have a good miscibility. The elastic modulus (G′) and linear viscoelastic region increased with increase in PAAc concentration. The oscillation time sweep study of the hydrogels exhibited a flat G′ indicating a stable structure and good mechanical strength. In the swelling measurements, the gels exhibited appreciable water uptake and were highly sensitive to pH environment. So the poly(AAm-co-AAc) hydrogel will have promising application in pharmaceutical use and in biomaterialsItem An enhanced immobilization of BSA biomolecule on anionic hydrogels: Swelling and adsorption modeling(Springer International Publishing, 2017) Angar, Nour Elhouda; Aliouche, DjamelThe three-dimensional structure of hydrogels plays a leading role in several areas of applications. The hydrogels are more and more used as systems of immobilized and controlled release of biomolecules in biotechnology and bio-pharmacy industries. To improve protein adsorption capacity in poly(acrylamide) hydrogels, maleic acid co-monomer was included into the reaction mixture during hydrogel synthesis. So, hydrogels of poly(acrylamide) and its copolymers with diprotic maleic acid were prepared by copolymerization and chemical crosslinking with N,N′-methylene bis-acrylamide. Swelling behavior in distilled water, in physiological saline and in bovine serum albumin (BSA) solutions was studied. Influence of initial BSA concentration on hydrogel swelling and BSA adsorption was investigated. The high amount of maleic acid present in the hydrogels has a significant effect on the swelling behavior and BSA adsorption. Results showed that the pH sensitivity of hydrogels resulted in the high amount of adsorbed BSA. The adsorption isotherms were described by Langmuir and Freundlich models. The thermodynamic parameter (ΔG ads 0) was determined for all obtained hydrogels. We demonstrated the favorable character and reversibility of the BSA adsorption processItem Study of the effect of UV aging on the mechanical properties of a geotextile based on polypropylene(American Institute of Physics Inc, 2018) Ghemati, Djamila; Rafa, Nadia; Aliouche, DjamelThe main objective of this work is to study the effect of aging by UV radiation on the physical and mechanical properties of two types of polypropylene-based non-woven geotextiles. First, a study of the physical, mechanical characteristics was carried out, followed by an aging test by ultraviolet radiation as a function of time in order to evaluate their mechanical characteristics before and after aging using standard tests. The results obtained show that: the mechanical properties such as the tensile strength of a geotextile depend on its areal density and its thickness, so the resistance to static and pyramidal punching increases with increasing geotextile thickness. A significant loss in tensile properties (tensile strength and elongation at break) of about 50% for a time of exposure of geotextiles to UV radiation for 300 h. Finally, it can be concluded that polypropylene geotextiles are sensitive to ultraviolet radiation. Therefore, in order to increase the service life of a geotextile, it is necessary to avoid exposure to light during storage and processing, or to add a stabilizerItem Optimization of the extraction of galactoglucomannans from Pinus halepensis(DE GRUYTER, 2020) Benouadah, Nacera; Pranovich, Andrey; Aliouche, Djamel; Labidi, Jalel; Willför, StefanThe effectiveness of pressurized hot-water extraction conditions for obtaining galactoglucomannans (GGMs) from Pinus halepensis suitable for applications like coatings and films packaging was investigated. For this purpose, high molar masses with high yields are required, presenting a serious challenge for hot-water extraction processes. The extraction of GGMs was carried out in an accelerated solvent extractor (ASE) and the isolation was performed by precipitation in ethanol. Three temperatures in the range 160–180 °C and five extraction times 5–90 min were tested in order to optimize extraction parameters of GGMs, avoiding thermal and chemical degradation in hot-water. Total dissolved solids (TDS) were determined gravimetrically after freeze-drying and weight average molar masses (Mw) were determined by high-performance size exclusion chromatography (HPSEC). Total non-cellulosic carbohydrates were determined by gas chromatography (GC) after acid methanolysis. Free monomers were additionally analyzed by GC. Lignin in water extracts was measured by an ultraviolet (UV) method. Acetic acid was determined after alkaline hydrolysis of acetyl groups and analyzed by HPSEC. The main parameters influencing the extraction processes of the GGMs, namely, extraction time and temperature were studied. Optimal extraction parameters of GGMs were identified at 170 °C and 20 min extraction time, with average Mw of extracted fraction of 7 kDa leading to a GGM yield of approximately 56 mg g−1o.d.m, corresponding to 6% on dry wood basis.Item Chemical characterization of pinus halepensis sapwood and heartwood(Taylor & Francis, 2018) Benouadah, Nacera; Aliouche, Djamel; Pranovich, Andrey; Willför, StefanItem Analysis of extractives from Pinus halepensis and Eucalyptus camaldulensis as predominant trees in Algeria(2017) Benouadah, Nacera; Pranovich, Andrey; Aliouche, Djamel; Hemming, Jarl; Smeds, Annika; Willför, Stefan