Browsing by Author "Ourari, A"

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ELECTROCHEMICAL AND THEORETICAL STUDIES INFLUENCING THE EFFECT OF HYDROXYL POSITION OF TETRAPHENOLIC SCHIFF BASES TOWARDS CORROSION INHIBITION OF MILD STEEL IN 1M HCl
(university of el oued/جامعة الوادي, 2018-09-01) Kheniche, A; Ourari, A; Dakhouche, A; Ghanem, A; Meguellati, K; Min, W
The effect of three tetrahydroxylated Schiff bases as N,N-bis(2,3-dihydroxybenzylidene)-4,4’-diphenylmethane, N,N-bis(2,4-dihydroxybenzyl- idene)-4,4’-diphenylmethane and N,N-bis(2,4-dihydroxybenzylidene)-4,4’-diphenylmethane were studied as inhibitors for mild steel in 1M HCl medium. The experiments were performed using potentiodynamic polarization. This inhibition proved an efficient increase according the position of second hydroxyl of salicylaldehyde suggesting that this inhibition is dependent on concentration and the compound nature. Among these position-isomers, the best inhibition efficiency was obtained with p-hydroxylated (94%) at 1mM. Tafel plots of these inhibitors are the mixedtype, their adsorption is spontaneous obeying to Langmuir’s isotherm. AFM/SEM-EDS characterized metal surface. DFT-calculations and molecular dynamics simulations are correlated to inhibition efficiency obtained.
PREPARATION AND CHARACTERIZATION OF POLYPROPYLENE/ PLASTICIZED CORN STARCH BLENDS: EFFECT OF ORGANO-MAGHNITE CLAY AND COMPATIBILIZER ON THE MORPHOLOGICAL, MECHANICAL AND THERMAL PROPERTIES
(university of el oued/جامعة الوادي, 2018-09-01) Smail, D; Djellouli, B; Ourari, A; Doufnoune, R; Fleutot, S
A biobased nanocomposite was prepared from polypropylene (PP) and thermoplastic starch (TPS). Different percentages of polypropylene-grafted-maleic anhydride are added to the two phases to improve their compatibility. This system was reinforced with organoclay, modified by alkylammonium. The compatibilizer effect and TPS on morphology and properties of PP/organoclay nanocomposites obtained by melt compounding are studied. A good dispersion of filler into polymer matrix is demonstrated by X-ray diffraction. Exfoliated structure with improved compatibility between PP and TPS are obtained using MA-g-PP compatibilizer. Scanning electron microscopy proved strong interfacial adhesion between the components. 7% wt of MA-g-PP compatibilizer and 30% wt of TPS without compatibilizer induce an increase in modulus. Tensile strength and elongation decreased in all materials. TGA-DTA showed an increase in decomposition temperature of compatibilized materials.
SURFACE MODIFICATION OF SILICA NANOPARTICLES BY MEANS OF SILANES: EFFECT OF VARIOUS PARAMETERS ON THE GRAFTING REACTIONS
(university of el oued/جامعة الوادي, 2019-01-01) Bounekta, O; Doufnoune, R; Ourari, A; Riahi, F; Haddaoui, N
The adsorption of four silanes, namely: N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTMS), 3-methacryloxypropyltrimethoxysilane (MPTMS), allyltrimethoxysilane (ATMS), N-2-[(N-vinylbenzylamino)ethyl]-3-aminopropyltrimethoxysilane hydrochloride (CVBS) onto the surface of silica nanoparticles has been studied using water/ethanol (5/95, v/v) mixture. Four experimental parameters were explored for the grafting of the silanes: pH, concentration, time, and temperature. Possible interactions between the silanes and the surface of silica were investigated by means of FT-IR Spectroscopy. The FT-IR analyses confirmed the effectiveness of the silanization of the silica surface. The amount of the adsorbed silane on the silica nanoparticles appeared to be influenced by the initial concentration of the silane, pH, time and temperature of modification.
SYNTHESIS, ELECTROCHEMICAL AND HETEROGENEOUS ELECTROCATALYTIC BEHAVIORS OF A NOVEL NON SYMMETRICAL COPPER(II) COMPLEX
(university of el oued/جامعة الوادي, 2019-01-01) Bounab, N; Ourari, A; Derafa, W; Aggoun, D
We describe in this paper the synthesis of new unsymmetrical tetradentate copper(II) Schiff base complex, prepared from tridentate Schiff base ligand (HL) and pyridine molecule. This new copper complex was identified by various physicochemical characteristics such as elemental analysis (EA), FT-IR, UV-Vis, XPS analysis and thermogravimetry (TG/DTG). The electrochemical behavior of the copper(II) complex was investigated by cyclic voltammetry in N,N-dimethylformamide (DMF). These experiments have been allowed to obtain new conducting polymeric films, prepared by successive cycling at the suitable potentials. These polymeric films containing metallic centers were studied to evaluate their electrocatalytical performances in which copper (II) ions were used as electrocatalysts in the heterogeneous conditions for the electroreduction of 1,4-dibromobutane.