Entity

Time filter

Source Type

Rabat, Morocco

Amer W.,MAScIR Foundation | Abdelouahdi K.,French National Center for Scientific Research | Ramananarivo H.R.,MAScIR Foundation | Fihri A.,MAScIR Foundation | And 6 more authors.
Materials Science and Engineering C | Year: 2014

In this report new hybrid materials based on brushite-alginate and monetite-alginate were prepared by self-assembling alginate chains and phosphate source ions via a gelation process with calcium ions. The alginate served as nanoreactor for nucleation and growth of brushite or/and monetite due to its gelling and swelling properties. The alginate gel framework, the crystalline phase and morphology of formed hybrid biomaterials were shown to be strongly dependent upon the concentration of the phosphate precursors. These materials were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX). © 2013 Elsevier B.V.


El Achaby M.,University Mohammed Polytechnique | El Miri N.,Hassan II University | Snik A.,Hassan II University | Zahouily M.,Hassan II University | And 4 more authors.
Journal of Applied Polymer Science | Year: 2016

Biopolymer nanocomposite films were prepared by adding exfoliated graphene oxide nanosheets (GOn) into carboxymethyl cellulose (CMC) at low and high GOn loadings (0.4-7 wt %). As firstly evidenced by viscosity of film-forming solutions, microscopic observations and infrared spectroscopy measurements, it was found that the GOn form a three-dimensional network throughout strong interfacial interactions with CMC, confirming that the GOn were well dispersed within the CMC, even at high GOn content, owing to the presence of several multifunctional groups on both phases which ensured the high compatibility between them. The topography of as prepared films was characterized by atomic force microscopy measurements showing that the films have a smooth surface with a very low average roughness for all range of GOn contents. Furthermore, the thermal stability, glass transition temperature, and tensile properties of nanocomposite films were gradually increased with increasing of GOn contents. By adding 7 wt % GOn, 18% increases of thermal stability, 17% of glass transition temperature, 623% of Young's modulus, and 268% of tensile strength were achieved. This work produced structured CMC-based nanocomposite films containing low and high loadings of well-dispersed GOn. The high performances of these films can be expected to have potential in biomaterials or packaging materials applications. © 2015 Wiley Periodicals, Inc.


Neqali A.,Cadi Ayyad University | Belboukhari A.,LPCMA | Bensaid H.,LPCMA | El Bouari A.,LPCMA | And 4 more authors.
Applied Physics A: Materials Science and Processing | Year: 2016

A new rare earth ferroelectric tetragonal tungsten bronze compound with general formula Ba2.15−xNa0.7+xNb5−xWxO15 (x = 0.25) was elaborated as ceramic and investigated using X-ray diffraction and dielectric measurements. The results show a tetragonal phase with the space group P4bm. Special emphasis was done to characterize diffuse phase transition (DPT) that occurs close to 472 °C. Using dielectric measurements in a frequency range of (10 Hz–1 MHz) and in a temperature range (25–550 °C), we have shown that the real part of the permittivity close to DPT is well described by Santos–Eiras phenomenological model. Space charge polarization, relaxation phenomena and free charges conductivity have been analyzed using dielectric, impedance spectroscopy and Nyquist plots showed non-Debye (polydispersive) type relaxation. In paraelectric phase, the Arrhenius activation energies were determined. Frequency dependence of ac conductivity at different temperatures follows the Jonscher’s universal law (Jonscher et al. in J Mater Sci 20:4431, 1985). © 2016, Springer-Verlag Berlin Heidelberg.


Hassine A.,Hassan II University | Bouhrara M.,Nazarbayev University | Sebti S.,Hassan II University | Solhy A.,University Mohammed Polytechnique | And 6 more authors.
Current Organic Chemistry | Year: 2014

This report explores Suzuki-Miyaura coupling under microwave irradiation, using a new generation of catalyst that is based on natural phosphate (NP) impregnated by palladium. This catalyst was prepared by the treatment of natural phosphate with bis(benzonitrile)palladium(II) chloride in acetone at room temperature. The catalyst displayed high catalytic activity for the Suzuki-Miyaura coupling of aryl bromides and chlorides with aryl boronic acids in pure water and with the use of microwave irradiation. The low-cost and availability of the solid support, mild reaction conditions, high yields of desired products, recyclability of the catalyst and short reaction times are the notable features of these methods. © 2014 Bentham Science Publishers.


El Achaby M.,Center For Advanced MaterialsUniversite Mohammed PolytechniqueLot 660 Hay Moulay Rachid43150Ben Guerir Morocco | El Miri N.,Hassan II University | Snik A.,Hassan II University | Zahouily M.,Hassan II University | And 4 more authors.
Journal of Applied Polymer Science | Year: 2015

Biopolymer nanocomposite films were prepared by adding exfoliated graphene oxide nanosheets (GOn) into carboxymethyl cellulose (CMC) at low and high GOn loadings (0.4-7 wt %). As firstly evidenced by viscosity of film-forming solutions, microscopic observations and infrared spectroscopy measurements, it was found that the GOn form a three-dimensional network throughout strong interfacial interactions with CMC, confirming that the GOn were well dispersed within the CMC, even at high GOn content, owing to the presence of several multifunctional groups on both phases which ensured the high compatibility between them. The topography of as prepared films was characterized by atomic force microscopy measurements showing that the films have a smooth surface with a very low average roughness for all range of GOn contents. Furthermore, the thermal stability, glass transition temperature, and tensile properties of nanocomposite films were gradually increased with increasing of GOn contents. By adding 7 wt % GOn, 18% increases of thermal stability, 17% of glass transition temperature, 623% of Young's modulus, and 268% of tensile strength were achieved. This work produced structured CMC-based nanocomposite films containing low and high loadings of well-dispersed GOn. The high performances of these films can be expected to have potential in biomaterials or packaging materials applications. © 2015 Wiley Periodicals, Inc.

Discover hidden collaborations