Optimization of multiroute synthesis for polyaniline-barium ferrite composites

Abstract

International audienceA comparative study of physicochemical and magnetic properties of Polyaniline-BaFe12O19 composites prepared by Solid-Based Polymerization (SBP) and by Aqueous-Based Polymerization (ABP) is carried out. The composites obtained by the latter method underwent a grinding to study the influence of shear stress. Thus, in a systematic approach, an investigation of stirring effect was done by synthesizing these composites using aqueous-based polymerization but without mechanical stirring. Different mass ratio of BaFe12O19 was used to explore their impact on composites properties. X-ray diffraction, FTIR, SEM, TGA, conductivity and vibrating sample magnetometer measurements were performed. Structural andmorphological investigations confirmed the presence of polyaniline and barium hexaferrite phase, which were in interaction in the composites regardless the polymerization route. The powder obtained by solid-based pathway revealed distinct particles with uniform distribution for various compositions (wt.%) of BaFe12O19 in Pani, while the composites obtained by aqueous-based polymerization presented agglomerated nanostructures. Thermogravimetric analysis exhibited an improved thermal stability for Pani-BaFe 12O19 obtained by solid-based route. The electric conductivity has displayed decreasing trend of DC conductivity with the increase of BaFe12O19 particles in the polymer matrix. Magnetic studies showed a ferromagnetic behaviour for all composites. The saturation magnetization monotonously increased with the increasing of BaFe12O19 amount. The magnetic properties of the powders were mainly related to the hexaferrite loading which was determined using measured magnetic data. These results revealed that magnetization saturation was dependent of volume fraction of ferrite in the composites which wassignificantly affected by the reaction medium and mechanical stirring. The powders obtained by solid-based polymerization manifested enhanced magnetic characteristics. The solventless reaction medium contributed to the increase of volume fraction of ferrite in the composite compared to the aqueous reaction medium. Moreover, the mechanical stirring during aqueous-based polymerization had an important influence on the volume fraction of ferrite since it prevented the dissolution of BaFe12O19 particles

Substitution effect of Me = Al, Bi, Cr and Mn to the microwave properties of polyaniline/BaMeFe11O19 for absorbing electromagnetic waves

“…Barium hexaferrite-polymer composites, if formed by Solid-Based Polymerization route, have better compositional homogeneity and narrow particle size distribution compared to the composites obtained by standard Aqueous-Based Polymerization method as shown in our previous work [18].…”

“…This enhancement in the thermal stability can be due to the ionic interactions of BaFe 12 O 19 with amine group of aniline. These interactions limit the freedom of the polymer chains by improving the thermal degradation of this latter [18].…”

“…As reported in the literature, the magnetic polarization is strongly dependent to the real particles loading in the formed composite. Actually, the used initial loading to prepare the samples can change after the polymerizations synthesis due to partial loss or dissolution during the fabrication as we have demonstrated in our previous study [18].…”

“…However, it is found that no much work has been reported on the dielectric and magnetic properties of trivalent iron substitution in barium ferrite-polymer composites in the high frequency region [21,22]. [18]. Initially, An-Cl and ferrite particles are ground in an agate mortar for 10 min.…”

“…The polymerization lasted for 24 h to complete the polymerization reaction at room temperature. The dark green product is washed by HCl (0.2 M) several times, filtered and then dried in a vacuum at 60 °C for 24 h. Since the effect of volume fraction has already been studied previously [18], we have fixed the volume fraction of ferrite at 10 %. Here, we are more interested to investigate the effect of the substitution iron on the properties of the composite.…”