Electromagnetic, morphological and structural characterization of microwave absorbers based on POMA/magnetic filament composites

Electromagnetic, morphological and structural characterization of microwave absorbers based on POMA/magnetic filament composites

Author Pinto, Simone de Souza Autor UNIFESP Google Scholar
Barros Machado, Joao Paulo Google Scholar
Gomes, Newton A. S. Google Scholar
Rezende, Mirabel Cerqueira Autor UNIFESP Google Scholar
Abstract This study aims to combine dielectric and magnetic properties of different materials in an unique composite. For this, poly(o-methoxyaniline), POMA, was chemically synthesized in situ on magnetic metallic filaments (MF). The obtained composite was inserted into an epoxy resin matrix in the proportions of 40, 50 and 70%, in weight (wt%). The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electromagnetic measurements. On the last case, the measurements considered the reflectivity and the complex parameters of electrical permittivity and magnetic permeability in the frequency range of 8.2-12.4 GHz (X-band). Specimens with different thicknesses were evaluated by reflectivity. XRD results show that the filaments are based on Fe-a steel and SEM analyses show the good incorporation of POMA/MF in the epoxy resin composite. The complex parameters show that the real component of permittivity shows the largest variation with the POMA/MF concentration increasing in epoxy resin and the loss tangent indicates that the magnetic losses are preponderant on dielectric ones. The reflectivity measurements show that the 5 mm-specimen with 50 wt% of POMA/MF presents the best result of attenuation (-21.5 dB, i.e. above 99% of attenuation). Already, the sample containing 70 wt% shows the worst performance (up to -9.0 dB). The increase of POMA/MF concentration in epoxy resin confers maximum attenuation values for less thick specimens. The results show that the combination of dielectric and magnetic materials in a composite contributes for the improvement of microwave absorbing performance, and extends the possibilities of RAM processing with different characteristics. (C) 2017 Elsevier B.V. All rights reserved.
Keywords Metallic filaments
POMA
Composites
Microwave absorber
xmlui.dri2xhtml.METS-1.0.item-coverage Amsterdam
Language English
Sponsor Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)
CNPq
Grant number CNPq: 303287/2013-6
Date 2018
Published in Journal Of Magnetism And Magnetic Materials. Amsterdam, v. 449, p. 406-414, 2018.
ISSN 0304-8853 (Sherpa/Romeo, impact factor)
Publisher Elsevier Science Bv
Extent 406-414
Origin http://dx.doi.org/10.1016/j.jmmm.2017.09.073
Access rights Closed access
Type Article
Web of Science ID WOS:000415976800058
URI https://repositorio.unifesp.br/handle/11600/54105

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