Electromagnetic properties of Carbon-Graphene Xerogel, Graphite and Ni-Zn Ferrite composites in polystyrene matrix in the X-Band (8.2 – 12.4 GHz)

Matheus Carvalho Bispo,Antonio Carlos Da Cunha Migliano,Míriam Kasumi Hwang Yassuda,Maurício Ribeiro Baldan,Gisele Amaral-Labat,Jorge Tadao Matsushima,Braulio Haruo Kondo Lopes,Roberto Camargo Portes,Beatriz Carvalho Da Silva Fonseca

doi:10.1590/s1517-707620210002.1267

Abstract

The electromagnetic properties of Carbon-Graphene Xerogel (CGX), Flaky graphite (GR) and Nickel-Zinc ferrite (FeNiZn) composites in polystyrene (PS) matrix were studied in the X-Band range (8.2 – 12.4 GHz). In this work the Expanded Polystyrene (EPS) waste material was processed into polystyrene through the recycling of EPS. The polystyrene obtained was utilized as dielectric matrix, mainly because PS is a well-known organic polymer that presents low dielectric loss and light weight, which contribute to applications in composites for the aerospace field. In order to produce the final composite specimens, the CGX additive was previously synthesized through a sustainable method that employed the use of waste from the paper and pulp industry (black liquor). Afterwards, the morphological and structural analysis were made through Scanning Electron Microscope (SEM) and Raman Spectrometer, respectively. On the other hand, the magnetic ferrite material, FeNiZn, was obtained for the composite production through calcination, whereas the GR utilized was commercially obtained. It was observed that the increase of CGX and GR influenced on the increase of the Complex Permittivity, and that 10 wt% CGX + 50wt% FeNiZn composite sample demonstrated an absorption peak at 10.5 GHz. The results are relevant concerning the recycling of EPS waste through its use as dielectric matrix, thus developing greener and low-weight composite materials to be used in microwave applications.

Highlights

Electromagnetic Radiation Absorbing Composites (ERAC) have been studied in the recent years [1- 3] due to their applications in the aerospace, military and engineering fields, such as in electromagnetic shielding and sandwich structures
The polystyrene obtained was utilized as dielectric matrix, mainly because PS is a wellknown organic polymer that presents low dielectric loss and light weight, which contribute to applications in composites for the aerospace field
It was observed that the increase of Carbon-Graphene Xerogel (CGX) and GR influenced on the increase of the Complex Permittivity, and that 10 wt% CGX + 50wt% FeNiZn composite sample demonstrated an absorption peak at 10.5 GHz

Summary

Introduction

Electromagnetic Radiation Absorbing Composites (ERAC) have been studied in the recent years [1- 3] due to their applications in the aerospace, military and engineering fields, such as in electromagnetic shielding and sandwich structures These areas often require materials with low density, heat insulation and chemical stability properties. It is known that textural characteristics of the CX such as surface area, pore volume and pore size distribution depend strongly on the experimental conditions of the synthesis method chosen [9] Obtaining this CX is more simplified than other types of carbonaceous materials, such as carbon aerogels. In this work Carbon-Graphene Xerogels (CGX) were materials synthesized through a less costly method which employs the use of waste from the paper and pulp industry, the Kraft black liquor This sustainable method allowed the incorporation of graphene in the CX structure, bringing the electrical properties of graphene to composites

Methods

Results

Conclusion