Electromagnetic wave absorption properties of carbon-manganese microparticles/epoxy resin for aerospace shielding

Full text: The preparation of carbon materials from natural polymers such as lignin has raised greater interest for reasons of sustainability, besides its fast and simple preparation. The research was focused on the microwave electromagnetic shielding effectiveness of carbon/manganese (C-Mn) microparticles compounds in a system of C-Mn@epoxy resin. Sustainable C-Mn microparticles were synthesized from the residue of Kraft paper and pulp industry, called black liquor, polymerized with formaldehyde, resorcinol and manganese as a metallic element additive. The electromagnetic wave absorption parameters such as reflection loss (RL), complex permittivity and complex permeability [1], were obtained by measurement of the S-parameters (S₁₁, S₂₁, S₂₂, and S₁₂,) using a VNA equipment (waveguide method) in the frequency range of 8.2 – 12.4 GHz (X-Band). Furthermore, structural and morphological analyses were performed using Scanning Electronic Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (DRX). Characterizations showed presence of carbon and manganese on the bulk C-Mn material. The objective of this work was the development of electromagnetic shielding based on C-Mn/epoxy resin matrix composites with the addition of different concentrations, varying from 10 to 70 wt%, of C-Mn microparticles. Besides, different microparticles granulometries were investigated, C-Mn > 63 μm, 53 < C-Mn < 63, 25<C-Mn < 53 and Mn < 25 μm; keeping the specimen thickness fixed at 2.0 mm. The results obtained will be analyzed and the shielding effectiveness will be selected according to its efficiency, relating its efficiency to granulometry. References: [1] Sadiku, M. N. O., Elements of electromagnetics. 3 Ed, (2000). (author)