Dielectric characterization of white birch–activated biochar composites: A sustainable alternative to radar-absorbing materials. (April 2020)

• Record Type: Journal Article
• Authors: Boss, Alan FN; Braghiroli, Flavia L; Amaral-Labat, Gisele; Souza, Ariane AT; Baldan, Mauricio R; Bouafif, Hassine; Koubaa, Ahmed; Lenz e Silva, Guilherme FB
• Is Part Of: Journal of composite materials. Volume 54:Number 9(2020)
• Page Start: 1233
• Page End: 1244
• Publication Date: 2020-04
• Subjects: Sustainability -- biochar -- radar-absorbing material -- reflectivity -- microwave-absorbing material; Composite materials -- Periodicals; Composites -- Périodiques; 620.118
• DOI: 10.1177/0021998319877493
• Languages: English
• ISSNs: 0021-9983

Abstract

Sustainability can be defined as the ability of meet presents needs without compromise the ability of future generations to find their own needs. In this matter, scientists have been warning about natural resource scarcity, and now several researchers are aiming their efforts to develop sustainable technologies. Here, we focus on finding novel uses to biochar, a carbon rich material made from biomass that is usually applied on soil amendment. To expand its applications, biochars were activated using two different methods: a physical activation using CO2 ; and a chemical one using KOH. We investigate here the dielectric properties of composites made with both activated biochars from white birch, where composites were made using silicone rubber matrix. It was also investigated the influence of composites made with biochar in powder and in flakes. All samples were characterized over the X-band frequency range. Composites made with powder presented a linear permittivity over the frequency range, while composites made with flakes presented oscillations on different frequencies. These oscillations are related to the composite surface, which induces reflection effects because of flakes arrangement in the top surface. Such effects widen opportunities to engineer new materials to be explored as radar-absorbing materials.