Biomass-Derived Activated Carbon/Epoxy Composite as Microwave Absorbing Material

An activated carbon/epoxy composite was synthesized in which waste mango leaves biomass was used as the carbon source. To create a sufficient amount of porosity in the biomass, a simple process of carbonization followed by its activation was used. The morphology and porosity of the activated carbon material were studied by SEM, TEM, and BET analysis, which confirmed the presence of macro- and mesopores in the material. The activated carbon/epoxy composite with 3 mm thickness gave the highest reflection loss (RL) of - 39.57 dB at 6.48 GHz. At a thickness of just 2 mm the maximum effective absorption bandwidth (RL < -10 dB) of 2.14 GHz was achieved. This excellent microwave absorption performance was attributed to the porous and bowl-type structure, which resulted in large surface area, high impedance matching, and subsequent attenuation of microwaves by conduction losses, as well as interfacial and dipolar polarization processes. This study provides a porous activated carbon/epoxy composite that is lightweight and economical, and has a high structural stability for microwave absorption applications. [GRAPHICS] .