Development of porous and electrically conductive activated carbon web for effective EMI shielding applications

In present work, porous and electrically conductive activated carbon needle punched nonwoven web was produced by heating acrylic fibrous wastes under the layer of charcoal using novel single stage carbonization and physical activation. The influence of 800 °C, 1000 °C and 1200 °C carbonization temperature on physical and morphological properties of activated carbon web was studied from EDX, X-ray diffraction, SEM, X-ray tomography and BET analysis. Additionally, the electrical conductivity was also measured. At the end, the utility of prepared activated carbon web was investigated for electromagnetic shielding ability in high frequency (i.e. at 2.45 GHz) and low frequency regions (i.e. below 1.5 GHz) using waveguide method and coaxial transmission line method, respectively. The activated carbon web produced at 1200 °C showed maximum shielding effectiveness in both high and low frequency regions. For single layers of 1200 °C web, the electromagnetic shielding effectiveness of 63.26 dB, 66.75 dB, and 75.44 dB was found for respective frequencies of 600 MHz, 1 GHz, and 1.5 GHz. This behavior was attributed to the increased multiple internal reflections and stronger absorption of electromagnetic radiations in 1200 °C activated carbon web.