Development and characterization of biocomposites using highly porous cellulose and pearl millet Cob microfiber for EMI shielding application

The primary aim of this research is to create bio-based electromagnetic interface (EMI) materials from pearl millet cob microfiber and plant stalk derived highly porous cellulose for EMI shielding applications. Because of its superior mechanical and thermal qualities, biocompatibility, and biodegradability, cellulose is attracting a lot of interest in the development of EMI shielding materials. Further, the prepared reinforcing materials underwent silane treatment with 3-aminopropylmethoxysilane, and the composites were fabricated using manual layup technique. The prepared composites were further tested as per American Society for Testing and Materials (ASTM) standards. Further, results showed that the EMI shielding efficacy increased due to the incorporation of cellulose filler. The composite ENC2 with 4 vol.% high porous cellulosic content offers superior EMI shielding efficiency of 2.7 dB at 2 GHz to 3.9 dB at 8 GHz of absorption, 2.3 dB at 2 GHz to 4.7 dB at 8 GHz of reflection and 2.5 dB at 2 GHz to 3.7 dB at 8 GHz of total EMI shielding. Additionally, the composite ENC2 exhibits dielectric characteristics ranging from 2.8 at 2 GHz to 1.2 at 8 GHz, with a dielectric loss of 0.14 at 2 GHz to 0.21 at 8 GHz, and maximum total EMI shielding of 2.5 dB at 2 GHz to 3.7 dB at 8 GHz. Conversely, at a burning rate of 8.97 mm/min, the composite ENC2 with 4 vol.% filler exhibits good flame-retardant properties. On the other hand, the composite ENC1 with a 2 vol. % cellulose incorporation had the highest mechanical performance, with tensile and flexural strengths of 136.8 MPa and 158 MPa, respectively. Therefore, this EMI shielding effectiveness, dielectric properties, flame-retardant, and mechanical strength make the composites to be widely employed in communication and navigational device, sensor, and EMI shielding products.