Fabrication and characterization of PVA-based biocomposite EMI shielding material for low power loss wireless charging applications

Emission of radio waves or electromagnetic waves is increasing in recent days due to emerging people to people connection and internet, mobile network connection. To reduce such electromagnetic interference (EMI), the shielding is used in those EMI caused equipment. The present study fabricated flexible polyvinyl alcohol (PVA) composites reinforced with rice husk microfiber, dragon fruit peel biochar, and cobalt nanoparticles which makes a novelty to this study. The composites were produced using the stir casting method, and test specimens were characterized according to ASTM standards. Among the composite designations, PF23 exhibited superior mechanical properties, including a tensile strength of 73 MPa and a low elongation of 142%, accompanied by a Shore-D hardness of 40. The incorporation of biochar and cobalt filler particles with rice husk microfiber significantly enhanced the mechanical properties of the matrix. Furthermore, the dielectric properties of PF23 demonstrated improvement, with dielectric permittivity values of 5.48, 4.1, 2.21, and 0.98 for frequency bands of 8 GHz, 12 GHz, 16 GHz, and 20 GHz, respectively. Similarly, PF23 exhibited enhanced magnetic permeability values of 3.42, 3.94, 4.43, and 5.99 for the same frequency bands. Moreover, PF23 demonstrated superior electromagnetic interference (EMI) shielding effectiveness, with total shielding values of 7.41 dB, 10.92d B, 16.45 dB, and 22.79 dB for frequency bands ranging from 8 to 20 GHz. Overall, the incorporation of rice husk microfiber, dragon fruit peel biochar, and cobalt nanoparticles resulted in multifunctional PVA composites with improved mechanical, dielectric, magnetic, and EMI shielding properties, making them promising candidates for various applications in electromagnetic shielding and related fields.