Facile synthesis and characterization of polymer composites with cobalt ferrite and biomass based activated carbon for microwave absorption

Abstract

In this work, flexible EMI shield materials have been prepared by the solution cast technique using AC-STG {activated carbon derived from Sal tree's gum}, CoFe2O4 nanoparticles and a polymer electrolyte {P(VDF-TrFE) + 15 wt% LiTFSI + 50 wt% EMIMTFSI}. The prepared polymer composites have been characterized for structural, morphological, thermal, ionic conductivity, dielectric, and magnetic properties. EMI shielding effectiveness has been obtained in the X-band (8.2–12.4 GHz). AC-STG particles have been characterized using XRD, FESEM EDX with elemental mapping, FTIR and RAMAN techniques. The CoFe2O4 (CF) nanoparticles have been prepared using the hydrothermal method. The highest ionic conductivity of ∼ 3.24х10−3 S.cm−1 for polymer electrolyte (PE15IL50) has been obtained at room temperature. On addition of AC-STG and CF particles to the polymer electrolyte, enhanced EMI shielding effectiveness and thermal stability of the composite films has been achieved. Also, FTIR results give the confirmation of interaction between the polymer electrolyte, AC-STG and CF particles. This study demonstrates that the EMI shielding properties of the polymer composite (PE15IL50AC-STG4CF5) get improved owing to the synergy between the properties of AC-STG and CF nanoparticles resulting in EMI shielding of ∼ 49.6 dB at 8.2 GHz (absorption ∼ 99.99%). There are three factors, viz., dielectric losses, magnetic losses and interfacial polarization which contribute majorly to this much desirable EMI performance. The studies being reported indicate PE15IL50AC-STG4CF5 polymer composite to be an excellent biomass-based composite for EM wave absorption.