Synthesis and microwave absorption studies on 2D graphitic carbon nitride loaded polyaniline/polyvinyl alcohol nanocomposites

Abstract

A light weight electromagnetic interference (EMI) shielding and microwave absorbing composite films has been developed by loading varying weight content of graphitic carbon nitride (g-C₃N₄) nanosheets and polyaniline (PANI) into polyvinyl alcohol (PVA) matrix. The prepared PVA/PANI/g-C₃N₄ (1%, 3%, 5%) composites has been subjected to FTIR, X-Ray powder diffraction, SEM, Thermal studies, Dielectric studies and electromagnetic shielding effectiveness (EMI SE) analysis. The PVA/PANI/g-C₃N₄ (1%, 3%, 5%) composites was discovered to have improved electrical conductivity, dielectric loss, and dielectric constant. It is observed from the SEM images that the sheet layers of g-C₃N₄ are wrapped by the polymer matrix and the morphology to PVA/PANI composite in the g-C₃N₄ indicates homogeneous blending of PVA/PANI without any phase separation and has porous in it. The PANI/g-C₃N₄ fractured surfaces present are smooth but irregular in appearance indicating good compatibility between the PVA and PANI matrices. The dielectric properties was found to increase on increasing the concentration of the g-C₃N₄ nanofiller and reached a maximum of 9.8 × 10⁶ at 1 MHz for 3% g-C₃N₄ in PVA/PANI. The incorporation of g-C3N4 into PVA/PANI enhanced the conductivity and the 5% g-C₃N₄ loaded composite film exhibited a conductivity value of 0.043 S/cm at 1 MHz. The PVA/PANI/g-C₃N₄ (1%, 3%, 5%) composites exhibited potential EMI SE values ranging from 24 to 35 dB at 8.6 GHz and from 42 to 63 dB at 12.4 GHz, for instance the PVA/PANI/g-C₃N₄ 5% composite showed highest value of 63 dB at 12.4 GHz. The PVA/PANI/g-C₃N₄ 5% exhibits the maximum highest reflection loss 8 GHz–12 GHz in which the higher absorption of −36 dB is observed at 10.3 GHz of the X-band region.