Structural, dielectric and EMI shielding properties of polyvinyl alcohol/chitosan blend nanocomposites integrated with graphite oxide and nickel oxide nanofillers

Polyvinyl alcohol (PVA) and Chitosan (CS)-based novel composites were prepared using solution casting technique by introducing graphite oxide (GO) and nickel oxide (NiO) as nanofillers. The structural, thermal and mechanical properties of PVA/CS/GO/NiO nanocomposites were investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analyzer (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The dielectric and electromagnetic interference (EMI) shielding properties of synthesized nanocomposites were also investigated. The addition of dual nanofillers in the PVA/CS blend resulted in improved thermal stability of nanocomposites through the interaction of nanofillers with OH groups of polymer matrices. The DMA results displayed higher storage and loss modulus at low temperature for nanocomposite with 1.5/15 wt% of GO/NiO loading. The maximum values of dielectric constant and dielectric loss obtained are 1315.5 and 11.1 at the low-frequency region, respectively. The absorption dominated EMI shielding effectiveness (SE) was observed with a maximum EMI SE value of 12 dB for nanocomposite film containing 3.0/30 wt% of GO/NiO as compared to EMI SE value of 0.3 dB for PVA/CS blend in Ku-band (12–18 GHz) region. The electrical network formation by GO and NiO in the polymer matrix resulted in an improved EMI SE which further emphasizes the potential use of these nanocomposite films as an effective EMI shielding material.