▎ 摘　　要

In this work, polymer nanocomposite (PNC) samples based on a host matrix of polyvinyl alcohol/carboxymethyl cellulose (PVA/CMC) blend and two nanofillers (graphene nanoplatelets GNP and titanium oxide nanoparticle TiO2 NPs) have been prepared by the solution casting procedure. The TEM and XRD techniques micrographs indicate the platelet shape of GNP with nanosheet dimension, the anatase phase of the cubic/tetragonal TiO2 NPs with a crystalline size range 7-42 nm and their dispersion in the crystalline regions of the host matrix. FTIR absorption spectra reveal the miscibility between PVA and CMC and their interaction/complexation with GNP/TiO2 NPs. The TGA data depicts that the addition of GNP/TiO2 NPs extremely improves the thermal stability/charring of the PVA/CMC blend. The optical bandgap value is decreased from 4.02 to 1.88 eV for the nanocomposite sample (GNP/6 wt% TiO2 NPs), and the absorption edge gradually moves towards longer wavelengths upon the addition of GNP/TiO2 NPs. The electrical conductivity and dielectric properties of the PVA/CMC-GNP/TiO2 NPs films are significantly enhanced over the frequency range 0.1 Hz to 10 MHz. Further, the dielectric parameters and electric modulus of these PNC films have been investigated, where the GNP/TiO2 NPs successfully enhance the host matrix's capacity for energy storage. The stress-strain behavior of PNC samples is tested, where the tensile modulus and elongation at break are significantly improved. Thus, the fascinating physicochemical properties evidence the favorable applications of these biodegradable PNC films in the fabrication of flexible-type micro-and optoelectronic techniques as nanodielectric substrate, light diffuser, bandgap regulator, photosensor, UV-shielder and food packing uses.