Structural, Morphological, Thermal, Dielectric, and Electrical Properties of Alumina Nanoparticles Filled PVA-PVP Blend Matrix-Based Polymer Nanocomposites

Alumina (Al2O3) nanoparticles filled poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) blend matrix (50/50 wt%) based polymer nanocomposite (PNC) films (i.e., [PVA-PVP]-x wt% Al2O3 ; x = 0, 1, 3, and 5) have been prepared by solution-cast method. X-ray diffraction study has confirmed that the structures of these PNC materials are predominantly amorphous. The formation of miscible blend, polymer-polymer and polymer-nanoparticle interactions, and the effect of Al2O3 nanoparticles on the thermal properties of PVA-PVP blend matrix have been examined by Fourier transform infrared, differential scanning calorimetry and scanning electron microscopy measurements of the PNC films. The dielectric and electrical spectra of these PNC films have been measured from 20 Hz to 1 MHz using dielectric relaxation spectroscopy. It has been found that the dispersion of merely 1 wt% Al2O3 nanoparticles in the PVA-PVP blend matrix significantly reduces the crystalline phase and enhance the melting phase transition temperature of the PNC material, while the dielectric permittivity greatly decrease due to nano confinement effect. The real parts of dielectric permittivity and the impedance of these PNC films decrease linearly with the increase of the frequency, whereas the ac electrical conductivity has increased. A nonlinear increase of dielectric permittivity has been found with an increase of the temperature of PNC film and its dc electrical conductivity obeys the Arrhenius behavior. The dielectric and electrical properties of these PNC materials confirm their suitability as flexible nanodielectric of frequency tunable permittivity. (C) 2018 Society of Plastics Engineers