Development, thermal and dielectric investigations of PVDF-Y2O3 polymer nanocomposite films

Abstract

This work involves preparing PVDF-Y2O3 polymer nanocomposites to improve thermal and dielectric properties. X-ray diffraction, SEM, FTIR, TGA and dielectric measurements were applied for these films. The cubic crystal structure of Y2O3 appeared in XRD spectra and the average size was 39 nm. The sample with a concentration of 1.0 wt% achieved the highest intensity of the β-phase peak at 20.2°. The surface images of these samples were of high homogeneity as recorded by SEM microscopy. FTIR analysis showed absorption bands correlated with α, β and γ-phase. The percentage in β-phase in the nanocomposite films improved with an increase in the Y2O3 ratio from 1.0 to 3.0 wt%, especially at 1.0 wt%. From TGA analyzes, it was confirmed that the thermal stability improved with an increase in the yttrium oxide percentage. All of the nanocomposite films had higher values ​​of ΔS, ΔH and ΔG than the pure PVDF film. The dielectric permittivity and energy density of the nanocomposite films improved, especially at 1.0 wt%. The energy density at 0.1 Hz has the values​​ 1.08 x 10-3, 2.11 x 10-3, 1.81 x 10-3 and 1.75 x 10-3 J/m3 at the ratios 0.0, 1.0, 2.0 and 3.0 wt% of Y2O3. The loss tangent values for these nanocomposite films decreased at low frequencies while increased at higher frequencies as the content of Y2O3 increased. A marked improvement in es, e∞, Δe, AC and DC conductivity was observed with an increase in Y2O3 content.