Insights into dielectric and thermal properties of polystyrene-zinc oxide nanocomposites: A multifaceted characterization approach

In this study, zinc oxide nanoparticles (ZnO) were successfully incorporated into polystyrene (PS) using a combination of solution mixing and hot-pressing methods, yielding a range of PS/ZnO nanocomposites. Characterization using X-ray diffraction (XRD) techniques, scanning electron microscopy (SEM), impedance spectroscopy (IS), Raman spectroscopy (RS), thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) revealed distinct features. XRD analysis of nanocomposites showed both weak and high-intensity peaks at different scattering angles (2θ = 8°–11° and 20°–22°), indicating amorphous phases PS phases with varying sizes of nanoparticles. It has been proved that the addition of higher amounts of ZnO leads to the disappearance of the maximum of weak intensity in the studied substance (PS/10%ZnO), which is due to the formation of microcrystalline regions that lead to the formation of sharp maxima with high intensity. It was determined that the increase in the concentration of ZnO up tp 5 % volume content enhances the dielectric permeability (ε) and polarization capacity of polystyrene. It is believed that, depending on the ZnO concentration, the increased dielectric permeability and polarizability are attributed to phases with different charge densities at the boundaries between the ZnO nanoparticles and the matrix, which promotes additional polarization and contributes to the overall enhanced permittivity. This formation of interfacial boundaries is evident from the stepwise shape of the thermogravimetric (TG) curve with increasing ZnO content. The introduction of ZnO nanoparticles into PS results in the formation of new phases, altering the intensity and position of peaks observed at frequencies of 376 cm⁻1 and 485 cm⁻1 in the Raman scattering spectrum, partially shifting towards higher frequencies.