Functionalization of Polyvinyl pyrrolidone/Polyvinyl alcohol blends doped with zinc sulfate and irradiated with electron beam

Abstract

Abstract Nanocomposite films of poly(vinyl alcohol) (PVA) and poly(vinylpyrrolidone) (PVP) doped with Zn2+ ions are prepared using in situ chemical method. The as-prepared samples are irradiated with an electron beam at doses of 20, 25, 30, 35, and 40 kGy. As demonstrated by the measured X-ray diffraction spectra, the films exhibited a polycrystalline nature with substantial enhancement of crystallinity from 6.2% to 27.5% with increasing irradiation dose. This finding is indicative of enhanced polymer chain ordering. Field emission scanning electron microscopy revealed uniform dispersion of Zn2+ nanoparticles accompanied by an increase in particle size from 3.58 to 4.25 μm against applied radiation doses. The measured infrared spectra demonstrated an interaction between hydroxyl group in PVA and Carbonyl group in PVP accompanied by an increase in the number of free ions with increasing irradiation dose. Thermal spectrum measurements conducted using differential thermal analysis and thermogravimetric techniques demonstrated an enhancement in chemical stability as evidenced by an increase in glass transition temperature from 33.2 °C to 35.6 °C. Kinetic spectrum analysis using Coats–Redfern method revealed an increase in activation energy, enthalpy, and Gibbs free energy against irradiation dose. The impedance and dielectric measurements exhibited non-Debye relaxation, with Nyquist plots showing reduced semicircle diameters at elevated temperatures. The highest dielectric constant was observed at a dose of 40 kGy. This find establishes a correlation between irradiation induced crystallinity and nanoparticle polymer interaction and demonstrated an enhancement in electrical performance.