Enhancing Optical Properties of Modified PVC and Cr2O3 Nanocomposite

Abstract

In this work, a novel grafting of chromium (III) oxide Cr2O3 nanoparticles (NPs) within polyvinyl chloride (PVC) was conducted to obtain high conductivity and stability toward the light absorption for the polymer. The optical properties of pure and doped PVC thin films were investigated with different content to embed chromium (III) oxide. The measurements of spectrophotometer reflectance in the wavelengths range of 250–1300 nm and UV–Visible in the wavelengths range of 200–800 nm were reported. Adding 0.05 g of Cr2O3 NPs leaded to improve all the optical properties of PVC–Cr2O3 films. The optical features calculations were determined, namely absorbance, reflectance, transmittance, extinction coefficient, refractive index, optical density, real and imaginary of dielectric constant, direct and indirect energy gaps, Urbach energy, and optical conductivity. Two Schiff bases were synthesized and used for doping, identified as a, and b. The energy gaps of modified PVC films were calculated and found to decrease from 5.5 eV of pure PVC to 2.4 and 3.2 eV for a and b samples, respectively, in the direct allowed transition. In the indirect allowed transition, lower values were obtained, where the pure PVC gab was 4.2 eV and decreased to 1.75 and 3.3 eV for a and b, respectively. The Urbach band tail was also computed for thin films and concluded in a table. For our best knowledge, doping Cr2O3 NPs in the PVC is firstly reported here, which aimed to reinforced the polymer and reduced its energy gap. The results detected that the photostability of doped PVC is better than the pure PVC.