Features of structure and optical properties GO and a GO/PVA composite subjected to gamma irradiation

Abstract

In this study, a modified Hummers' method was employed to prepare graphene oxide (GO), which was then mixed with polyvinyl alcohol (PVA) polymer at varying weight concentrations (1 wt% and 5 wt%). The prepared GO and GO/PVA nanocomposite films were subjected to gamma (γ) radiation at different doses (10, 500, and 1500 kGy) to analyze the effects on their structure and optical properties. The structural changes in the nanocomposites were analyzed using X-ray diffraction (XRD), allowing for the determination of any alterations resulting from exposure to radiation at different doses. Furthermore, elemental analysis was conducted using an energy-dispersive spectrometer (EDS) to gain insights into the elemental composition of the samples. The optical properties of the samples were investigated using ultraviolet-visible (UV-Vis), Fourier-transform infrared (FTIR), Raman spectroscopy, and scanning electron microscopy (SEM). These analysis methods provided valuable information regarding any changes induced by gamma radiation. Notably, in the study, the decomposition and oxidation of residual graphite were observed under the influence of γ radiation. One noteworthy finding was the decrease in the band gap value of the samples with increasing gamma radiation. This observation indicates that the radiation exposure influenced the electronic properties of the nanocomposites, leading to changes in their optical behavior. The Raman spectra clearly showed that the strength of the G and D bands dropped at low doses and reached a maximum at higher doses. FTIR intensity varies with radiation, indicating the separation of oxygenated groups during exposure. The SEM images revealed that as the radiation dose increases, the disintegration of GO on the polymer's surface happens, and at the greatest dose, the distribution of GO and PVA in the pores occurs due to the heating action of radiation.