Influence of Gamma Radiation on Optical and Morphology Properties for PS and MO/PS Composites

Abstract

In this work, the effect of gamma irradiation on optical characteristics of virgin polystyrene (PS) and its composite films was examined. The neat PS and its composites casted to be thin-films both before and after being doped with methyl orange (MO) at weight ratios of 1.0 % wt. /wt. Thickness of the obtained samples varied within the range of 0.2±0.05 mm. The prepared samples were exposed to 1.0, 5.0, and 10 kGy of 60Co (a gamma source) radiation. The optical properties were investigated using ultraviolet-visible spectra within a wavelength range of (280-1100 nm). The samples' absorption spectra were displayed both before and after irradiation. For PS and MO/PS nanocomposites, gamma radiation caused systematic changes in absorption with absorbed doses. The optical bandgap for PS decreased after adding methyl orange dye, and when the gamma ray dose increased from 1.0 to 10 kGy, the direct bandgap decreased from 4.24 to 3.90 eV for PS, and decreased from 4.13 to 3.4 eV for MO/PS. The abovementioned outcome demonstrated by the redshift in the transmittance spectra using Fourier Transform Infrared Spectroscopy (FTIR). The effects of γ-rays on the absorbance, absorption coefficient (α), and extinction coefficient (k) into all the samples were studied, and the findings showed an improvement in parallel with increasing radiation dose. The optical microscope images showed surface damage represented grooves, holes, bubbles, and cracks caused by samples photo-degradation. It was concluded that gamma rays could alter different characteristics of materials in terms of making them suitable for radiation detection, sensing, and dosimetry.