UV-visible spectroscopic investigations on the post-irradiation storage effect of polystyrene

Abstract

Polystyrene is an electron-rich polymer wherein the electrons ejected on irradiation are localized and could be investigated by using spectroscopic methods. Pre-irradiated, PTPC (Pre-irradiated Tarsons Polystyrene Control) were irradiated with a cumulative dose of γ-rays 51, 77 and 129 kGy at 300-308 K referred to as RTPS (Re-irradiated Tarsons Polystyrene Samples). These RTPS were subjected to different post-irradiation treatments and were analyzed by UV-Vis absorption spectrometry. The regions 300 – 400 and 600 – 900 nm show differential absorption in RTPS in dose dose-dependent manner. The energy is absorbed by the phenyl chromophores of PS and redistributes the excitation energy. The data clearly suggests that RTPS (1mm) has retained its structural and chemical integrity as evidenced by UV-Vis spectrometry and hydrogen ion concentrations. The sterility was maintained for prolonged periods until packed properly facilitating the re-use multiple times before discarding. Though γ-irradiation has been in use for sterilization for a long time. The applications include the reusability of PS materials and evidence is provided for the structural and chemical integrity after re-irradiation. This method is cost-effective for biological laboratories and environmentally friendly.