Structural and Optical Investigations of Radiation Damage in Transparent PET Polymer Films

[摘要] Effects of gamma irradiation at different doses up to 135 kGy on polyethylene terephthalate (PET) polymer films have been investigated by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and ultraviolet-visible (UV-VIS) spectroscopy. From XRD analysis, it was found that even at a high dose of gamma irradiation of 135 kGy, crystallinity of the PET samples remain unchanged. However, the FTIR peak at 871 cm−1(depicting C–H bending mode of out-of-plane vibration) andanother at 1303 cm−1(representing C–H bending mode of in-plane vibration) disappear for gamma-irradiated PET. In this study, it has also been found thatγ-irradiation in air enhances the optical absorption in the wavelength region 320–370 nm. This has been attributed to free radicals being produced in the polymer by theγ-radiation. Further, the free radicals react with oxygen of air to form carbonyl group and hydroxyls. With increasingγ-dose, there is a red shift of the UV—near visible cutoff for PET. XRD and FTIR observations onγ-damage have been correlated.

[学科分类] 光谱学