Studies of chemical bonds loss and optical modifications of CR-39 caused by gamma rays

Abstract

The induced impacts of high doses of gamma irradiation on the structural variations of poly-allyl-diglycol carbonate (PADC) polymers (CR-39) were studied in terms of X-ray diffraction (XRD) patterns. CR-39 samples were irradiated separately at different ranging from 200 to 800 kGy; (step 200). A deconvolution process of the XRD spectra of CR-39 samples for all gamma irradiation doses was performed. The results of this deconvolution process for the pristine specimen show three diffraction peaks at about 20.30°, 28.16° and 41.70° of 2θ. The broad peaks at 28.16o and 41.70°, and the highest peak at 20.30° of XRD confirm the amorphous nature and low degrees of crystallinity, respectively. The position, area, intensity and full width at half maximum of these peaks are changed with further doses of gamma irradiation. With additional gamma irradiations, the intensities of all peaks decrease significantly. The highest and sharpest peak properties are employed to determine the crystallinity, crystallite size, and radiation chemical yield (G-value) for the loss of carbonate ester bonds using a proposed method. Higher doses of gamma irradiation result in a decrease in crystallinity while increasing crystallite size. Furthermore, the optical band gaps reduced from 4.81 to 3.49 eV when the irradiated dose increased from 0 to 800 kGy. Furthermore, the third order nonlinear susceptibility increased from 0.84x10−12 esu to 2.25x10−12 esu with increasing the radiation doses from 0 to 800 kGy. Moreover, the nonlinear refractive increased from 1.52x10−11 to 3.69x10−11 with increasing the radiation doses from 0 to 800 kGy. On the other hand, the number of carbon atoms in each cluster increased from 51 to 97 when the irradiated dose increased from 0 kGy to 800 kGy.