Study of high energy (MeV) N6+ ion and gamma radiation induced modifications in low density polyethylene (LDPE) polymer

The optical and structural response of low density polyethylene (LDPE) under the influence of 80 MeV N6+ ion at various fluences (5 × 1011 to 1 × 1013 ions/cm2) and gamma rays at doses 100 and 1000 kGy were studied using UV–Vis spectroscopy and X-ray diffraction (XRD). The optical absorption spectra of N6+ ion irradiated LDPE showed a shift in the absorption edge towards higher wavelength side, which indicated a significant decrease in the direct and indirect band gaps of the films. The optical data showed decrease in the calculated band gap with increasing gamma dose. The diffraction pattern of pristine sample showed the semi crystalline nature of the polymer. The decrease in peak intensity and hence increase in amorphous nature was observed in N6+ ion irradiated samples. The opposite behavior is seen in case of gamma ray exposed samples at 100 kGy dose. The crystallite size (L) decreased but the other factors like interchain separation (R), interplanar distance (d), micro strain (ε), dislocation density (δ) and distortion parameters (g) increased for N6+ ion irradiated samples.