Effects of 100Â MeV O7+ ion beam irradiation on the optical, chemical and structural properties of NCO-terminated polybutadiene based liquid crystalline polyurethane

NCO-terminated polybutadiene based liquid crystalline polyurethane films were irradiated with O7+ ion beam at various fluences ranging 3 × 1010 to 1 × 1012 ions/cm2. Significant modifications in the structural, optical and chemical properties have been observed after irradiation. UV-visible spectra show a shift toward the higher wavelength regime after irradiation owing to the decrease in the band gap. FTIR spectra show the formation of NH2 group and CC bonds. The XRD spectra show the semi-crystalline nature of LCPU and with increasing fluence of irradiation a decrease in crystallinity is observed. However an increase in crystallinity at certain fluence followed by a decrease at the higher fluence of irradiation reveals the presence of secondary radiation induced crystallinity in LCPU.