Physical and chemical response of 145Â MeV Ne6+ ion irradiated polymethylmethacrylate (PMMA) polymer

Characterization of ion induced modifications in the physical, chemical and structural properties of polymethylmethacrylate (PMMA) polymer induced by 145 MeV Ne6+ ions has been carried out by FTIR, UV-Visible, Differential scanning calorimetry (DSC) and X-ray diffraction. Heavy ion irradiation was carried out under a vacuum of ∼10−6 torr at Variable Energy Cyclotron Centre, Kolkata, India using a low beam current (∼15 nA). Ion fluences of 1010, 1011, 1012, 1013 ions/cm2 were used. The optical band gap (Eg), calculated from the absorption edge of the UV-Vis spectra of these films in 200-800 nm region varied from 2.167 eV to 1.512 eV for virgin and irradiated samples. In FTIR spectra appreciable changes have been observed after irradiation, indicating the molecular fragmentation, cross-linking, formation of unsaturated groups and free radicals. DSC thermograms give information about the thermal stability and type of thermal reactions (exothermic/endothermic) on the application of heat to the polymer. XRD analyses show slight shift of peak position and significant changes in peak intensity. XRD results show a decrease of ∼4.12% in crystallite size of irradiated sample at the higher fluence of 1012 ions/cm2.