Modifications of structural, optical and chemical properties of Li3+ irradiated polyurethane and polyetheretherketone

• We irradiated PU and PEEK with swift heavy ions at different fluences.
• Structural effects, optical and chemical changes after irradiation were examined by XRD, UV–visible and FTIR spectroscopy, respectively.
• Decrease in amorphous nature and band gap energy is observed with increase in fluence.
• Increase in average crystallite size and variation in Urback's energy is observed with increase of fluence.
• The modifications caused by SHI in various chemical bonds are also discussed.

Thin membranes of PU and PEEK polymers were irradiated with 50 MeV lithium ions for modifications in structural, optical and chemical properties. The XRD spectra indicated the alignment of polymeric chains in a regular pattern and hence there was decrease in the amorphous character of the irradiated polymers. The optical absorption of all irradiated samples shifted towards the visible region of the spectrum. It was attributed to the generation of a conjugated system of bonds which lowered the band gap energy of irradiated samples. The FTIR spectra obtained after irradiation exhibited decrease in absorbance for various bands in case of PU whereas PEEK showed minor changes in its chemical properties. The other results were discussed from the calculated parameters such as crystallite size, Urbach's energy and number of carbon hexagon rings per conjugation length from the analyses of the XRD and UV–visible data.