High dose gamma radiation exposure upon Kapton-H polymer for modifications of optical, free volume, structural and chemical properties

Abstract

The radiation treatment of polymeric materials at higher doses followed by analyses of their structural, optical and surface properties probes/scrutinizes their reliability for applications at various platforms. Kapton H is one of the imperative and indispensable polymers used for thermal shielding because of its features of large flammability and high temperature radiation resistance. Furthermore, the insulation of cables, lower de- gassing and nuclear power plant- electrical instruments are a few other applications of this crucial material. The irradiation of this polymer to exalted gamma dose increases its aptness in copious fields by remodelling (shaping) certain attributes. The present study includes the exposure of 30 μm thick samples of Kapton H at different doses of gamma radiation exposure ranging from 100 kGy to 1200 kGy. The free volume was observed to be modified in positron annihilation lifetime spectroscopy experiments. The X- ray diffraction (XRD) studies revealed increased amorphization and hence modified particle size. The UV- visible (UV-vis) spectroscopy showed displacement in the absorption peak in the direction of longer wavelength regime thereby decreasing the band gap energy as per Tauc’s relation calculations. In addition to these results, Fourier transform infrared (FTIR) spectroscopy and photoluminescence studies were also carried out.