*2.7. Fourier Transform Infrared Spectroscopy (FTIR) Study*

Changes in the chemical structure of samples after being exposed to UV were measured by a Fourier transform infrared spectrophotometer (Thermo, Nocolet 8700, Waltham, MA, USA). The test was conducted according to the KBr pellets method and in the wavelength range of 4000–400 cm−<sup>1</sup> .
