2.4. Fourier transformation infrared spectroscopy with Attenuated Total Reflection FTIR-ATR analysis FTIR-ATR spectroscopy (Perkin Elmer Spectrophotometer Spectrum 100, Waltham, MA, USA) was used to analyze the fillers as well as the polymeric films. The averages from 16 measurements of FTIR-spectra were taken in a wavenumber range of 4000 -550 cm -1 and processed using Omnic software.