**3.5 Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR)**

FTIR is a sensible method for identifying chemical modification in a material and, so, is capable to detect chemical modifications in a polymeric material. This method detects vibrational movements imparted from chemical bonds for the material that is being analyzed. As each chemical group absorbs vibrational energy at a given value, it is possible to differentiate them via infrared spectrum. Spectra were obtained from a PerkinElmer, universal ATR sampling accessory spectrum 100 FTIR spectrometer. Setup collection sample was adjusted for 64 scans, within a 4000–650 cm<sup>−</sup><sup>1</sup> range.
