The FTIR spectra (Attenuated Total Reflectance mode) were recorded using a Perkin Elmer Spectrum (Akron, OH, USA) 100 with 16 scans per sample. The differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were performed simultaneously by TGA-DSC Discovery of TA Instrument (New Castle, DE, USA). TGA was recorded for 50–500 °C at 10 °C/min under air atmosphere, while the DSC was run for 150–550 °C at 10 °C/min under nitrogen atmosphere, but the crucible lid was pierced seven times, allowing the gas to escape. SEM images were registered at high vacuum for secondary electrons with acceleration voltage of 1–5 kV, recorded by field-emission equipment JEOL JSM-7600F (Tokyo, Japan). The sample was dispersed by ultrasound bath in isopropyl alcohol.