To assess the chemical structure of prepared blends, characteristic bands were recorded with ATR-FTIR spectrophotometer (Figure ). PBS and PBS-DLS blends with Ecoflex revealed the increased intensity of the band characteristic for the presence of methylene groups (-CH2-) in the 2945 -2922 cm -1 range and the carbonyl moiety (C=O) in the 1712-1713 cm -1 . Subsequently, the bands at 1100-1200 cm -1 characteristic for the ester moiety (C-O) were observed along with the band at 600-700 cm -1 typical for alkyl moiety (C-H). The intense band at 1504 cm -1 has been observed, which is characteristic for stretching peaks of the C=C phenylene group. It is assumed that phthalate units present in PBAT were incorporated into PBS/PBAT blend. Moreover, by analyzing the ATR-FTIR spectra of PBS-DLS/PBAT blend, it can be seen that there are no chemical interactions between the copolymer and PBAT since no compatibilizer was used for the preparation of the blend.