Correlation between the chemical structure and enzymatic hydrolysis of Poly(butylene succinate), Poly(butylene adipate), and Poly(butylene suberate)

Poly(butylene succinate) (PBS), poly(butylene adipate) (PBA), and poly(butylene suberate) (PBSub) were synthesized and enzymatic hydrolysis was performed in the presence of cutinase. The residues degraded at different times were characterized with respect to their molecular, thermal, crystalline, and chemical structures. The results showed that the degradation behavior of the three polyesters highly depends on their CH2/CO ratio, morphology, and thermal characteristics. The three polyesters were nearly degraded after 24 h, and the degradation rates was in the order of PBSub > PBA > PBS. Gel permeation chromatography and end-group analysis confirmed that the mechanism of enzymatic hydrolysis changed from endo-type to exo-type. The analyses of differential scanning calorimetry, powder X-ray diffraction, and Fourier transform infrared spectroscopy indicated that the cutinase could simultaneously degrade the crystalline and amorphous regions of polyester films. (C) 2018 Elsevier Ltd. All rights reserved.