Influence of monomer composition of poly(butylene succinate-co-hexamethylene succinate)s on their enzymatic hydrolysis by Fusarium solani cutinase

Poly(butylene succinate) (PBS), poly(hexamethylene succinate) (PHS) and three kinds of poly(butylene succinate-co-hexamethylene succinate)s (P(BS-co-HS)s) were enzymatically hydrolyzed by Fusarium solani cutinase. The results showed that the characteristics of the enzymatic hydrolysis of these polyesters were mainly affected by crystallinity, thermal properties and the BS/HS ratio. The enzymatic hydrolysis rates of the polyesters are as follows: P(BS-co-HS52) ≈ P(BS-co-HS71) > PHS > P(BS-co-HS32) > PBS. Furthermore, with increasing HS content, both the degree of crystallinity (X_c) and melting temperature (T_m) of the polyesters first decreased and then increased. P(BS-co-HS52) and P(BS-co-HS71) had the lowest X_c and the lowest T_m, thus had the highest hydrolysis rate; this shows that the hydrolysis rate is affected by X_c and T_m. The results also showed that BS/HS ratio could affect the physical properties and degradability of polyesters. Thus, it is possible to prepare polyesters with various physical properties and degradability for different applications by adjusting BS/HS ratio. The crystalline and amorphous regions of the polyesters were both hydrolyzed, during which parts of the crystalline regions were converted into the amorphous regions. Finally, we found that the crystal structure and thermal stability of the polyesters were not affected by the enzymatic hydrolysis.