Enzymatic synthesis of poly(erythritol sebacate)

This study details the synthesis of poly(erythritol sebacate) (PES), a polyester synthesized via thermal/enzymatic polycondensation of erythritol and sebacic acid in a three-step process. In the first step, a 1:1 molar ratio erythritol and sebacic acid was used, at various temperatures until achieving a theoretical 40% degree of esterification. The second prepolymerization step utilized Candida antarctica lipase B under different conditions. This was followed by a curing step at 150°C for 24 hours. The results indicated that a temperature of 150°C yielded a more homogeneous prepolymer richer in linear ester oligomers, making it the selected condition for the first prepolymerization step. Afterwards, the second prepolymerization yielded prepolymers with varying degrees of esterification and molecular mass distributions, confirming the high selectivity of lipase B for primary hydroxyl groups. These differences in prepolymers influenced the mechanical properties of the resulting polymers after the curing process. Notably, the enzymatic synthesis at 90°C for 48 hours resulted in a prepolymer with a higher degree of esterification (68%) and longer linear chains, producing the polymer with the best mechanical performance. These findings suggest that enzymatic polymerization, under optimal conditions, can yield PES with properties suitable for a wide range of applications.