Lipase-catalyzed synthesis of acid-degradable poly(β-thioether ester) and poly(β-thioether ester-co-lactone) copolymers

A novel linear polyester with acid-labile β -thiopropionate groups was synthesized via the direct lipase-catalyzed polycondensation of methyl 3-((2-hydroxyethyl)thio)propanoate (MHETP) using immobilized lipase B from Candida antarctica (CALB). The influences of reaction conditions such as polymerization temperature and time on the molecular weight of the poly( β -thioether ester) (PTE) were studied. Ring-opening and condensation copolymerization of MHETP with ε -caprolactone (CL) led to the synthesis of novel poly( β -thioether ester- co - ε -caprolactone) copolymers , poly(TE- co -CL), with well-defined composition and narrow polydispersity . The random copolymers were characterized by 1 H NMR, 13 C NMR, 2D NMR , GPC , TGA and DSC . The degradation of the poly( β -thioether ester) under acidic conditions was investigated by GPC and 1 H NMR spectroscopy.