Synthesis of Oxetane-Functional Aliphatic Polyesters via Enzymatic Polycondensation

Synthesis, characterization, and thermal properties of a series of oxetane-functional aliphatic polyesters are investigated. The incorporation of the acid-sensitive 3,3-bis(hydroxymethyl)oxetane (BHMO) into polymers is achieved by using the enzyme CALB (Candida antarctica Lipase B) as a catalyst. This mild synthetic strategy provides well-defined, oxetane-functional polyesters. The enzymatic polycondensation allows for the synthesis of a series of aliphatic polyesters containing various ratios of the difunctional monomers sebacic acid, 1,8-octanediol, and BHMO with molecular weights between 50009800 g mol-1 and polydispersity indices (Mw/Mn) in the range of 1.25 and 1.92. Furthermore, crosslinking of BHMO and a polymer sample is carried out via opening of the pending oxetanes.