Toward Biodegradable Materials via Titanate-Catalysed Green Ring-Opening Polymerization of Cyclic Esters at Ambient Temperature

摘要

We report the synthesis of biodegradable polyesters through titanate-catalyzed ring-opening polymerization (ROP) at mild temperature. Four-arm star-shaped aliphatic polyesters poly(ε-caprolactone) (PCL) have been successfully synthesized via a new strategy that uses titanates with isopropyl, butyl, propargyl, allyl as initiator to mediate controlled ROP of ε -caprolactone (CL) at ambient temperature of 25-40°C under the normal atmosphere. The titanate-catalyzed ROPs of CL are much faster than the stannous octanoate-catalyzed ROP under the same reaction condition. The resulting polymers can be used as macroinitiators for chain extension polymerization of CL or block copolymerization of lactides. Click chemistry can be applied to conjugate propargyl end-capped poly(ε-caprolactone) and azido-containing molecules, resulting in bioactive or fluorescent PCL.