Efficient Synthesis of Itaconate Polyesters with Amine-Triggered Rapid Degradation and Outstanding Mechanical Properties: An Experimental and Theoretical Study on Degradation Mechanisms

A range of degradable polyesters have been developed as sustainable alternatives for commercial plastics; however, limitations of composting facilities and uncontrolled degradation in the environment hindered their viability. In this study, biobased itaconic acid was selected as an active site to control the degradation of polyesters. A series of PBXI copolyesters with Mw's ranging from 4.86 to 8.31 × 104 g/mol and high intrinsic viscosities of more than 1.15 dL/g were successfully synthesized without any cross-linking by selecting appropriate reaction conditions, including condensation temperature and vacuum, effective inhibitor, and catalyst. The obtained copolyesters were semicrystalline, and their Tm's could be regulated from 42.5 to 179.5 °C. They exhibited outstanding elastic modulus (120–598 MPa) and tensile strength (17.9–51.4 MPa) among degradable polymers. Degradation experiments demonstrated that the incorporation of itaconate segments could facilitate both the hydrolysis and enzymatic degradation of polyesters. The state-of-the-art computation and analysis via molecular dynamics (MD) simulations of PBXI–CALB complexes elucidated the enzymatic degradation mechanism. Experimental results proved that, at room temperature, the degradation could be stimulated and regulated by amines without a catalyst and the Mn's of lactamization products rapidly decreased to less than 5000 g/mol within 24 h. Moreover, the copolymerized structure of copolyesters and solvent factors could influence the aza-Michael addition between amines and itaconate units. This work provides a strategy to synthesize biodegradable copolymers with the potential to undergo controlled and rapid in vivo degradation with outstanding mechanical properties.