Self-healing polyester elastomer with tuning toughness and elasticity through intermolecular quadruple hydrogen bonding

It is a desirable to prepare high performance polyester elastomers that possess high strength, good elasticity and efficient self-healing capability. Herein, we report the preparation of such elastomers based on aliphatic polyesters cross-linked by UPy-UPy quadruple hydrogen bonding. A functional monomer α-methylene-γ-butyrolactone (MBL) was copolymerized with ε-caprolactone (ε-CL) to give pendent double bonds functionalized copolyester precursors, which were subject to post-modification with UPy groups via the efficient thiol-ene click reaction. Then, the self-healing polyester elastomers were finally obtained by tuning the molecular weight of precursors, the contents of UPy units and crystallization behaviors. The results show that high polyester molecular weight, moderate UPy content and inhibition of crystallization are helpful to improve the mechanical and self-healing properties of elastomers. The obtained elastomers show good mechanical strength (1.0–1.5 MPa), excellent elongation at break (970–1560 %) and toughness (9.6–11.9 MJ/m3), and have the rapid self-healing property (>70 % after healing at 60 °C for 2 h), displaying great potential in biomedical applications.