Construction and self-healing properties of thermoplastic polyimide based on dynamic covalent bonding

Mechanical damage to the surface of polyimide during manufacture and utilization may act as critical determinants of the properties and longevity of the material. In order to address this issue, this study prepared thermoplastic polyimide (TPI) films through the copolymerization of isocyanate and acid anhydride, which possesses superior self-healing ability after being mechanical damaged. Moreover, polyimide films still retain its exceptional tensile strength (>90 MPa) with Young's modulus (E) (>3 GPa), high thermal stability (glass transition temperature (Tg) >220 degrees C), and excellent insulation performance (breakdown strength (Eb) >180 kV/mm) after self-healing. Introducing cross-linked structures and flexible groups into the thermoplastic resin matrix appropriately not only imparts self-healing capabilities to the material but also retains its excellent mechanical properties. The combination of straightforward copolymerization and distinctive self-healing prowess renders it an appropriate strategy for confronting self-healing challenges.