Rapid Fabrication of Fiber-Reinforced Polyimine Composites with Reprocessability, Repairability, and Recyclability

Polyimine is a type of covalent adaptable networks, known as vitrimer, endowed with dynamic imine bonds that can reversibly break and reform upon either heat or moisture. Its low topology freezing transition temperature (similar to 130 degrees C) and responsiveness to moisture make polyimine suitable for recycling, reprocessing, and repairing under mild processing conditions. Here, we demonstrate the rapid fabrication of carbon fiber-reinforced polyimine composites and their unique properties. Using a powder-based compression molding method, we are able to fabricate carbon fiber-reinforced polyimine within similar to 4 min. The resulting composites exhibit similar mechanical properties as the samples prepared through much slower liquid-based impregnation method (>24 h). We also demonstrate in situ, mold-free repair of polyimine composites with a curved surface at low temperature and pressure (similar to 75 degrees C, implemented by a handheld iron for 5 min). The malleability, weldability, and full recyclability of polyimine composites fabricated by the powder-based method are also demonstrated. These unique properties offer great promise for expanding the manufacturing capability and extending the service life of fiber-reinforced composites.

Automated summary

Polyimine is a covalent adaptable network with dynamic imine bonds, suitable for recycling, reprocessing, and repair. Through a powder-based compression molding method, carbon fiber-reinforced polyimine composites can be rapidly fabricated with mechanical properties similar to those produced through traditional methods. Additionally, in situ, mold-free repair of polyimine composites at low temperature and pressure was demonstrated, showcasing the malleability, weldability, and full recyclability of the material.