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 (∼130 °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 ∼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 (∼75 °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.