Highly Tear-Resistant Recyclable Carbon Fiber Reinforced Composites Relying on Woven Cross-Linked Polyurethanes

The poor ductility and irreversible properties of covalently cross-linked polymers result in carbon fiber-reinforced polymer composites (CFRPs) with low tear resistance and nonrecyclability. In this work, a flexible woven polyurethane (WPPN_n) prepared via a woven cross-linker was used for the first time as a binder for CFRPs. WPPN₂₀₀₀ exhibited an ultrahigh strength of 50.4 MPa, a toughness of 267.2 MJ m^-3, and an excellent fracture energy (211.6 kJ m^-2). Simulation results and characterization tests confirmed the high energy dissipation of the woven network. The WPPN₂₀₀₀-CF composites achieved a tear resistance of 1004.5 kJ m^-2, which is 16.4 times higher than that of the epoxy-CF composites (61.2 kJ m^-2). In addition, due to the dynamic nature of the woven cross-linking, the carbon fiber can be recovered nondestructively using solvent. The woven cross-linking strategy provided new ideas for the design of carbon fiber adhesives.