Multifunctional N-doped MXene/Ammonium polyphosphate reclaimed carbon fiber veil for enhanced electromagnetic shielding, flame retardance, and thermal efficiency

The application of carbon fiber reinforced plastics (CFRPs) in various industries significantly increased the need for sustainable recycling of carbon fiber (CF) to enhance economic efficiency. In this study, we prepared lightweight multifunctional flame-retardant Ti₃CNT_x/Ammonium Polyphosphate (APP)/Polyethyleneimine (PEI)/reclaimed carbon fiber (MArCF) nonwoven veils with superior Electro-Magnetic Interference (EMI) shielding effectiveness (SE) using a combination of multiple vacuum-assisted filtration, improved etching, and delamination strategies, followed by annealing treatments. The resulting MArCF nonwoven veils exhibited an impressive EMI SE of a maximum of 72.65 dB, with a SSE/t value reaching 10730 dB cm² g⁻¹. Moreover, the MArCF nonwoven veil demonstrated excellent flame retardance properties, with a substantial decrease of 63 % in Heat Release (HR) capacity, 60 % in Total Heat Release (THR), and 83.15 % in Heat Release Rate (HRR). The modified veils also exhibited excellent Joule heating and photothermal properties, indicating a promising potential for multifunctional reinforcement in composites.