Polyarylate Nanofiber-Mediated Closed-Loop Recyclable PMIA Nanocomposite Honeycombs with Exceptional Strength and Extreme-Condition Stability

By 2025, global demand for aramid fibers is projected to surpass 140,000 tons, leading to significant waste. Traditional disposal methods such as incineration and landfill are harmful to the environment, while discarded aramid fibers hold significant recycling potential. Herein, we present a scalable wet-thermosetting method to fabricate a high-performance nanocomposite honeycomb (NCHC) from recycled poly m-phenyleneisophthalamide (PMIA) and in-house polyarylate (PAR) nanofibers, mimicking a “twining stem-like” architecture. During processing, PAR nanofibers intertwine with PMIA fibers, forming an interlocked network. Subsequent hot-pressing induces π–π conjugation and hydrogen bonding, creating a robust cross-linked structure. The resulting PMIA/PAR NCHC exhibits a compressive strength of 193 MPa and a specific strength of 321 kN·m/kg, which is 29 and 2.3 times greater than commercial honeycombs. Additionally, it demonstrates exceptional stability under extreme conditions, retaining 156.1 MPa after 24 h at 200 °C and approximately 90% of its original compressive strength following 24 h of UV exposure. The PMIA/PAR NCHC also withstands bending and torsional deformation up to 60° without failure. Furthermore, PMIA/PAR NCHC can be fully regenerated via a physical closed-loop recycling process while preserving its structural integrity and lightweight characteristics. This work provides a sustainable pathway to valorize aramid waste into high-performance composites suitable for demanding engineering applications.