Thermotropic liquid crystal-driven interfacial fusion of high-aspect-ratio polyarylate nanofibers for ultrastable honeycomb with closed-loop recyclability

Abstract

To address process and interface limitations in aramid honeycomb for aerospace and rail transportation, this work develops polyarylate (PAR) nanofibers with high aspect ratios using melt spinning coupled with wet dissociation, exploiting the liquid crystalline behavior of PAR to enhance molecular alignment and mechanical integrity. A scalable template thermal welding process was used to enable directional assembly and strengthen interfacial fusion in PAR nanofiber honeycomb (PAR NFHC), effectively mitigating stress concentration and delamination failures caused by fiber/resin interface mismatch in conventional aramid honeycombs. PAR NFHC demonstrates exceptional mechanical properties, with compressive strength, specific strength, and Young's modulus reaching 161 MPa, 290 kN·m·kg⁻¹, and 977 MPa, respectively-up to 40 times higher than commercial HC. Even after prolonged exposure to high temperatures (200 °C for 24 h) and ultraviolet radiation (24 h), PAR NFHC retains compressive strengths of 151.8 MPa and 146 MPa, respectively, with minimal degradation, whereas commercial HC experiences a substantial reduction to 1.8 MPa and 1.9 MPa. PAR NFHC exhibits excellent flexibility, enduring single-point bending at 45° and double-point bending at 30° without failure. The thermoplasticity of PAR NFHC enables closed-loop recycling, minimizing resource consumption while maintaining performance. This property positions PAR NFHC as a promising candidate for the sustainable development of high-performance honeycomb materials.