A coordination-connected flexible-rigid hybrid nanoparticles coating for the interfacial enhancement of carbon fiber/polyetheretherketone composites

Abstract

To date, carbon fiber (CF) reinforced polymer composites have found widespread application due to exceptional properties, including high specific strength and modulus, thermal stability, chemical durability. However, the interface serves as the bridge for load transfer between fiber and resin, the interfacial property directly affects the holistic performance of the composites. Therefore, considering the inertness of CF and polyetheretherketone (PEEK), and the modulus gap between them, we propose a flexible-rigid sizing agent for enhancing the interfacial adhesion and mechanical properties of CF/PEEK composites. The sizing layers are constructed by the hybrid nanoparticles of rare-earth coordination bonded flexible aramid nanofiber (ANF) and rigid nano-TiO2, and the transition layer of polyetherimide (PEI). The treatment with the flexible-rigid sizing agent significantly improves the active functional group content, surface roughness, and wettability of the CF. Meanwhile, as-prepared CF/PEEK composites show a remarkable enhancement both in mechanical and interfacial strength, which could be attributed to the synergistic effects of flexible-rigid structures, ultimately improve the external stress transfer and suppression of crack propagation. Herein, this work offers a robust and promising approach for the fabrication of high-performance CF/PEEK composites.