Experimental study of interlayer properties of carbon fiber reinforced thermoplastic composites based on CNT reinforcement

In this study, to address the common interlaminar cracking failure problem of continuous carbon fiber-reinforced thermoplastic composites (CCFRTP) laminates, the thermoplastic resin polyetherimide (PEI) was selected and carbon nanotubes (CNTs) were introduced into the PEI matrix to improve the interlaminar properties. The experimental results show that when the content of CNTs in the resin matrix is 6 wt%, the interlayer performance of the laminates is the best, and the interlayer fracture toughness in the stable expansion stage of mode I crack is increased by 131.61%; mode II interlaminar fracture toughness was increased by 347.38%. This is attributable to the introduction of CNTs, which not only serve as a bridging agent at the resin–fiber interface to extend crack propagation pathways, but also enhance the adhesion between resin and fibers. Consequently, the interlaminar failure mode shifts to resin fracture within resin-rich zones, thereby substantially improving the interlaminar mechanical properties of the composite laminate. This provides a theoretical foundation for further enhancing the comprehensive performance of CCFRTP laminates in future research.