Establishment of interlaminar structure and crack propagation in carbon fiber reinforced epoxy composites by interleaving CNTs/PEK‐C film

Abstract

AbstractThe synergistic combination of carbon nanotubes (CNTs) and thermoplastic (TP) resin has shown the large potential in the improvement of fracture resistance for the epoxy matrix composites using the interleaving toughening method in recent years. The hybrid structure of CNTs and TP resin in interlayers affects directly the interlaminar structure and the resultant crack propagation path. In this work, the CNTs and thermoplastic polyetherketone‐cardo (PEK‐C) were used to prepare the interlayer of different structures to interleave the carbon fiber reinforced epoxy composites and the influence of hybrid structure on the interlaminar structure and the fracture toughness was investigated. The results showed that compared with the PEK‐C/CNTs uniformly hybrid interlayer, the sandwich interlayer produced better toughening effect in mode I interlaminar fracture toughness (GIC). The GIC was improved by 138.1% via PEK‐C/CNTs/PEK‐C sandwich interlayer, while only 49.7% via PEK‐C/CNTs hybrid interlayer. The sandwich interlayer resulted in the formation of the multilayered structure in the interlaminar region, facilitating the tortuous crack propagation path.