Enhancing interlaminar fracture toughness of carbon fiber/epoxy composites toughened by polyethersulfone resin and hybrid carbon nanotubes/graphene oxide

Abstract In this study, to improve the interlayer fracture toughness of carbon fiber reinforced polymer (CFRP) composites, polyethersulfone (PES)/carbon nanotubes (CNTs)/graphene oxide (GO) hybrid films were prepared by wet phase transition method based on a total of seven different ratios of CNTs and GO, 0:5, 1:4, 2:3, 1:1, 3:2, 4:1, and 0:5 (with a total concentration of 1 wt%). The optimal toughening system of hybrid particles mixed with thermoplastic resin films for CFRP composites was investigated by the double cantilever beam test and end notched flexure test. The results showed that when 20 wt% of PES was added to the film and the ratios of CNTs to GO were 3:2 and 2:3, respectively, the Mode I and II fracture toughness of the laminates were significantly enhanced. Compared with the original specimens, the increases were 123.66% and 204.55%, respectively. In addition, CNTs/GO = 3:2 had the best enhancement effect on the Mode I test, increasing by 111.84%, filling the gap in the effect of low temperature environment on the interlayer fracture performance of high‐performance composites. Finally, a scanning electron microscope was used to observe the microstructure of the fracture surface and analyze the toughening mechanism. Highlights Seven hybrid films with different ratios were prepared. The superiority of film for enhancing the fracture toughness was verified. Fills the gap in the interlayer toughness of samples at low temperature.