A bioinspired carbon nanotube/graphite oxide/epoxy interlaminar region for simultaneously strengthening and toughening glass fiber fabric/epoxy laminated composites

The intrinsic layered structure of laminated composites renders them prone to delamination and exhibits low fracture toughness, thereby limiting their full potential in practical applications. Inspired by the remarkable strength-toughness balance observed in natural structures such as nacre, a multi-walled carbon nanotubes/graphite oxide (MWCNTs/GO) hybrid through chemical bonding was developed; subsequently, this hybrid was deposited onto glass fiber fabric (GFf) via a straightforward yet highly efficient bottom-up assembly process. After epoxy injection, a nacre-mimetic architecture, characterized by brick-like GO nanosheets, anchor-like MWCNTs, and mortar-like epoxies, was successfully formed within the matrix-rich interlaminar region. By adjusting the MWCNTs:GO mass ratios and the chain length of aliphatic diamine, the structural integrity and properties of the laminated composites were significantly optimized. Under optimal conditions, the resulting laminated composites exhibited simultaneous improvements in strength and toughness. Specifically, compared to pure GFf-reinforced composites, the interlaminar shear strength and work of fracture increased by approximately 47 % and 363 %, respectively, demonstrating significant strengthening and toughening effects. Additionally, the maximum storage modulus was achieved in both the rigid glassy state and the softened rubbery state, while the glass-transition temperature was notably elevated, indicating enhanced thermal stability. This study offers a promising approach for designing and fabricating high-performance fiber-reinforced composites.