Multiscale Carbon Nanotube-Carbon Fiber Reinforcement for Advanced Epoxy Composites with High Interfacial strength

In this study, carbon nanotubes were chemically grafted on carbon fibers using PAMAM functionalization. Single-fiber composites with the carbon nanotube/carbon fiber (CNT/CF) multi-scale reinforcement were fabricated to examine the influence of local nanotube reinforcement on load transfer at the fiber/matrix interface. Molecular simulations of the epoxy resin composites with a CNT/CF multi-scale reinforcement and an unsized CF were performed employing Materials Studio 4.0 software. Results show that the interfacial shearing strength (IFSS) of the CNT/CF composite is up to 116.98 MPa, an increment of 170% in comparison with that of the unsized T300 CF composite. The results of molecular simulations show that interaction energy of CNT/CF multi-scale composite is up to 929.83 kcal/mol, which is 2.7 times higher than that of the unsized one. This significant enhancement of interfacial shear strength can be attributed to two aspects: (i) Van der Waals binding and mechanical interlocking increase due to the CNTs addition, (ii) chemical bonding and surface wetting increase caused by the layer of PAMAM dendrimers.