Free-Standing CNT Film for Interlaminar Toughening: Insight into Infiltration and Thickness Effects

Carbon fiber reinforced polymer composites have the advantages of being lightweight, having high strength and designability, and having been extensively used. However, the interlaminar toughness and delamination resistance of these composites are relatively poor due to their laminated structure and intrinsic brittleness of resin matrix. In this paper, commercialized free-standing carbon nanotube (CNT) films, drawn from CNT forests, were used to toughen the interlaminar interfaces of the composites. The effects of resin infiltration state and thickness of CNT films on the interlaminar toughening effect were systematically investigated. The results show that the pre-infiltration treatment of CNT films with acetone diluted epoxy resin solution can effectively improve the degree of resin infiltration. Compared with the samples containing untreated CNT film, the Mode I and Mode II interlaminar fracture toughness of the treated samples were significantly improved. The GIC reached a maximum of 1412.42 J/m2 at a CNT film thickness of 5 & mu;m, which was about 61.38% higher than that of the baseline. At a CNT film thickness of 15 & mu;m, the GIIC reached a maximum value of 983.73 J/m2, approximately 67.58% higher than that of the baseline. The corresponding toughening mechanisms were also systematically analyzed.

Automated summary

This paper investigates the use of commercial free-standing carbon nanotube films to enhance the interlaminar interfaces of carbon fiber reinforced polymer composites. By pre-treating the films with acetone diluted epoxy resin solution, the degree of resin infiltration and the interlaminar fracture toughness of the composites were significantly improved. The results show that at a thickness of 5 μm, the GIC reached a maximum of 1412.42 J/m2, which is 61.38% higher than the baseline. At a thickness of 15 μm, the GIIC reached a maximum value of 983.73 J/m2, approximately 67.58% higher than the baseline.