Thickness and pore effect of nanotube interleaves on interlaminar shear properties of carbon fibrous laminates

Carbon nanotube buckypaper (CNTBP)-based interleaves can significantly improve the interlaminar properties of fibre reinforced plastics. But previous studies mainly consider the reinforcing effect of a single as-prepared CNPBP, while some structural factors such as thickness or porosity of the CNTBP have scarcely been considered. This research introduces various thicknesses and porosities of CNTBPs into the middle interface of a carbon fibre reinforced plastic (CFRP) with a low resin matrix fraction of 37 ± 2 wt%. Results show that with a CNTBP thickness of 0∼28 μm (corresponding CNT/epoxy interleaf thickness is 0∼45 μm), mode II interlaminar fracture toughness (G_IIC) and interlaminar shear strength (ILSS) of the CFRP will increase by 0∼44.9% and 0∼9.5%, respectively, when compared to the base CFRP. If some ordered macro-pores (22.4 vol%) are introduced into the traditional CNTBP, the macro-porous CNTBP with a thickness range of 0∼48 μm (or the CNT/epoxy interleaf thickness is 0∼100 μm) will enhance the G_IIC and ILSS by ∼166% and ∼20%, when respectively compared to the baseline values. That is the thickness and macro-pore of CNTBP has a great effect on the interlaminar shear properties of the CFRP. Moreover, the proposed method does not change the design and manufacturing of CFRP and the CNTBP is introduced flexibly without pre-infiltration.