Mechanical and Electrical Properties of Epoxy/Multi-walled Carbon Nanotube/Nanoclay Nanocomposites

Among different types of nanoparticles, carbon nanotubes have always been the subject of extensive studies. In the present study, the effect of concurrent presence of multi-walled carbon nanotubes (MWNT)s and nanoclay on the electrical and mechanical properties of an epoxy system was investigated using the ultrasonic technique for dispersion of nanoparticles. First, an optimum amount for each type of filler is obtained in order to choose appropriate contents of clay/MWNTs components in nanocomposite samples. A nanocomposite reinforced with 0.5 wt% MWNTs showed higher modulus compared with a nanocomposite enhanced with 5 wt% nanoclay, implying that a lower content of MWNTs can lead to higher Young's modulus. Moreover, it was found that the electrical conductivity could be achieved by adding MWNTs. However, addition of nanoclay to epoxy/MWNTs nanocomposite would hinder its electrical conductivity. Simultaneous presence of MWNTs and nanoclay enhanced the Young's modulus and fracture toughness of the prepared nanocomposites. However, the tensile strength of all nanocomposites decreased except for those reinforced with 0.5 wt% MWNTs which showed an increase of around 7%. The SEM micrographs were used for the fractography of specimens and investigation of the dispersion state of MWNTs in the matrix. It was observed that fillers of different shapes provide different features on the fracture surface due to different mechanisms in their toughening action. The X-ray diffraction (XRD) was used to determine the d-spacing of nanoclay layers. The results showed that d-spacing of layers increased from 18.42 angstrom to 42.28 angstrom and thus an intercalated nanocomposite was obtained.