Effect of LaCl3 Surface-Modified Carbon Nanotubes on Tribological Properties and Thermal Stability of Carbon Nanotube–Reinforced Epoxy Resin Composites

In this article, rare earth (RE)-modified carbon nanotubes (CNTs) were obtained by surface modification of multiwalled carbon nanotubes (MWCNTs) with rare earth LaCl3, and composite materials were prepared by using epoxy (EP) resin as the matrix. The modified CNTs were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The tribological properties and thermal stability of the composites were tested using a multifunctional tribological tester and TGA. The surface wear morphology of the composite and the dispersion of the CNTs in the composite were characterized by scanning electron microscopy. Studies have shown that RE-modified CNTs can indirectly improve the initial decomposition temperature of the composites, which is beneficial to the thermal properties of the composites. Moreover, the modified CNTs can obviously improve the tribological properties of the composites, in particular, they can reduce the wear rate (WR). Compared to pure EP, the coefficient of friction (COF) and WR of the composites were reduced by over 19 and 90%, respectively.