Characterization of friction and wear of phenolic resin matrix composites reinforced by bamboo fibers of alkaline and LaCl3 treatment

Abstract

Mechanical and tribological properties of phenolic resin matrix composites reinforced by bamboo fibers, which were pre-treated with sodium hydroxide (NaOH) and post-treated with lanthanum chloride (LaCl3), were characterized by hardness, impact, microscratch tests, friction and wear testers, and thermogravimetric analysis. Bamboo fibers before and after modification were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Hemicellulose and lignin of bamboo fibers can be dissolved by alkaline or NaOH treatment, resulting in a rough surface. The high coordination number of rare earth atoms in LaCl3 solution enhanced the formation of chemical bonds between the hydroxyl groups of bamboo fibers and the oxygen-containing groups on the molecular chain of phenolic resin. The hardness and impact strength of the composites both firstly increased and then decreased with an increase in LaCl3 concentration or soaking duration in LaCl3 solution. Tribological performance (e.g. high-temperature friction coefficient, wear rate, thermogravimetric loss, crack propagation) of phenolic resin matrix composites was significantly improved by the treated bamboo fibers. The optimum mechanical and tribological properties of bamboo fiber-reinforced phenolic resin matrix composites were achieved under the conditions of LaCl3 concentration of 10% and soaking duration of 30 min.