Reciprocating friction and wear performances of nanometer sized-TiO2 filled epoxy composites

Nanometer-sized particles, for example, TiO2, have gradually gained the attention to improve the mechanical and tribological properties of epoxy composite coatings. In the present paper, TiO2 with the size of 300 nm was applied to improve the reciprocating friction and wear performances of an epoxy composite. The effects of TiO2 content and sample preparation methods on the mechanical and tribological performances were investigated experimentally. It was found that the optimal mixture ratio of TiO2 was 4 wt%, and the tensile strength of composite increased by up to 30% compared with the control sample. The TiO2 nanoparticles were treated with polyvinylpyrrolidone (PVP) and then mixed into epoxy resin with three-roll mill grinding technique. The PVP molecules could surround a single TiO2 to form super-monomer, which produced repulsive force to aim to disperse nanoparticles, and the three-roll mill grinding could utilize the compression of axis surfaces and friction at different speeds to reduce the size of agglomerations of more than 5 microns. The results showed that the PVP molecules treatment could improve tensile strength and modulus, and three-roll mill grinding technique could enhance the elongation at break. In addition, the reciprocating wear rate and frictional coefficient of the epoxy composite plates also were reduced remarkably owing to the pretreatment of TiO2 particles, for example, and the frictional coefficient of epoxy composite decreased from 0.09 to 0.04 for the optimal ratio of TiO2, and special wear rate also decreased by 87.5% compared with the control sample. This was because the TiO2 nanoparticles acted as the stress transfer medium and could undertake part of loading to relieve stress directly into the epoxy matrix. There was a thin transfer film in which the particles acted as a membrane skeleton to avoid matrix further being torn. Because of the hardness and nanoeffect of particles, TiO2 could fill the defects in the wear interface to form a protective film and improve surface fatigue resistance property. The more uniform dispersion of TiO2 particles brought about the obvious improvement of wear resistance of composites.

Automated summary

Nanometer-sized TiO2 particles have been found to enhance the mechanical and tribological properties of epoxy composite coatings. The optimal mixture ratio of TiO2 is 4 wt%, with treated nanoparticles and a three-roll mill grinding technique significantly improving the tensile strength, modulus, elongation at break, wear resistance, and frictional coefficient of the composites. The uniform dispersion of TiO2 particles plays a key role in enhancing the wear resistance of the composites.