Preparation and tribological behavior of RC2540-melamine-formaldehyde resin microcapsules

Pentasulfid bis(2, 2, 4-trimethyl) pentyl (RC2540)-melamine-formaldehyde resin microcapsules was synthesized by in-situ polymerization method with sulfureted fatty additive RC2540 as core materials and melamine-formaldehyde resin (MF resin) as shell materials. FTIR, thermo-gravimetric analysis and SEM measurements were used to characterize these microcapsules. The friction and wear properties of RC2540-MF resin microcapsules were investigated with four-ball testing machine using polyethyleneglycol as base fluid. The experimental results reveal that the friction coefficient can be as low as 0.04 under the lubrication of the base oil with 3% mass fraction of RC2540-MF resin microcapsules in 314 N load, the wear diameter under 314 N load(with 5% mass fraction of RC2540-MF resin microcapsules) is 0.54 mm, the experimental load can be increased to 1000 N above. The effect of RC2540-MF resin microcapsules in reducing friction and wear may be attributed to the physical and chemical adsorption on the friction surface, and to the tribochemical reaction film by active sulfides released from broken RC2540-MF resin microcapsules, leading to anti-friction, good extreme pressure and anti-wear property.