Friction and Wear of Polyphenylene Sulfide (PPS), Polyethersulfone (PES) and Polysulfone (PSU) Under Different Cooling Conditions

The friction and wear properties of polyphenylene sulfide (PPS), polyethersulfone (PES) and polysulfone (PSU), which have similar molecular structure, were investigated using an end-face contact tribometer in three different cooling ways: sliding without air cooling, sliding with air cooling, and sliding in water. The worn surface and wear debris were observed using a scanning electron microscope (SEM). The effect of frictional heat on the tribological properties of the polymers was comparatively studied. When sliding in air, with increasing applied load, the wear rate of PPS decreased slightly initially then increased later while the wear rate of PES and PSU increased through out. The results suggested that the friction coefficient was mainly affected by the temperature of the worn polymer that was controlled by the balance of heat flow of the whole sliding contact system. When sliding in water, the friction coefficients of the three polymers decreased compared to that sliding in air and remained relatively steady through the whole process under different load. The wear rates of the three polymers had a close value and, remarkably, increased compared to that sliding in air. The water cooling and lubrication role decreased the tribological properties difference between the polymers.