Tribological behaviour of modified polyacetal against MC nylon without lubrication
Compared with other polymers, polyacetal or polyoxymethylene (POM) which is widely used as bearing, guide, gear and other sliding parts, has high strength and stiffness, excellent chemical resistance and superior antifriction and wear resistance. To improve the toughness and self-lubrication capacity of POM due to its higher crystallizability, other components, which include toughening phase and solid lubricants, are often added to the POM matrix. This paper deals with the friction and wear behaviours of POM which was modified by the toughening phase polyurethane (PU) and filled with polytetrafluoroethylene (PTFE) and silicone oil, during rubbing against MC nylon without liquid lubrication. Friction and wear tests show the tribological performance of the modified POM (M-POM) with 10 wt% PU is better than those of pure POM and POM blended with PTFE under dry friction. The frictional coefficient of the M-POM decreases with increasing nominal load. The sliding velocity has a more obvious effect on the tribological properties of the M-POM than the nominal load. The higher sliding velocity leads to thermal degradation and melting of the experimental polymers because of the frictional heat.