A polyethylene-reinforced polymer composite abraded by bulk solids

The abrasive wear characteristics of polymer matrix composite materials reinforced with particles of ultra-high molecular weight polyethylene (UHMWPE) have been investigated. Granular ignimbrite (a hard mineral) was used as the abrasive. The effect of varying the volume fraction of UHMWPE reinforcement upon wear rate has been measured and scanning electron microscopy (SEM) used to study the wear mechanisms that operate. The results demonstrate that there is a distinct transition that occurs in the dominant wear mechanism as the volume fraction of UHMWPE reinforcement is increased. In particular, as the UHMWPE concentration in the resin is increased, friction at the surface decreases and the wear mechanism appears to change from predominantly three- to two-body wear, with a corresponding decrease in wear rate. This transition in mechanism appears to occur when the wall friction drops below the internal friction of the granular bed. At higher values of wall friction, the plane of shear failure is within the granular material so that the particles in contact with the surface have a rolling component across the surface. At lower values of wall friction, the plane of shear failure occurs at the surface.