TRIBOLOGICAL CHARACTERISTICS OF FILLED ULTRAHIGH MOLECULAR-WEIGHT HIGH-DENSITY POLYETHYLENE

The dry sliding wear behaviour of filled ultrahigh molecular weight hi gh density polyethene (Uhmwhdpe) as influenced by different filler con centrations (3-10wt.%) was investigated. The fillers employed were gra phite, molybdenum disulphide (MoS2) and silica gel. Depending on the t ype of filler, a moderate increase in filler content resulted in a var iable increase in wear rate for all the fillers investigated. However, a larger increase in the filler content (above 5%) led to a decrease in the wear rate for graphite and MoS2 filled Uhmwhdpe, while the wear rate increased for silica gel filled Uhmwhdpe. These findings are dis cussed with reference to material properties, thermal effects and coun terface interactions. Explanations are also advanced to correlate the changes in lattice structure and the difference in wear behaviour of t he filled polymer.