Tax policy developments, donor inflows and economic growth in Malawi

Abstract

In this investigation the friction and wear performance of GUR 1020 medical grade ultra-high molecular weight polyethylene (UHMWPE) polymer under dry sliding, distilled water and egg albumen lubrication conditions were evaluated. The sliding experiments were carried out on a pin-on-disc tribometer. The contact configuration used was a polymer pin on a rotating AISI 304L stainless steel disc. Wear tests were carried out for 30 min duration at room temperature with 50, 100 and 150 N applied load values and at 0.50, 1.0 and 2.0 m/s sliding speeds condition. The results show that the coefficient of friction for GUR 1020 medical grade UHMWPE polymer is more significantly influenced by applied load and sliding speed values under dry sliding condition rather than lubricant media condition. Furthermore, the coefficient of friction and specific wear rate increases with the increase in applied load and speed values. This increase is much pronounced under dry sliding condition. Moreover, for the range of load and speed values of this study the specific wear rate using egg albumen lubricant registered lower values than that of the distilled water lubricant and the dry conditions. Finally, the specific wear rate values for GUR 1020 medical grade UHMWPE polymer under dry, water lubricant and egg albumen lubricant conditions are at the levels of 8x10-14, 1.4x10-14 and 0.5x10-14m2/N respectively.   Key words: Medical Grade UHMWPE, tribology, distilled water, wear.