Date of Award

Fall 1994

Document Type

Thesis

Degree Name

Master of Science in Biomedical Engineering - (M.S.)

Department

Biomedical Engineering Committee

First Advisor

Clarence W. Mayott

Second Advisor

Michael Pappas

Third Advisor

Georghios Makris

Abstract

Understanding friction and wear of biomaterials is essential to the success of any prosthetic joint. A pin-on-disc wear tester is used to find the friction and wear of pins of one material on a coupon of medical grade cobalt chrome. In this experiment six pins of UHMWPe (ultra high molecular weight polyethylene) and six pins of Hylamer® from Du Pont Manufacturing were tested. Four separate runs were made. The tests were performed for ten million cycles, stopping every one to one and a half million cycles for data acquisition. Volumetric wear, wear rate, and coefficients of friction were measured. Both polarized light photomicrography and Scanning Electron Microscopy (SEM) were used to analyze the samples. With the SEM, Kevex Analytical software for elemental analysis was used upon completion of the tests in order to determine and characterize the surface condition and its composition.

SEM and photomicrographic analysis indicated that although data between tests was not reproducible, early tests were reliable. Examination of the coupons showed that the of Hylamer® tests had greater surface degradation than the UHMWPe and the of Hylamer® itself wore at a moderately faster rate than the UHMWPe More testing will be needed to firmly confirm this result.

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