Abstract
The present study was aimed at investigating the effects of the sterilization method and accelerated aging on the wear and morphology of ultrahigh molecular weight polyethylene. In a first test, gamma- and EtO-sterilized acetabular cups were tested in a hip joint simulator for two million cycles. After the test, the cups underwent an accelerated aging treatment (80 °C, 4 weeks in air furnace) and were newly tested for another three million cycles. Wear was evaluated by gravimetric measurements, morphology by micro-Raman spectroscopy. During the first test, the EtO-sterilized cups underwent a significantly higher wear than the gamma-sterilized ones (62 and 30 mg/million cycles, respectively). No significant crystallinity changes were observed. Upon accelerated aging, the crystallinity increase of the gamma-sterilized cups was more pronounced than for the EtO-sterilized cups, due to chain scission and oxygen incorporation. In the second test, the wear rate of EtO-sterilized cups decreased to 38 mg/million cycles, while for gamma-irradiated cups it increased to 84 mg/million cycles. At the same time, the latter cups underwent significant increases in temperature and crystallinity, due to the higher friction. For the EtO-sterilized cups a significant decrease in crystallinity was observed, due to the occurrence of an orthorhombic → monoclinic phase transformation.
Original language | English |
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Pages (from-to) | 254-263 |
Number of pages | 10 |
Journal | Journal of Molecular Structure |
Volume | 875 |
Issue number | 1-3 |
DOIs | |
Publication status | Published - Mar 17 2008 |
Keywords
- Accelerated aging
- Acetabular cups
- Hip joint simulator
- Micro-Raman spectroscopy
- Polyethylene
- Sterilization
ASJC Scopus subject areas
- Structural Biology
- Organic Chemistry
- Physical and Theoretical Chemistry
- Spectroscopy
- Atomic and Molecular Physics, and Optics
- Materials Science (miscellaneous)