Browse by author
Lookup NU author(s): Emeritus Professor Jim White
Full text for this publication is not currently held within this repository. Alternative links are provided below where available.
The aging behavior of ultra-high molecular weight polyethylene (UHMWPE) has been studied following gamma irradiation in air. Accelerated aging procedures used elevated temperature (70°C), pressurized oxygen (5 bar) and applied stress. Shelf and in vivo aged components have also been investigated. The variation in polymer properties with depth into the polymer was determined using density measurements, infra-red spectroscopy and differential scanning calorimetry. Accelerated aging in pressurized oxygen resulted in peaks in polymer density and degree of oxidation up to 500 μm below the polymer surface. Shelf and in vivo aging was also found to result in increased density at or below the component surfaces. Changes in density were mainly due to changes in crystallinity within the UHMWPE and, to a smaller extent, due to oxygen incorporation within the polymer. The application of stress did not appear to influence the accelerated aging of UHMWPE. A method for estimating the residual stress distribution in the UHMWPE using the measured changes in density is proposed. This study has indicated that oxidation of UHMWPE may lead to the development of tensile residual stresses, near the component surface, in the region of 1.7 MPa. These stresses may contribute to the failure mechanism of UHMWPE acetabular cups or knee tibial trays during service. © 2001 Kluwer Academic Publishers.
Author(s): White JR; Buchanan FJ; Sim B; Downes S
Publication type: Article
Publication status: Published
Journal: Journal of Materials Science: Materials in Medicine
Year: 2001
Volume: 12
Issue: 1
Pages: 29-37
Print publication date: 01/01/2001
ISSN (print): 0957-4530
ISSN (electronic): 1573-4838
Publisher: Springer
URL: http://dx.doi.org/10.1023/A:1026796817483
DOI: 10.1023/A:1026796817483
Altmetrics provided by Altmetric
