Oxidative and Chemical Stability of Polyethylene is Enhanced by Oil Infusion

Research output: Contribution to journalArticlepeer-review

Abstract

Ultra-high molecular weight polyethylene (UHMWPE) can be made radiopaque for medical imaging applications through the diffusion of an iodised oil-based contrast agent (Lipiodol Ultra Fluid). A similar process is used for Vitamin~E incorporated polyethylene which provides antioxidant properties. This study aimed to investigate the critical long-term properties of oil-infused medical polyethylene after 4 weeks of accelerated thermal ageing. Samples treated with an oil (Vitamin E or Lipiodol) had a higher oxidation stability than currently used medical grade polyethylene, indicated by a smaller increase in oxidation index after ageing (Vitamin E +36%, Lipiodol +40%, Untreated +136%, Thermally treated +164%). The tensile properties of oil treated polyethylene after ageing were significantly higher than the Untreated and Thermally treated controls (p>0.05) indicating less mechanical degradation. There was also no alteration in the percentage crystallinity of oil treated samples after ageing, though the radiopacity of the Lipiodol treated samples reduced by 54% after ageing. The leaching of oil with time was also investigated; the leaching of Lipiodol and Vitamin E followed the same trend and reached a steady state by two weeks. Overall, it can be concluded that the diffusion of an oil-based fluid into polyethylene not only increases the oxidative and chemical stability of polyethylene but also adds additional functionality (e.g. radiopacity) providing a more suitable material for long--term medical applications.
Original languageEnglish
Pages (from-to)1168-1179
JournalJournal of Biomaterials Applications
Volume35
Issue number9
Early online date26 Dec 2020
DOIs
Publication statusPublished - 1 Apr 2021

Keywords

  • Medical polyethylene
  • Antioxidant
  • Radiocontrast
  • Thermal ageing
  • Joint replacement
  • Mechanical testing

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