Chemical stability of oil-infused polyethylene. (April 2021)

• Record Type: Journal Article
• Authors: Zaribaf, Fedra P; Gill, Harinderjit S; Pegg, Elise C
• Is Part Of: Journal of biomaterials applications. Volume 35:Number 9(2021)
• Page Start: 1168
• Page End: 1179
• Publication Date: 2021-04
• Subjects: Medical polyethylene -- antioxidant -- radiocontrast -- thermal ageing -- joint replacment -- mechanical testing; Biomedical engineering -- Periodicals; Biomedical materials -- Periodicals; 610.28
• DOI: 10.1177/0885328220977353
• Languages: English
• ISSNs: 0885-3282

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.