Investigation of Carbon Reinforced UHMWPE Nanocomposites for use in Orthopaedics

Abstract: Over the lifetime of a person, the function of the natural hip joint can be altered due to trauma or disease and an artificial hip replacement may eventually be required. Ultra high molecular weight polyethylene (UHMWPE) is considered the gold standard material for the acetabular cup in hip arthroplasties. However, problems associated with the release of UHMWPE wear particles, due to the relative motion between the bearing components, can lead to the eventual failure of the implant. The first part of this thesis focuses on reviewing the current status of total joint replacement research, with particular attention to implant bearing materials, implant wear particles and biological responses to wear particles. Subsequently, the thesis focuses on the potential of UHMWPE-based nanocomposites as an alternative to UHMWPE. A suitable method to prepare carbon nanoparticle reinforced UHMWPE materials was developed, and the possibilities of multi-walled carbon nanotubes (MWCNTs) and graphene oxide (GO) as reinforcements of UHMWPE were investigated.The results of this thesis showed that, under optimised conditions, carbonnanoparticles have the ability to improve the overall performance of UHMWPE,without adversely affecting the biocompatibility. However, further investigations into appropriate GO and MWCNT surface modification methods are necessary to enhance the filler/matrix interaction and further improve the performance of the resulting nanocomposites. This thesis has provided an insight into the potential of UHMWPE-based nanocomposites as an alternative to UHMWPE for use in total joint replacements and further work concerning biological and mechanical characterisation has been suggested in order to fully understand the behaviour of these nanocomposites.