Manufacturing and performance of titanium dioxide-ultra high molecular weight polyethylene nanocomposite materials

Total joint replacement for the repair of diseased and injured hips has increased over the years. A major concern with these devices is the long-term durability of the materials in younger and more active patients. The common use of Polyethylene for the acetabular cup lining, contributes to implant loosening and failure due to wear debris-induced bone osteolysis. This study seeks to develop and characterize Titanium Dioxide-Ultra High Molecular Weight Polyethylene (TiO2-UHMWPE) composites as a possible alternative to existing materials to significantly reduce wear debris from acetabular components of hip implants. Motivation for the use of TiO2 stemmed from its low cost and its biocompatibility, while UHMWPE possesses qualities of biocompatibility, high material stiffness and low wear rate. From a number of material samples characterized in extruded and non-extruded forms using low and high pressure compression molding, the non-extruded form under high pressure compression was found to perform best. TiO2-UHMWPE composites were manufactured utilizing non-extrusion and high pressure compression molding. Varying weight percentages of TiO2 composites (0%, 10%, 20% and 30%) were then machined to form punch, block-on-ring wear and fracture samples. Mechanical tests were conducted for the varying weight percentages of TiO 2 with pure UHMWPE as the control. Punch testing exhibited an increase in peak load by 11%, 18% and 26% respectively with the addition of 10%, 20% and 30% TiO2. Wear testing revealed an increase in bi-linear wear rate by 1054% with the addition of 30% TiO2. Fracture testing demonstrated a decrease in fracture toughness by 17%, 72% and 93% respectively with the addition of 10%, 20% and 30% TiO2. Both the manufacturing process and characterization techniques used should prove useful in exploring the introduction of new materials in this field of study.