High strength and bioactive hydroxyapatite nano-particles reinforced ultrahigh molecular weight polyethylene

Nano-sized hydroxyapatite (HA) particles reinforced UHMWPE composite was developed for biomedical applications. The biocomposite with HA volume fraction of 0.5 was successfully processed by combined swelling/twin-screw extrusion, compression molding, and then hot drawing. SEM and EDAX characterization revealed that HA nano-particles were homogeneously dispersed in UHMWPE. WAXD showed that hot drawing effectively oriented the UHMWPE chains along the drawing direction. The composite exhibited tensile strength of 100 ± 22 MPa after hot drawing, which was comparable to that of cortical bone. The composite also exhibited great ability of inducing calcium phosphate precipitates on its surface in simulated body fluid, which was widely accepted as an indication of bioactivity.