Characterization of Enhanced UHMWPE-Hap Composites Manufactured by Hot Pressing

In the present study, a hip joint cup/liner material has been developed using ultra high molecular weight polyethylene (UHMWPE) matrix material which is reinforced by hydroxyapatite (HAp) particles with the 0.5, 1, 2, and 4 wt.% using mechanical activation followed by hot pressing. The main goal of the present study is to increase the life cycle of UHMWPE joint material, increasing wear resistance with HAp. The homogeneous distribution of HAp particles was confirmed by scanning electron microscopy (SEM) and the presence of characteristic peaks of UHMWPE and HAp was detected by x-ray diffraction (XRD) analysis. It was concluded that the hardness value of the UHMWPE-4 wt.% HAp composite increased by 118%, the wear rate decreased by 81%, and the coefficient of friction decreased by 65% compared to pure UHMWPE. The presence of an apatite structure was detected in the in vitro experiments performed after the UHMWPE-4 wt.% composite was kept in simulated body fluid (SBF) solution at 37 degrees C for 8 days. Differential scanning calorimetry (DSC) analysis revealed an increase of 7.91% in the melting temperature and 159% in the crystallinity value of pure UHMWPE with HAp reinforcement. All results revealed that UHMWPE-HAp composites demonstrate suitability for application as cup and/or liner components in hip joint prosthetic systems.