The Effect of Preparation Methods on Tribological Properties of PVA-H/HA Composites

Nano hydroxyapatite (HA) is a potential artificial cartilage material. To study its friction and wear properties, nano hydroxyapatite (HA) particles filled with polyvinyl alcohol hydrogel (PVA-H) composites were slid against a stainless steel disk under water lubrication condition using an improved four-ball tester. The worn surfaces were investigated by using a scanning electron microscope (SEM) to determine the wear mechanisms of pure PVA-H and PVA-H/HA composites prepared by different methods. Experimental results show that the addition of HA slightly decreases the friction coefficient of composites with the increase of HA content under water lubrication condition. The wear resistance of the PVA-H matrix was also improved by the introduction of HA inorganic component. It was also found that the PVA-H/HA composites prepared by in situ synthesis have better tribological properties than the composites prepared by mixed method with the same components and test conditions. The SEM photos show that the wear mechanisms of PVA-H/HA composite prepared by the mixed method with high HA content showed abrasion and adhesion, while that of the composite prepared by in situ synthesis was slightly scratched and fatigued. These results may be useful in the tribological designs for artificial articular cartilage material.