Fabrication and Characterization of Carbon Nanotubes/Fluorhydroxyapatite Composites

Hydroxyapatite (HA) ceramics have important biomedical applications as hard tissue replacements. However, the mechanical properties and chemical stability of HA ceramics in physiological environments need to be tailored for specific applications. To improve the mechanical properties of HA ceramics, carbon nanotubes (CNTs) are introduced into HA matrix materials by an in-situ chemical synthesis method. Meanwhile, fluorine is also incorporated into the HA structure to form fluorine-substituted hydroxyapatite (FHA). A uniform distribution of CNTs and good interfacial bonding help to improve the hardness by 76.2% and fracture toughness by 74.5% compared to pure HA. Both the dissolution behavior and antibacterial activities of CNTs/FHA composites show close relativity with the fluorine content. Increasing the fluorine contents of CNTs/FHA composites increases their chemical stability and ability to inhibit Streptococcus mutans.