In Situ Preparation and Enhanced Mechanical Properties of Carbon Nanotube/Hydroxyapatite Composites

Carbon nanotubes (CNTs) are used as a reinforcing phase to strengthen and toughen hydroxyapatite (HA). Multiwalled carbon nanotube/hydroxyapatite composites (MWCNT/HA) are prepared by in situ chemical precipitation of HA on MWCNTs modified by polyvinyl pyrrolidone (PVP) wrapping or dodecyl benzene sulfonate (SDS) adsorption. The CNT/HA composites are obtained by vacuum hot-pressed sintering. Results show that PVP has good polymer-tube affinity and is a better dispersant than SDS for CNTs. Moreover, the distribution and bonding strength of CNTs in and with the HA matrix affect the mechanical properties of the composites. For an optimum addition of 3wt% PVP modified CNTs to HA, the fracture toughness and the flexural strength for the fully dense compact are increased by 260% and 50% over monolithic HA materials, respectively.