Effects of Adding Carbon Nanotubes/Hydroxyapatite Composites on the Properties and Structure of Calcium Phosphate Cement

The multi-walled carbon nanotubes (MWNTs)/hydroxyapatite (HA) composites were synthesized by three different methods, namely physical blending (PB), chemical coprecipitation (CC) and bionic immersion (BI), and used as one of solid phase powders for the preparation of calcium phosphate cement (CPC). For the addition of MWNTs/HA composites, CPC had an increasing hydrophilicity and a decreasing initial and final setting time. However, the initial setting time and final of CPC made of MWNTs/HA powders still met the clinical requirements for the biomedical applications. The addition of MWNTs/HA composites synthesized by different methods had great effect on the compressive properties of CPC and HA crystallinity in CPC, but had no effect on the phase composition of CPC. Compared with blank CPC, CPC-CC and CPC-BI, CPC-PB had the best compressive mechanical properties and the highest HA conversion and content. Compared with blank CPC, the compressive strength and elastic modulus of CPC synthesized by PB method increased 48.23% and 41.87%, respectively.