Preparation and Properties of the Hydroxyapatite/polylactic Acid (HA/PLA) Nanocomposites

The lipophilic hydroxyapatite (HA) nanorods were firstly synthesized by the solvothermal method using calcium oleate as the precursor. As-synthesized HA nanorods had an average aspect ratio of 11.4 with 18.4 wt% oleic acid attached on the surface. Then the hydroxyapatite/polylactic acid (HA/PLA) nanocomposites were prepared by dispersing the HA nanorods in PLA using dichloromethane (CH2Cl2) as the volatile solvent. The influence of the HA content on the properties of the HA/PLA nanocomposites was investigated. It is found that the nanocomposite with 2 wt% HA exhibits the optimal mechanical properties. The tensile strength and elongation at break are 59.4 MPa and 18.19%, respectively. The values are enhanced by 13% and 184.2% compared with that of the pure PLA. The higher HA addition results in the decrease in the mechanical properties due to the aggregation of HA nanorods. The thermal properties of the HA/PLA nanocomposites were also examined. It is found that the thermal stability and crystallization transition temperature are decreased while the glass transition temperature and melting temperature remain basically unchanged with the increasing HA content up to 10 wt%.