A Novel Bio‐Nanocomposites Composed of Hydroxyapatite Reinforced with TiO ₂ Electrospun Nanofiber Consolidated Using High‐Frequency Induction Heating

Titanium dioxide (TiO ₂ ) nanofibers prepared by the electrospinning technique have been used as reinforcement to improve the fracture toughness of hydroxyapatite (HAp). The required TiO ₂ nanofibers with diameters of 50–400 nm were first prepared by the calcining and presintering of as‐prepared electrospun nanofibers of polyvinyl acetate (PVac)/titania composite at different temperatures. The composite consisting of HAp and 5 wt% of electrospun TiO ₂ nanofibers was then sintered at 1050° C by the high‐frequency induction heat‐sintering technique and its mechanical properties are evaluated by three‐point bending tests, indentation tests, and a compression test. The results indicated that the morphology and crystalline phase of TiO ₂ nanofibers were strongly influenced by the calcination temperature. Additionally, the scanning electron microscopic results showed that the nanofibers calcined at 600°C are a porous structure due to the low densification. There was a significant change of microstructure by increasing the calcination temperature to 800°C. The nanofibers appeared with a dense microstructure due to the high‐temperature calcination. A number of large size particles or particle aggregates connected by a small neck were found after the nanofibers were calcined at 1000°C. The sintering behaviors, toughness, and hardness of the resulting composites were significantly affected by the calcination temperature of the included TiO ₂ nanofibers. The bending and compressive strength values of HAp/5 wt% TiO ₂ sintered compacts were 119 and 120 Mpa, respectively, in the case of the TiO ₂ nanofiber calcined at 800°C, while the strength decreased with the decreasing or by increasing calcination temperature higher than 800°C.