A Novel Bio-Nanocomposites Composed of Hydroxyapatite Reinforced with TiO2 Electrospun Nanofiber Consolidated Using High-Frequency Induction Heating

Abstract

Titanium dioxide (TiO2) nanofibers prepared by the electrospinning technique have been used as reinforcement to improve the fracture toughness of hydroxyapatite (HAp). The required TiO2 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 TiO2 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 TiO2 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 TiO2 nanofibers. The bending and compressive strength values of HAp/5 wt% TiO2 sintered compacts were 119 and 120 Mpa, respectively, in the case of the TiO2 nanofiber calcined at 800°C, while the strength decreased with the decreasing or by increasing calcination temperature higher than 800°C.

Fabrication of Dense Hydroxyapatite Nanobioceramics with Enhanced Mechanical Properties via Two‐Step Sintering Process

“…The fracture toughness (K IC ) of dense HAp was remarkably lower than that of human bone. [5][6][7] Unfortunately, most of these reinforcements are bioinert and/or nonbiocompatible, which remarkably decreases the bioactivity and biocompatibility of HAp-based materials, and should be avoided. 2,3 Therefore, there is a need to increase the mechanical properties, especially the fracture toughness.…”

“…Thus, the poor mechanical properties, especially the low toughness of HAp bioceramics have severely hindered their clinical applications, such as artificial bones or teeth. 5,6 The secondary phases of band a-TCP from HAp decomposition are degradable and will ultimately decrease the mechanical properties of the implants during the degradation. Several attempts had been applied to solve this problem, such as using glass as the liquid phase sintering additives to improve mechanical strength, 4 using ZrO 2 , TiO 2 , metals, and carbon nanotubes etc.…”

1D Titania Nanoarchitecture as Bioactive and Photoactive Coatings for Modern Implants: A Review

“…The synthesis involves the following four steps: (1) the preparation of the titania precursor sol, (2) mixing of the sol with the polymer template to obtain the solution for electrospinning, (3) electrospinning of the solution with the use of the apparatus showed in Figure 4, and (4) the calcination of as-prepared TNF to obtain crystalline titania nanofibers [164]. The morphology and the diameter of the electrospun titania depend on the following parameters related to: (a) the solution, (b) the process, and (c) the ambient ( Table 2), while the structure of formed nanofibers is strictly associated with the postcalcination process [165][166][167][168][169][170][171][172][173]. Another technique to produce titania nanofibrous coatings is the laser ablation, proposed by Tavangar et al [174].…”

“…Calcination temperature Higher temperature results in the reduction of nanofiber size, because of the loss of polymer and the crystallization process of titania [165,168,[171][172][173] Table 2. Summarization of the electrospinning parameters affected the nanofibers morphology.…”

Effect of ZrO2, TiO2, and Al2O3 Additions on Process and Kinetics of Bonelike Apatite Formation on Sintered Natural Hydroxyapatite Surfaces

“…2 So, it is only used in nonload areas of the human body such as the ossicles in the middle ear. [16][17][18] Fidancevska et al have shown that composite with 15% TiO 2 content improves mechanical properties. Several works have consequently been carried out on structural modifications and mechanical properties of HA in the presence of oxides or metallic dispersions used as reinforcing agents.…”