Study On Fabrication And Mechanical Properties Of HA/PEEK Functionally Graded Biomaterials

In this paper, the hydroxyapatite reinforced polyetheretherketone functionally graded biomaterials (HA/PEEK FGBm) with total HA content were successfully prepared by in situ synthesis-layer-by-layer casting method and incorporation with thermal pressure molding technology. The microstructure and composition of HA/PEEK FGBm was analysised and characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Material universal testing machine system was used to study the influence of preparation conditions on the change law of the mechanical performance of HA/PEEK FGBm. Combination of microscopic morphology observation and analysis to reveal the HA/PEEK fracture mechanism under different conditions. In addiction, the bioactivity of HA/PEEK FGBm was studied through biological sedimentation experiments. The results were as follows:1. The results of the XRD analysis showed that heat treatment could improve the crystallinity of PEEK. The results of FT-IR analysis suggested that the HA/PEEK FGBm was a mixture of HA and PEEK. The results of SEM observation showed that the HA particles in the composite layer of the HA/PEEK FGBm was nanometer level, and found that the HA/PEEK FGBm had good interface bonding state.2. The results of tensile tests and three point bending test of HA/PEEK FGBm showed that the tensile strength, tensile strain, flexural strength and strain were decreased with the rise of HA content, on the contrary, the tensile and flexural modulus were increased with the rise of total HA content.3. The tensile properties of the HA/PEEK FGBm after annealing treatment was significantly higher than that of HA/PEEK FGBm before annealing treatment. The tensile strength of annealed (35/40/45) wt%HA/PEEK FGBm was29.18MPa and tensile modulus of that reached a maximum value of2.953GPa.4. Tensile test under stress concentration condition showed that the smaller cross-sectional area of notch, the greater stress concentration performance, and the damage on the mechanical properties of the material was greater. In addition, under stress concentration state, the tensile strength and modulus of (30/40/50) wt%HA/PEEK FGBm were higher than that of40wt%HA/PEEK composites. It suggested that moderate HA concentration difference between adjacent layers (HCDBAL) can alleviate the damage of stress concentration on the strength of the material, also showed that HCDBAL and total HA content were synergistic to the mechanical properties of HA/PEEK FGBm.5. Biological deposition experiments show that HA/PEEK composite material had good bioactivity. It was estimated that HA/PEEK FGBm had good bioactivity.