Preparation Technology Development Of Hydroxyapatite Matrix Artificial Bone

Hydroxyapatite(HA) from the invention has been nearly half a century, its excellent biocompatibility and cell affinity and capacity in the field of artificial materials due attention. Hydroxyapatite is affected by itself brittle and mechanical properties, limiting its own applications in bone biomaterial. Therefore, toughening of HA with a second phase has been extensively explored to overcome the deficiencies of pure HA. Graphene oxide(GO) and Ni Ti exhibits excellent performance in mechanical and biocompatibility properties, and therefore GO and Ni Ti was proposed to toughen HA in this research. The preparation technologies and properties of two kinds of HA composites were studied, which could proprose a new kind of prepration technology for HA material.The gelcasting technology for preparing GO/HA and Ni Ti/HA composites was studied. The effects of p H, dispersant, solid contents of HA slurries, GO and Ni Ti particles on fluidity, stability and filling mould of the HA slurries were analyzed. The effects of initiator and catalyst on solidification time and integrity of HA composites were studied. The solidification mechanism of HA composites was analyzed. The effects of the contents of monomer, catalyst and solid contents of HA slurres on green density and comressive strength of GO/HA and Ni Ti/HA compacts were studied. The bending strength and fracture toughness of GO/HA and Ni Ti/HA composites with different GO and Ni Ti contents sintered at different temperature were measured. The microstructure of the fracture surfaces of the HA composites were observed and best preparing technology is determined. The strengthening and toughing mechanism was analyzed. The results show that at p H of 10, organic monomer of 15wt%, dispersant of 6wt%, GO of 1.5wt% and solid content of slurries of 45wt%, the GO/HA slurries have the better stability, fluidity, and filling mould. At p H of 10, organic monomer of 15wt%, dispersant of 5wt%, Ni Ti of 7wt% and solid content of slurries of 45wt%, the Ni Ti/HA slurries have the better stability, fluidity, and filling mould. With the increase of the contents of catalyst, the solidified time decreases, but the contents of initiator have little effect on the solidified time of GO/HA and Ni Ti/HA slurries. At the monomer of 15wt%, catalyst of 0.9 wt% and slurry solid content of 45wt%, the green compacts have better green density and compressive strength, 155.7% and 56.8%, 15.2MPa and 16.5MPa, respectively. The solidified time of two kinds of HA composites is 18 min.When the content of GO is 1.5wt%, the GO/HA composites sintered at 1150 ℃have bending strength of 81.5MPa and flexural toughness of 1.52MPa·m1/2.When the content of Ni Ti particles is 1.5 wt%, the Ni Ti/HA composites sintered at 1150 ℃have bending strength of 89.6MPa and flexural toughness of 1.65MPa·m1/2, Which is satisfied to the mechanical properties needs of artificial bone and can provide a new preparing method for artificial bone.