Research On Artificial Bone 3D Printing Technology Based On HA-ZrO₂-PVA Composite

Artificial bone grafting is becoming an important way to repair bone defects in both natural and unnatural conditions.An ideal artificial bone implant requires an accurate shape of the defect site,an internal structure through which the pores penetrate,and mechanical properties and biocompatibility similar to those of natural bone.As an emerging manufacturing technology,3D printing technology has the advantages that traditional artificial bone manufacturing methods do not have,such as the ability to machine complex external contours and internal structures.In order to provide a solution from material selection to printing process to performance testing,this paper aims to manufacture artificial bones with mechanical properties and biological properties that meet the actual requirements through 3D printing technology,through research on new composite materials and manufacturing processes.The influence of relevant process parameters on the forming process has obtained a new scheme for the manufacture of artificial bone implants.The main work of the thesis is as follows:(1)A new artificial bone implant composite preparation scheme was proposed:the hydroxyapatite(HA)was toughened by zirconium dioxide(ZrO2)and bonded with polyvinyl alcohol(PVA)solution.The experimental preliminary verification of ZrO2 composite The effect of improving the mechanical properties of the material.According to the theoretical calculation of fluid mechanics,it is determined that the new composite material belongs to the power law fluid and appears as laminar flow during the flow process.The viscometer test shows that the relationship between the viscosity of the composite material and the shear rate is negatively correlated,which is the continuous printing of the subsequent artificial bone implant.Provides relevant reference.(2)The theoretical model of extrusion flow,extrusion speed,line width and porosity was established by the knowledge of fluid mechanics.The flow process of composite slurry was simulated by FLUENT software.The simulation results verified the preparation of artificial bone graft by 3D printing technology.Feasibility of entry and guidance of theoretical models.(3)In order to obtain the best process parameters,the same experiment was carried out for each group of preparation schemes:the influence of the pressure change on the extrusion flow rate and the extrusion speed under different nozzle internal diameters;under different pressure values,the nozzle movement speed changed the line width of the extruded material.Influence;the effect of different line spacing on the porosity;the effect of different temperatures on the forming size of artificial bone samples.Through the above experiments,the optimal pressure value range of 1-3bar,the best line spacing of 0.8-1.5mm,the optimal nozzle moving speed range of 8-10mm/s,and the optimal heating temperature of 30 degrees Celsius were determined.(4)The data of mechanical properties of artificial bone samples under different ratios were tested.The data showed that with the increase of ZrO2 content,the compressive strength of artificial bone samples increased from 5MP to 17MPa,and the corresponding elastic modulus increased from 52MPa to 174MPa,which verified ZrO2.Toughening effect and the program as a mechanical performance of artificial bone implants.Through experiments,it is found that the honeycomb internal structure has a significant effect on the improvement of mechanical properties.The compressive strength of the artificial bone implant can be increased to 25 MPa and the elastic modulus is increased to 259 MPa.In vitro decomposition experiments and cell culture tests were performed on the printed artificial bone samples to obtain the biocompatibility performance of each group of samples.In the in vitro degradation experiment,each group of samples obtained an increase of 2%-4%by weight after 14 days,showing a comparison.Good apatite layer deposition ability.In the cytotoxicity experiment,the cytotoxicity level of the sample of the second and third groups was evaluated as 0,and the fourth group was evaluated as the level of cytotoxicity.The cells showed good growth under microscope observation.