Study On Performance Modification Of Tricalcium Silicate Ceramic Composites And Its Additive Manufacturing

With the advancement of the clinical level of medicine,the increasing cure rate of bone trauma and bone tumors has led to increasing demand for artificial bone implants.The preparation of artificial bone scaffolds with excellent mechanical and biological properties has become bone repair and manufacturing research hotspots.Tricalcium silicate bioceramics can degrade and deposit granular apatite in a physiological environment.Hydroxyapatite has similar properties to human bone,which have good biocompatibility;silicon ions and calcium ions are released during the degradation of tricalcium silicate,which can promote the proliferation of bone cells,and the porous structure produced at the same time facilitates the proliferation and attachment of bone cells.However,tricalcium silicate has poor mechanical properties,is easy to break and break,and has a fast hydration rate.It can not be operated in an urgent time for complex molding,which limits its application in artificial bone implants.Here,based on adjusting the performance of the composite ceramics of tricalcium silicate as the base material and combining 3D printing technology,the performance control of mechanical properties,biological properties,printability,slurry flow properties,and degradation properties of tricalcium silicate composite ceramic materials is realized.The performance regulation and additive manufacturing research of tricalcium silicate composite ceramic materials were exhibited,and the realization of high-precision and complex molding of tricalcium silicate,which is difficult to be formed,is detailed.The specific research contents and results are as follows:Tricalcium silicate/silica gel composite ceramic slurry was prepared,and the effect of hydroxypropyl methylcellulose(HPMC)content on the agglomeration of ultrafine powder was studied.When the HPMC content was greater than 1.0 wt%,most of the powder agglomeration disappeared,and it could be carried out high-precision molding;The effect of silica gel particles on the printable time of tricalcium silicate composite paste was studied.The printable time of 5.0 wt% silica gel / 95.0 wt% tricalcium silicate composite slurry is 143 ± 17 min,which meets the time requirements for complex molding.The pressure resistance of the sample is 20.2MPa.At the same time,it reduces the degradation rate of tricalcium silicate in vitro and has a good ability to induce hydroxyapatite deposition.The prepared tricalcium silicate/silica gel composite ceramic slurry regulates the comprehensive performance given the difficulty of 3D printing of tricalcium silicate,and has good biocompatibility and mechanical properties.This provides research ideas for the fabrication of artificial bone scaffolds that are difficult to form complex bioceramic powder materials.Aiming at the disadvantages of tricalcium silicate with poor mechanical properties and difficult application,the mechanical properties,microstructure,and biological properties of tricalcium silicate/polyetherimide composite ceramics were improved through polyetherimide(PEI)added and low-temperature-assisted sintering.The PEI particles were melted by assisted sintering at 340 ° C for 2 hours to repair the internal defects of the tricalcium silicate ceramic and enhance the internal structural density.The mechanism of PEI on the mechanical properties of C3 S ceramics was studied.When the PEI content was 10wt%,the compressive strength of the composite ceramic samples after sintering was 29.6MPa,which improved the strength by 55.1%.The bending strength is 7.55 MPa,which is not significantly different from the original sample.The flow performance has been greatly improved,and the flow performance at 40 minutes is still comparable to the initial flow performance of C3 S.The composite ceramic scaffold was manufactured by 3D printing,and it was verified that the low-temperature-assisted sintering of the C3 S / PEI sample can significantly improve the biocompatibility of the sample,and at the same time,it has good cell adsorption effect.The low-temperature-assisted sintering C3 S / PEI regulates the comprehensive mechanical properties of the sample,improves the internal defects of the sample,and improves the biological performance.It provides an experimental basis and theoretical basis for the modification and post-treatment of bioceramic composite materials.Polyetherimide(PEI)can significantly improve and regulate the comprehensive properties of tricalcium silicate,and has great potential in the ceramic artificial bone additive manufacturing.The influence of process parameters of pneumatic injection additive manufacturing of C3 S / 10PEI(90 wt% C3 S,10 wt% PEI)composite ceramic slurry on molding quality was studied and optimized.Orthogonal experiments revealed the extrusion swelling effect of C3 S / 10 PEI composite ceramic paste under different printing parameters(nozzle diameter,extrusion pressure,nozzle type),and explored the print layer height on the deposition line width and deposition line height.The influence mechanism of different nozzle diameters on the print layer height is obtained.The influence of the pressure advance time on the deposition of the slurry during the printing process and the influence of the nozzle diameter on the cumulative number of layers(height)of the deposition line were studied.The system summarizes the process parameters that affect the pneumatic injection additive manufacturing of C3 S / 10 PEI composite slurry,and provides the theoretical basis and experimental basis for the realization of high-precision molding of C3 S / 10 PEI composite ceramic slurry complex artificial bone scaffolds.