Fabrication And Performance Research Of ?-TCP Bioceramic Powders For 3D Printing

As the third generation of biological materials,bioceramics are widely concerned in the medical field.Among them,?-TCP is the first choice for bio-ceramic materials with its excellent bioactivity,biodegradability and biocompatibility.There are many traditional preparation methods of biological ceramic material,including solid reaction process,hydro-thermal method,precipitation method,etc.,but these methods need a long period and expensive cost.They also can't be customized and have poor precision.With continuous development of molding technology,3D printing attracts wide attention for its simple operation,fast molding,high precision and individual design.This forming method is released from mold shape and structure.Any complex and hollow model can be manufactured in theory.Therefore,the combination of 3D printing and biomedical materials will become an inevitable trend.However,most 3D printing ceramics have rough surfaces,easy deformation and poor accuracy at present.In conclusion,it is necessary to prepare?-TCP bio-ceramic powders with good dispersity and flowability for 3D printing.This paper aimed at the shortness of 3D printing bioceramic,and conducted a systematic research on the fabrication and application performance of?-TCP bio-porous ceramics for 3D printing based on optic technology.Innovative results of the thesis were described as follows:1.Performance and modification of?-TCP raw materialsHigh-quality?-TCP powders with the improved forming performance were prepared by doping silica in solid state method for 3D ceramic printing.The different concentrations of silica were employed as the sintering additive to investigate the effect on the dispersity of?-TCP powders,microstructures and the densities of as-prepared ceramics.The sintering additive could reduce the agglomeration of raw powders in the progress of ballmilling,and weakly agglomerated powders were obtained which meant improvement of formability.Meanwhile,the average grain sizes decreased and densities of as-prepared?-TCP ceramics increased with the increasing of silica doping concentration.The sample with the best performance was achieved with 1.0 wt%SiO₂ when sintered at 1050°C for 8 h in air.Its average grain size and relative density were 0.57?m and 70.42%,respectively.2.Fabrication of?-TCP ceramic by spray drying for SLSMonodispersed and spherical?-TCP granules for 3D printing were prepared by spray drying with the surface modification of PVB.Modifier PVB attached to the particle surface to form the crosslinked network structure and keep them combine with each other into aggregates.The morphology,size,forming performance and crushing behavior of granules as well as the microstructure and density of as-fabricated?-TCP ceramics were used to optimize the PVB contents.Promising results could be expected that PVB contents were 1.0 wt.%and the average particle size of granules was 37.36 mm.The modified granules exhibited excellent forming performance with monodispersed and spherical aggregates for 3D printing.They could be completely crushed under 80 MPa without obvious inter-granules void.These granules with 1.0 wt.%PVB had defined strengths for ceramic forming.The good dispersity and flowability assured the high density and uniform porous structure of?-TCP ceramics,which were used as biological ceramic materials and completely met the standard for bone tissue engineering.3.Fabrication of?-TCP bio-porous ceramic for SLACeramic slurry with high solid content,low viscosity and high dispersity were fabricated by doping dispersant for SLA.Silane coupling agent KH-560 was used as dispersant to moisten the ceramic powders and photosensitive resins.Wettability between them was prominently improved,resulting to the improved performance of?-TCP ceramic.The optimized dispersant addition was 2.0 wt.%.?-TCP ceramic was fabricated with the sintering temperature of 1050 ^oC,holding time of 8 h to ensure?phase.The solid content was 48 wt.%,and the high quality ceramic with smoothness surface was obtained.The pores were evenly distributed.The porosity and density were 63.9%and 85.8%,respectively.