Research On The Forming Process And Application Of Non-solvent Induced Phase Separation 3D Printing Polymer

3D printing,as a research hotspot in the field of intelligent manufacturing,has the characteristics of near net shape,customization and so on.Based on the limitations of current polymer 3D printing technology,this paper proposes a non-solvent induced phase separation 3D printing process,which can realize high-precision and low-cost 3D printing of high temperature resistant material polyetherimide(PEI)at room temperature.This process can customize the macro porous structure by 3D printing,form micro porous by NIPS,and realize the molding of macro/micro composite porous structure.This kind of structure is widely used in bone tissue engineering scaffolds for medical implantation.The main research contents and results are as follows:(1)A gas assisted 3D printer with humidity control is built,the PEI of 3D printing at room temperature,high precision and low cost is realized,and polyetherimide(PEI)/N-methylpyrrolidone(NMP)printing paste is prepared,and the effects of printing speed,relative humidity of printing environment,printing layer and other process parameters on the molding quality are explored.The optimal process parameters:nozzle diameter 0.60mm,printing speed 10mm/s,extrusion pressure 0.4MPa,relative humidity 65-70%RH,layer height 0.48mm.Based on these parameters,PEI green body with good quality and high precision is formed.(2)The solvent removal process of PEI green body is explored.The results show that NMP in PEI green body can be completely removed after non-solvent phase separation and heating drying.The shrinkage of formed PEI products increases with the increase of heating and drying temperature.The faster the non-solvent replacement rate,the smaller the shrinkage rate,and vice versa.When water is the non-solvent,the shrinkage is 14.9%,and when ethanol is the non-solvent,the shrinkage is 20%.The slower the non-solvent displacement rate,the greater the tensile strength of the product.Based on this process,PEI macro/micro composite porous structure scaffolds are formed.The macro pore length is 500?550 ?m,the width is 470?510 ?m,and the porosity range from 57%to 61%.The micro pore size is mainly less than 20?m.the obtained pore size and porosity meet the requirements of bone tissue engineering scaffold,which is conducive to cell adhesion and growth.(3)HA/PEI bone tissue engineering scaffolds are formed by non-solvent induced phase separation 3D printing technology,which enhanced the mechanical properties and biocompatibility of macro/micro composite porous scaffolds.The macro pore,micro pore,hydrophilicity and mechanical properties are explored.The results showed that the hydrophilicity of HA/PEI composite is improved by adding HA.The macro pore size of HA/PEI porous scaffolds is 450?550 ?m,forming a mutually transparent pore structure,which meets the needs of bone tissue engineering scaffolds;the effect of HA ratio on the tensile strength shows a trend of first increasing and then decreasing;the elastic modulus of the products increases with the increase of HA ratio,and the mechanical properties of the products meet the requirements of human cancellous bone,which can be used in bone bearing.It is widely used in engineering support...