Study On Rheological Behavior Of Polyetheretherketone And 3D Molding Processing

Polyetheretherketone(PEEK)is a linear semi-crystalline polymer with excellent properties and important applications.PEEK has excellent properties due to its regular molecular structure,such as heat resistance,corrosion resistance,radiation resistance,wear resistance and damage resistance,as well as flame retardancy,creep resistance,biocompatibility,high mechanical properties and easy processing.PEEK has been successfully used in aerospace,mechanical manufacturing,electronic communications,medical equipment,transportation and petrochemical industries.At present,the most usual processing method of PEEK is melting extrusion.However,due to the poor mobility of the molecular chain,the processing of PEEK is difficult with the high melt viscosity and the poor rheological behavior.Silicone resins have been shown to improve the processing properties of polymers,but it hasn't been reported whether silicone resins can improve the processing properties of PEEK.Additive Manufacturing(AM)is an emerging processing method for thermoplastic polymers.Compared with the traditional melt processing method,AM does not need the build molds,which greatly shortens the production cycle and reduces production costs.It is also a fast-growing manufacturing technology.Fused deposition modeling(FDM)has many advantages,such as simple operation and maintain,simple handling after parts which is widely used in many fields.PEEK has been proven to be processed by FDM,but the PEEK parts obtained by this method have poor mechanical properties,which limits their application in FDM molding.The main research content of this thesis are as follows:1.Two hyperbranched silicone resins,polymethylsilsesquioxane(PMSQ)and polyvinylsilsesquioxane(PVSQ),were prepared by an optimized green hydrolysis method.The two silicones were characterized by GPC,29Si NMP,FT-IR and TGA,which proved that we obtained the required hyperbranched silicone with good solubility.The prepared silicone resin is melt-blended with PEEK pellets to obtain PEEK-M and PEEK-V two composite materials.Further,the two composites were characterized and analyzed by SEM,ART-FTIR,rheological test,crystallinity test,DSC,TGA and mechanical test,which proved that the addition of two hyperbranched silicone resins can reduce the viscosity of PEEK during processing to improve processing performance.At the same time,the method is simple in operation,low in cost and environmentally friendly,and broadens the application range of PEEK in the traditional melt processing technology.2.An optimum printing parameter for printing PEEK in matching printers was studied,which was determined from three aspects:printing temperature/layer thickness/raster angle.Then,the existing FDM 3D printing device is modified,and a laser is applied to preheat the flattening and annealing of the printing base layer,thereby greatly improving the mechanical strength of the printed part.Under the laser assisting,the highest tensile strength of the printed parts can reach 58 MPa.The highest tensile strength of the printed parts after annealing can reach 70 MPa,which is 74%of the bulk strength of PEEK.Finally,the reasons for the enhanced mechanical properties of PEEK parts were demonstrated and analyzed.This provides a new way for 3D processing of polymers with high temperature materials.