The Research On The PS And Its Composite Powders Prepared By Selective Laser Sintering

The selective laser sintering(SLS)is a very important rapid prototyping(RP)technology,which forms three-dimensional solid parts through the computer software aided hierarchical processing to selective sintering separate section.And the polystyrene(PS)as a polymer materials that widely used in the field of SLS also has a important research value.This paper based on the nylon12(PA12)and multi-walled carbon nanotubes(MWCNTs)as an organic fillers added to the PS matrix materials,two kinds of composite powders be prepared.Then,the effect is analysed that the sintering parameter influences on the formability of PS/PA12 composites be prepared by SLS,the contrast of the mechanical properties and the dimensional accuracy between PS/PA12 composites and pure PS is researched,and the cause of secondary sintering is analysed.Meanwhile,the effect is analysed that MWCNTs influences on the properties of PS/MWCNTs composites.It still have many problems that need to be solved for PS/MWCNTs composites,therefore,the research has a important and practical singnificance.Different components of nylon 12(PA12)and polystyrene(PS)composite powder were prepared by mechanical mixing method and it was molded by selective laser sintering(SLS).The effect of the PA12 / PS composite powder composition on the mechanical property,dimensional accuracy and fractured microcosmic morphologies of the sintered specimens were investigated.The results show that because of the difference between PS and PA12 is large,it cause the secondary sintering problem in the SLS process.And PA12 is crystalline polymer,it will have great negative influcence to the dimensional accuracy of the PS/PA12 composite because of its crystalline polamer in the SLS process.But,the mechanical property of PS/PA12 composite is also improved.Multi-walled carbon nanotubes(MWCNTs)were dispersed in the polystyrene powder by mechanical mixing to prepare a composite(PS/MWCNTs)and used in the selective laser sintering(SLS)process.Infrared spectroscopy,Raman spectroscopy,X-ray diffraction and dynamic mechanical analysis were used to analyse the structural and mechanical propertirs of the composite.The mechanical property,dimensional accuracy and fractured microcosmic morphologies of the specimens of PS/MWCNTs and PS were investigated.The result shows that the tensile strength and breaking elongation rate of the specimens of PS/MWCNTs compared with PS specimens are increased by 32.6%,7.7% respectively and the dimensional accuracy compared to the pure PS were also increased.The result shows that MWCNTs as a reinforcing material has a great development prospect in the fields of SLS.