Preperation Of PC And Its Composite Materials Filament And Study On Fused Deposition Modeling

Polycarbonate(PC),as an engineering plastic,possesses good mechanical properties,heat resistance and dielectric properties.However,PC is sensitive to the notch,has high processing temperature,and is expensive in price,so that the application range is limited.Therefore,PC is usually modified in engineering to improve its comprehensive performance and reduce production costs,to broaden its application fields.ABS has excellent impact resistance,heat resistance,low temperature resistance,excellent electrical properties,and easy processing characteristics.In this paper,PC and ABS were blended to prepare PC/ABS alloy.The application feasibility of PC/ABS alloy on FDM was discussed,aiming at broadening the range of FDM application materials.Firstly,this paper discussed the relationship between the apparent viscosity of PC and the shear rate and melting temperature.It is determined that the suitable processing temperature of the PC should not be lower than 240°C.In the blending and extrusion process of PC and ABS,the extrusion temperature and screw speed can be appropriately increased to promote the effective compatibility between PC and ABS.Then,the optimum proportion of PC and ABS for preparing PC/ABS alloy were studied.When the mass ratio of PC and ABS is PC:ABS=70:30,the comprehensive performance of PC/ABS alloy is best.The tensile strength is 63.86 MPa,bending strength is 77.31 MPa,notch impact strength is 14.54 KJ/m~2,the mechanical properties are optimum values.The melt flow rate is 25.44 g/cm~3,the melt flowability is optimized.When the mass fraction of PC is 70%,the thermal decomposition temperature is higher and the heat resistance is better.In order to further promote the compatibility bewteen PC and ABS and improve the comprehensive performance of PC/ABS alloy,three kinds of modifiers of ABS-g-MAH,MBS and OMMT were used to compatibilize PC/ABS alloy,and the mechanical properties,thermal properties,melt flow rate,thermogravimetric properties,filament formability and FDM printability were discussed.The experimental results show that when the mass fraction of ABS-g-MAH is 6%,the notch impact strength of PC/ABS alloy is 33.92 KJ/m~2,which is more than twice as that of pure PC/ABS alloy,the impact toughness is greatly enhanced,and other mechanical properties and thermal performance are virtually unaffected.When the mass fraction of MBS is 6%,the toughness of PC/ABS alloy is best,however,when the mass fraction of MBS is 7%,the strength of the alloy is highest.When MBS is added,the flowability of the alloy melt is slightly lowered,but the vicat softening temperature is increaseed and the heat resistance is improved.The OMMT is obtained by modifying MMT with octadecyl trimethyl ammonium bromide.After modification,the OMMT is analyzed by X-ray diffraction analysis,and the interlayer spacing is 2.04 nm,which is0.08 nm larger than that of MMT.When the OMMT mass fraction is 3%,the tensile strength of PC/ABS alloy is increased by 5.25%,the flexural strength is increased by4.64%,the notch impact strength is increased by 39.58%,and the vicat softening point is increased by 6?,but the melt flow rate is slightly decreased.In the DSC analysis and DMA analysis of the alloys,it is found that there were two Glass transition temperature in the three alloys,which are phase-separated at the microscopic level,and the thermal motion of the PC and ABS molecular chains are not affected by each other.The single-screw extrusion drawing of the three modified agent compatibilized PC/ABS alloys was carried out to discuss the filament formability of the alloy and the applicability of FDM.The experimental results show that the filament of PC/ABS/ABS-g-MAH alloy has good strength and is suitable for FDM molding,but the diameter stability is slightly worse than pure PC/ABS alloy.PC/ABS/MBS alloy filament has excellent dimensional stability and good strength,it's an excellent material for FDM.When the OMMT content is less than 3%,the PC/ABS/OMMT alloy filament has better forming effectiveness and the filament material performance is better.After comprehensive analysis,the PC/ABS alloy were choosed for FDM printing when the mass fraction of ABS-g-MAH is 6%,the mass fraction of MBS is 7%and the mass fraction of OMMT is 3%respectively.In the printing experiment section,this paper firstly discussed the suitable printing parameters of FDM for PC.When the nozzle temperature is 240?,the plateform temperature is 110?,the printing speed is 30 mm/s,and the printing layer thickness is0.2 mm,the printing samples of PC present best mechanical properties.Then,the three kinds of PC/ABS alloys were printed with XY orientation,XZ orientation,and ZX orientation in FDM printer respectively.The mechanical properties of the PC/ABS/ABS-g-MAH alloy printed samples are generally good,and the PC/ABS/MBS alloy printed samples also have good mechanical properties while maintaining better toughness,however the properties of PC/ABS/OMMT alloy printed samples are little poor.In addition,regardless of the alloy filament,the samples printed with ZX orientation has the worst mechanical properties.The tensile strength and bending strength of the samples printed with XY orientation are better,and the notched impact strength of the samples printed with XZ orientation is better.