Study On The Toughening And Reinforcing Polylactic Acid Used In 3D Printing And Its Printing Process

Fused Deposition Modeling(FDM)is a very popular printing technology among 3D printing technologies,which mainly uses thermoplastic resin as its printing materials.Polylactic acid(PLA)is a kind of biodegradable material with excellent mechanical properties,which can be applied to FDM system.It is expected to replace Acrylonitrile butadiene styrene(ABS)as the most widely used FDM printing material,but the features of brittleness and poor thermostability limit its development.In this work,Poly(butyleneadipate-co-terephthalate)(PBAT)and Carbon Fiber(CF)have been used to modified PLA in order to toughening and reinforcing.PLA/PBAT and PLA/PBAT/CF composites were prepared to research their merchanical,thermodynamic and rheological properties in order to meet the requirements of FDM printing better.Main contents and results are showed as following.(1)PLA/PBAT blends were prepared by blending method.The results showed that PBAT could be effectively used to toughen PLA,the toughness of blends increased greatly with the increasing of PBAT.When the PBAT content is 30%,the elongation at break increased from PLA3.3% to 56.4%,the impact strength increased from 17.4J/m to 395.5J/m,but the addition of PBAT will weaken the mechanical strength of the blends.The addition of PBAT will lead to increased entanglement,so the viscosity of blends increased and the crystallization degree of PLA decreased.When the ratio of PLA/PBAT was fixed at 70/30,the addition of compatibilizer can improve the compatibility of the two component,it resulted out that when compatibilizer was 5phr the properties of blends were best.(2)As for the toughened blends(PLA/PBAT),the printing parameters such as printing temperature,degree of filling and accuracy infullence the printing produtions greatly.The properties of printing production would be better when the printing parameters were: temperature 220?,degree of filling 100% and accuracy 0.1mm,and it reached 75% of degree of injection production.In the meaning time,proper accury would help to get good apparent performance.(3)CF dispersed in the matrix uniformly without obvious agglomeration,it could improve the mechanical strength greatly especially the rigidity.When the content of CF was up to 20wt%,tensile and bending modulus reached 5600 MPa and 6200 MPa respectively.And the addition of CF could improve the melt strength and heat resistance of blends.(4)It resulted out that the PLA modified with CF need higher temperature to print compared with the toughening PLA.When printing temperature was 240?,the production had better mechanical properties than others and it could reach 60% degree of injection production.