Fabrication And Properties Of Haracterization Of Polycaprolactone Based Materials For 3D Printing And Membranes For PM2.5 Filtration

Environmental pollution has aroused public concern,especially the white pollution and haze problems.It’s a huge threat to public health.It’s important to develop biodegradable polymers.Polycaprolactone-based materials for 3D printing were prepared by polylactic acid modification.The rheological properties and thermal properties of polycaprolactone-based composites were studied.Furthermore,aiming at PM2.5 filtration,the polycaprolactone nanofiber membrane was fabication by electrospinning method.The filtration efficiency of PM2.5 and air permeability were evaluated.The development of polycaprolactone-based materials can not only solve the waste pollution,but also open up new materials application pathway.PCL was printed by fused deposition modeling(FDM)technology.When the printed temperature is lower than 190℃,PCL filament twined around the 3D printer’s feed gear.While the temperature is higher than 190℃,the melted PCL extruded from the nozzle was difficult to rapidly solidify and deposit on the printing platform,resulting in many defects.Capillary rheometer test showed that the viscosity of PCL is much higher than polylactic aci(PLA),and the extrusion pressure is high up to 48Mpa,wheras the yield strength of PCLwas 15Mpa.DSC test showed that the melting temperature of PCL was 56.5℃ and the crystallization temperature of PCL was 18℃.Thus,extruded at high temperature,PCL filament was solidified too slower s to rapidly deposit on the printing platform.The PCL/PLA composites for 3D printing were prepared by melt blending.The effects of PLA content on the rheological properties,thermal properties and crystallinity of PCL were studied by capillary rheometer and DSC.PLA molecules played as plasticizer,which increased the space between PCL molecular chains,and reduced the entanglement among PCL molecular chains,thus resulting in the viscosity and extrusion pressure of PCL decreasing.In addition,the addition of PLA also improved the mechanical properties,thereby reducing the printing temperature of PCL.In the other hand,glass transition temperature of PLA was higher than the melting point of PCL.In the cooling process,PAL played the role of nucleating agent to improve the crystallization temperature and crystallization rate of PCL,so that PCL could be quickly deposited on the printing platform deposition.The PCL/PLA composites with 20 phr showed better comprehensive performance than PCL/PLA composites with other PLA content,and its printing temperature was 130℃,which was much lower than the commercially available 3D printing materials.Finally,the cytotoxicity test showed that suffered from the high temperature melt blending process,PCL and PLA did not decompose to produce toxic substances.Haze was a serious threat to people’s health.The effect of electrospinning parameters on the pore size and porosity of nanofiber membranes was studied by electrospinning method.The nanofiber membranes with high PM2.5 filtration efficiency and good air permeability were obtained.The pore size of the fiber membrane decreased as the electrospinning time increased,yet the PM2.5 filtration efficiency and the air resistance would increase,which resulted in the air permeability and the light transmittance decreasing.The nanofiber membranes obtained by electrospinning 15min possessed the best property,which the filtration efficiency of PM2.5 was up to 98%and the air resistance was 26Pa.In addition,PCL nanofiber membrane could be degraded,did not produce secondary pollution.PCL based biodegradable materials for 3D printing and membranes for PM2.5 filament were prepared.The integrated performance was excellent and environment friendly.