Preparation And Application Of Porous PLA Fibers With Hollow Sturcture

During the preparation,transportation,and use of diesel fuel,impurities and water are often mixed in.These substances presented in diesel fuel can clog the fuel engine and cause potential failure of mechanical components such as fuel pumps and injectors.Thus,the impurities and water in diesel must be effectively removed.In view of the shortcomings of ordinary fiber membranes in oil/water treatment,this study uses 2 wt%PVA as core spinning solution,and 8 wt%PLA as shell spinning solution to prepare PLA fibers with hollow and lotus root-like structures by coaxial electrostatic spinning.When compared with ordinary fiber membranes,the prepared PLA fiber membrane has the advantages of large surface area,high porosity,excellent adsorption and selected filtration,light mass,rich hole structure,and better hole connectivity.It can be used for efficient diesel micro moisture treatment without causing secondary pollutionsFirstly,we investigate the formation mechanism of porous and hollow structures of the fibers,and analyze the effects of spinning process parameters,including core/shell flow rate ratio,voltage,and receiving distance,on the morphology and hollow proportion of the fibers quantitatively.The results show that the process parameters have little effect on the morphological characteristics such as diameter,surface porosity,cross-section pattern,and cross-section porosity,but influence the hollow proportion significantly.When PVA/PLA flow rate ration is 0.3:0.9 mL/h,voltage is 19 kV,and receiving distance is 6 cm,the hollow proportion reaches the maximum which is 76.32%.Secondly,3D models of the PLA fibers with maximum hollow proportion are established based on quantitative analysis of the morphological characteristics of the fibers including the diameter of pores on the surface,inner and outer diameters of the cross section,surface porosity and cross-section porosity.At last,we investigate the water/oil contact angles and water/oil sorption capacities of the fibers with different structures.The results show that the fibers with lotus-root-like structures are hydrophobic and oleophilic;their oil sorption capacities are 2.5 times that of the fibers with hollow structures,while water sorption capacities are only one-third of the latter.Because the fibers with hollow structures have low oil sorption capacities and separation efficiency as high as 98.67%,they are more suitable for diesel micro moisture treatment.