Electrospun Three-dimensional Nanofiber Membrane And Study On Its Filtering Performance

Traditional electrospun two-dimensional nanofiber membrane has small pore diameters,and the fibers are tightly packed.It shows a great air resistance when used in air filtration,and the mechanical properties of a single fiber membrane are poor.Its application is restricted to a great extent because of these problems.This article focused on the above issues,and the preparation of three-dimensional fluffy nanofibers with flexural pores and high porosity through the regulation of the electrospinning equipment was studied.Firstly,the conductivity and structure of the collecting substrate were changed.It was found that simply changing the conductivity of the collecting substrate did not have a significant effect on the bulkiness of the obtained nanofibers.Instead,when the polyester chemical fiber gauze with perforations(6 meshes/cm)and aramid weft knitted fabrics(23×30 in horizontal density×vertical density)were used as the collectors,the fibers had a fluffy feel.Compared with the aluminum foil,the filtration resistance decreased to a certain extent and the filtration efficiency did not decrease significantly.Especially for the knitted fabric,the filtration resistance of the prepared fiber material was reduced by 77.5 Pa comparing with that for the aluminum foil.Based on this,the collector's movement state was further changed,and the spring with smooth surface and excellent elasticity was used to collect the fibers and kept in a state of continuous motion.The filtration resistance of the fiber material was significantly reduced to only 25.5±0.1 Pa,but the filtration efficiency was low.The conductive yarns were added between the spring coils to optimize the structure and automate the remoting device.The relationship between the parameters concerning the spring's motion state and the filtration performance of the fiber material was analyzed.The filtration efficiency of the fiber material obtained after optimization was significantly improved,while the increase in filter resistance was small.To make the filtration efficiency of the fiber material met the application requirements,gradient design was performed on the surface,and a layer of finer nanofibers was electrospun on the surface using 8wt% of PAN polymer solution.And then they were combined with spunbonded and spunlaced nonwoven fabrics to form the “sandwich” structure to provide certain mechanical properties and comfort.The dust holding capacity of the filter material was increased.The obtained composite filter material had a good filtration performance with the filtration efficiency of 99.88±0.79%,and the filtration resistance was 85.0±0.2Pa,which satisfied the Chinese standard(GB2626-2006).It has the potential to be applied in the field of air filtration.