Development Of Curved Edge Dish-shaped Electrospinning Spinneret And Application For Preparing Air Filtration Mats

As the most efficient technnoloy to prepare micro-nano fibers,electrospinning technology is widely used in air filtration,biomedicine,clothing and other fields with great application value.However,the low efficiency in preparing fibers of the traditional single-needle electrospinning technology is difficult to meet the requirements of industrialization.Needleless electrospinning technology has greatly increased the fibrous productivity.In order to prepare finer fibers in high productivity,this paper proposes a new needleless curved-edge dish-shaped electrospinning spinneret,which can achieve the preparation of finer fibers in high productivity by increasing the electric field strength of the spinneret.In addition,the application of curved-edge dish-shaped spinneret in the preparation of air filtration mats is explored.The distribution of the electric field intensity at the spinning position has a great influence in electrospinning.Firstly,this paper analyzes the influence of the curvature of the spinneret on the electric field intensity distribution of the traditional round-sided dish-shaped spinneret.According to the one-dimensional potential well model of quantum mechanics,it is deduced that in the same electric field environment,the electric field intensity of the round-sided dish-shaped spinneret is positively correlated with the curvature of the spinneret.Using Ansys Maxwell software to perform finite element analysis on circular-edged dish-shaped spinneret with different curvatures,it is found that the simulation results are consistent with the above inferences.In order to eliminate the problem of the decrease of the fibrous productivity caused by the decrease of the spinneret circumference as the spinneret curvature increased,the circular contour of the traditional round-edged dish spinneret is changed to a curve divided by high curvature edges.The curved edge both increases the electric field intensity at the spinning positon of the spinneret and the number of spinning postions,and finally realizes the macro-preparation of electrospun fiber mats with finer fibers.Under the same test parameters,the diameter(240 nm)of the polyacrylonitrile(PAN)fiber prepared by the curved-edged dish-shaped spinneret is smaller than that of the traditional round-edged dish-shaped spinneret,and the productivity of the former is as high as 3.51 g/h,which is significantly larger than that of the round one(2.92 g/h).Furthermore,the influence of the curvature,the circumferential angle of the curved edge and process parameters on the electrospinning are studied.The results show that the electric field intensity at the edge of the spinneret gradually increases with the increase of the curvature of the spinnret's curved egde,but solutions trend to leak alone the slits between adjacent curved edges,causing the rapid deterioration of the spinning state to make the morphology of the prepared fiber bad,and the fibrous productivity decreases.With the decrease of the circumferential angle of the curved edge,the storage capacity of the spinning solution for the spinneret are significantly improved to make a good spinning performance of the spinneret.It is found that when the curvature and and the circumferential angle of the curved edge is 0.23 mm^-1 and 136°,the spinning performance of the spinneret is best.Then spnning parameters like solution concentration,working distance,voltage and speed of the drum were studied.Finally,by changing fibrous diameter and morphology of PAN fibers,fibrous mats with different porositie was prepared used the curved-edge dish-shaped electrospinning spinneret.Although the mat with fine fibers performs high filtration efficiency,but its density was too high causing a high value of filration resistance.Induced by tetradecyltrimethylammonium in high voltage,PAN fibers get fined and deposite unsteadily to form mats with very high porosity.Ensuring the filtration efficiency of the fiber mat,the filtration resistance reduces.When 30 wt%TTAC is added to the 10 wt%PAN solution,the filtration efficiency of the fiber mat is 99.49%,and the resistance is only 119.56 Pa,which also shows good antibacterial properties.