Simulation And Experimental Exploration Of Polymer Melt Centrifugal Electrospinning Process

Centrifugal electrospinning is a method for preparing micro-nano fibers.The centrifugal force generated by the high-speed rotation of the centrifugal disc and the electric field force generated by the high-voltage electric field are used to stretch the polymer solution or melt to form fibers.During the spinning process,the coupling effect of centrifugal force and electric field force on the droplet reduces the diameter of the fiber,and the obtained fiber has excellent performance,showing excellent orientation in both macroscopic and microscopic aspects.A new preparation method is provided.Therefore,it is necessary to deeply explore the flow and fiberforming process of centrifugal electrospinning.In order to solve the above problems,this paper firstly establishes a two-phase fluid simulation model of melt and air.By analyzing the change process of polymer melt under the action of electric field force,the Taylor cone and jet formation process are simulated,and the Taylor cone and Visualization of the entire process of fibrillation.The research results show that when the melt falls,due to its own charge,the electric field strength in the spinning area increases;the melt fiber exhibits a state where the internal force is smaller than the external force,the fiber stretches from the inside,and the external melt "collapses" to the inside,the diameter of the fiber decreases;as the voltage increases,the cone surface of the Taylor cone changes from convex to concave,and the triangle of the Taylor cone gradually decreases,and the melt can form a jet faster,this is the same as the experimental study results;the melt flow rate is too fast,the effect of electric field force on fiber thinning is completely invalid.The second is to simulate the electric field distribution of the centrifugal electrospinning device,the flow characteristics of the melt in the flow channel of the centrifugal disc,and the air flow field around the centrifugal disc when it rotates at high speed.The research results show that the electric field strength of the needle type spinneret and the differential type is basically the same at a distance of 5 mm from the outlet;after using the circumferentially distributed electrode plate instead of the annular electrode plate,the circumferential electric field strength is significantly improved,which is conducive to the orderly arrangement of fibers..The flow velocity of the melt in the runner is basically proportional to the length of the runner,and proportional to the square of the rotational speed of the centrifugal disc,indicating that increasing the rotational speed is more reasonable than increasing the length of the runner.When the centrifugal disc rotates at high speed,vortices appear in the axial direction of the air field,and two air fields flow in opposite directions in the circumferential direction,causing the fibers to be disorderly entangled and sheared laterally,which affects the formation of long fibers..Finally,a melt centrifugal electrospinning equipment was designed and built by ourselves.Isomalt fibers were prepared by this equipment under orthogonal experimental conditions.Water retention was studied.The results show that the most influential factor on the diameter of isomalt fiber is the rotation speed of the centrifugal disc,followed by the temperature of the centrifugal disc and the spinning voltage;temperature.The most influential factor on the moisture absorption rate of the fiber membrane is the fiber diameter;the most influential factor on the moisture retention rate of the fiber is the fiber standard deviation;the experimental results verify the prediction of the fiber distribution and stress in the simulation.In summary,this paper uses simulation methods to explore the processes and mechanisms of melt flow,Taylor cone formation,fiber thinning,and fiber orderly collection during centrifugal electrospinning;and isomalt fibers were prepared according to the simulation results.And tested it;it provides theoretical guidance for the further development of centrifugal electrospinning,which is of great significance to the industrialization of centrifugal electrospinning.