Research On Slip Mechanism In The Micro-triangle And Preparation Of Composite Nanaofiber By Centrifugal Spinning

Centrifugal spinning is a neoteric pattern of composite nanofiber preparation method.It uses centrifugal force as the main driving force to stretch a variety of spinning solutions through space jets to form composite nanofibers.The high-speed centrifugal composite spinning method is compared with traditional composite nanofiber preparation.This method has the advantages of simple structure principle,diverse spinnable materials,high preparation efficiency,low energy consumption and high fiber quality.Therefore,it has received extensive research and attention,and has broad application prospects.The slippage of the spinning solution in the high-speed centrifugal composite spinning jet movement is an inevitable phenomenon.The slippage can effectively improve the extrusion swelling phenomenon in the forming of the composite fiber,and it can also change the internal structure of the composite fiber so that the composite fiber has higher strength and tensile properties,so the study of the slippage rule of the spinning solution in the nozzle has a significant impact on the formation of composite nanofibers.This study area is called the microtriangle in the article.The factors affecting the motion and slippage of the two spinning liquid jets in the micro-triangular area are analyzed based on the principle of high-speed centrifugal spinning.The mathematical model is established for the three kinds of slips in the microtriangular area of the nozzle.The influence of speed and concentration on the slippage is analyzed.Finally,the polymer solutions of polyamide 6（PA6）and polyamide 66（PA66）were used as spinning raw materials to conduct high-speed centrifugal composite spinning experiments to explore the factors affecting the diameter distribution of composite nanofibers and the morphology of composite fibers.The main research contents of this paper are as follows:1.The principle of high-speed centrifugal spinning mechanism is studied,and high-speed centrifugal composite spinning is proposed on this basis,and the main process of preparing composite nanofibers by high-speed centrifugal composite spinning is analyzed.The preparation of composite nanofibers and the current research status of fiber slippage are introduced,and the influence of process parameters on fiber formation is analyzed based on the principle of high-speed centrifugal composite spinning.2.Complex fluid mechanics is the theoretical basis.Three mathematical models of slip in the micro-triangle of the nozzle are established to analyze the factors affecting the slip of the spinning solution in the micro-triangular area,such as motor speed,spinning solution concentration,etc.3.The rheological parameters of the polyamide spinning solution of different concentrations were measured by a rheometer,and ICEM was used for modeling and meshing.The model and rheological parameters were imported into Fluent to simulate the movement of the spinning solution in the micro-triangle of the nozzle.The distribution of pressure,velocity and turbulent kinetic energy in the micro-triangle of the nozzle under different rotation speeds and different concentrations are simulated,and the occurrence of slip phenomenon in the microtriangular area is verified by simulation.4.The high-speed centrifugal composite spinning device is used to prepare composite nanofibers.The premise of ensuring a single variable to change the motor speed,solution concentration,nozzle shape and other parameters to analyze the relationship between the morphology of the prepared polyamide composite nanofibers and the process parameters.The results show that when the motor speed is 2500 rpm,the nozzle is a straight nozzle and the diameter is 0.17 mm,and the collection distance is 40 cm,18wt.% of PA6 and PA66 spinning solution can be prepared and collected better PA composite nanofibers.Finally,the research work on micro-triangular slip of high-speed centrifugal composite spinning and PA composite nanofibers is summarized,the shortcomings and shortcomings in theory and experiment are analyzed,and the follow-up research directions and prospects are proposed.