A Study On Preparation Of Continuous Nanofibers By Rotating Centrifugal Electrospinning

Electrospinning is an important method for preparing continuous nanofibers, which are highly promising for applications in a wide range of fields such as purification/filtration, photoelectric devices, battery separators, catalysis, tissue engineering, composite materials, and sensors. However, the efficiency(the yield of nanofibers) of traditional single nozzle electrospinning is very low, which greatly limits the industrial application of nanofibers. Therefore, one of the important issues is to increase the productivity of electrospinning. Aiming at increasing the nanofiber yield, this study established a rotating centrifugal electrospinning method by introducing centrifugal force into electrospinning process. In order to demonstrate the applicability of the rotating centrifugal electrospinning method, a variety of polymer and inorganic nanofibers were prepared. The main content and results are as follows:Based on the preparation of polyacrylonitrile(PAN) nanofibers, the effects of equipment parameters and process parameters on the morphology and yield of the nanofibers were investigated. The equipment parameters include nozzle diameter and nozzle number etc. while the process parameters include rotating speed, solution concentration, and electrospinning voltage etc. It was found that when keeping other parameters constant the productivity of the PAN nanofibers increases with increasing nozzle diameter. In terms of the effects of concentration and speed on nanofiber yield and morphology, an optimal nozzle diameter of 0.8 mm was determined. The output of the PAN nanofibers increases with the increase of nozzle number, but the morphology is not affected. Considering the effects of concentration and speed on nanofiber yield and morphology, an optimal number of nozzles of 25 was determined. At the rotating speed of 4200 rpm and PAN concentration of 20%, the maximum output is up to 186.12 g h-1, one thousand times higher than that of the conventional electrospinning.The applicability of the rotating centrifugal electrospinning method to preparing different nanofibers was investigated. It was proved that the method could produce different polymer nanofibers and different inorganic nanofibers such as carbon nanofibers, metal oxide nanofibers, and metal nanofibers after subsequent heat treatment. Polyethylene oxide(PEO) and polyvinyl pyrrolidone(PVP) fibers were prepared using N, N-dimethylformamide(DMF) and acetic acid as solvent, respectively. Meanwhile, the method was used to produce PAN nanofibers, precursor nanofibers of WO3, and precursor nanofibers of BN. After heat treatment, carbon, WO3, W, and BN nanofibers with uniform diameter were obtained.