Process Parameters And Properties Researches Of Nafion Nanofibers Fabricated By Electrospinning

In recent years, Nafion nanofibers have been exerted unique advantages gradually. Compared to other Nafion products, such as, beads, solution and membrane, Nafion nanofibers have many merits including high specific surface area, high porosity, enhanced conductivity and so on. Electrospinning is a simple and effective method to fabricate Nafion nanofibers. Several researchers have done lots of work on fabrication of Nafion nanofibers by electrospinning. However, most of them adopt Nafion solution as experimental material. Nafion beads are more convenience to transport and reserve than other forms. In this study, the beads are used. Moreover, the price of Nafion beads is lower than Nafion solution. During the electrospinning experiment, the process parameters are discussed by means of orthogonal experimental design method, including the content of carrier polymer, that is, the quantity of PEO in solution, flow rate of spinning solution, speed of roller collector and the distance between spinning nozzle and roller. There are three levels of each parameter. As a result, the primary and secondary parameters and the best level affecting on nanofibers diameter are achieved. The four considered factors influencing the average nanofiber diameter are in the following order:flow rate> distance between the syringe needle and roller collector> roller rotation speed> carrier polymer content. The optimal conditions in this study are 0.04 g carrier polymer content,23 cm distance between the syringe needle and roller collector,0.1 mL·h-1 flow rate, and 180 r·min-1 roller rotation speed. These conditions are further used to optimize the fiber diameter. The resulting nanofibers have a diameter of approximately 150 nm, indicating that our proposed orthogonal design method is suitable and advantageous. What’s more, the content of Nafion in nanofibers is up to 98%. The obtained Nafion nanofibers membrane is taken to do the conductivity test. The result shows that the conductivity of Nafion nanofibers membrane is 6 times higher than commercial Nafion 115 film at the condition of room temperature.To enhance productivity of Nafion nanofibers, centrifugal electrospinning is utilized in this study. Because of late development of centrifugal electrospinning, the spinning mechanism and process parameters need to be studied in-depth. In this paper, PVP is used firstly as raw material to explore the influence of different voltage and speed affecting on nanofibers diameter and performance, jet path, and nanofibers productivity before the fabrication of Nafion nanofibers. At last, Nafion nanofibers are prepared by centrifugal electrospinning successfully. But there are still a plenty of problems existed such as high viscosity of Nafion/carrier polymer solution, over flow rate which causes so many difficulties in spinning process. It is sincere to hope that the later researchers could do deeper research on the apparatus and parameters of centrifugal electrospinning.