The Filtration Performance Of The Electrospuning Nanofiber Mats

At present, environmental issues continue to the hot, air filtration industry was given more and more people’s attention. With the high surface area, high porosity and physicochemical properties, nano-materials are very suitable for air filtration. The researches and applications in this field have also been considerable progress. As an important forming method of nanofibers, electrospinning can effectively control the micro- and macro-structure of nanomaterials, become a focus research about nanofiber air filter material. In this paper, the work can be divided into three steps: first, we did research for the electrospinning process to obtain the desired structure and morphology of the fiber by adjusting the parameters. Then though the filtration test, we try to understand the effect of fiber morphology and filtration conditions on the material filtration properties. Second, the materials and structure of collector fabric on filter performance was studied, and compare the characteristics of the actual product masks and nanofiber filter material. In order to achieve the purpose of high efficiency and low resistance, the filtration performance impact of the three-dimensional structure of nanomaterials was studied, and mixed, gradient structure or other measures to improve nanomaterials packing state, in order to find an appropriate way to improve filtering quality.Electrospinning parameters(voltage, collector distance, the molecular weight distribution, the solvent and concentration, etc.) have a great influence on the nanofiber microstructure. The influence of the parameters was also difference for different electrospinning system. For example, with lower viscosity Polymer A solution, electrospinning will arise part of the crude fiber in the case of high voltage, thereby forming a wide distribution of fiber diameter nanofiber mat. Reducing the collector distance made more disordered fibrous distribution. Polymer molecular weight distribution and electrospinning nanofibers diameter distribution were in harmony. The study found the three-dimensional structure of nanofibers accumulation was the key to coordination of filtration efficiency and air resistance.Filtration test conditions may make the material show different filter properties. For Polymer B nanofiber filtration test, the sample of lower voltage had high filtration efficiency and air resistance in Na Cl particles, but oily tests reflected the opposite result. After analysis of large amounts of test data, there was a direct relationship between flow and air resistance, air resistance increases with flow rate. And the fluffy degree of the filtering medium was the key to air resistance. Not only would the size of the particles but also the nature of the filter affect the flow of filtration efficiency.Folding and stacking can be very good to retain the microscopic structure of the materials, thus ensuring the filtering properties. The filtration efficiency of nanofiber layer mask was 25% larger than PFE, and with the test time rapid increase, filtration efficiency tends to limit, air resistance also showed straight up.Matching up the coarser fibrous and Polymer A nanofiber can be obtained wider mat, and achieved with proper high filtration efficiency with low air resistance. The appropriate proportions of the overall hybrid filtration got hybrid-fiber distribution, improving material strength and filtration properties. Mixed with fiberglass filter helped to improve performance, but adding too much will reduce the improved effect. As a whole, gradients structure and mixed material could enhance the overall performance of the filter, and there was an optimum range.