Fabrication And Characterization Of Electrospun Poly(M-Phenyleneisophthalamide)/Polyacrylonitrile Blend Nanofibers Membrane

Now the air pollution in our country become more serious. Conventional fiber filtration material can not satisfy people’s demands in fine filter field because of its filtering accuracy. Recently, nanofibers are wildly used as filter materials due to its great surface area, porosity and high filtration precision. In this paper, electrospinning was used to fabricating Poly(m-phenylene isophthalamide)(PMIA)/Polyacrylonitrile(PAN) blend nanofibers.Firstly, we researched the effect of cosolvent in the process of dissolving the fibers.Besides, we also used three solvents that of DMAc, DMF and NMP to study the difference.The results showed that without the anhydrous LiCl, fibers can only limited swelling, we can get the highest efficiency with 2wt% of anhydrous LiCl. Among the three kinds of solution, the nanometer fiber membrane formed in the DMAc has the lowest surface tension. Besides it has the greatest crystallinity and mechanical properties.Secondly, we studied the influence of the voltage, receiving distance, discharge speed,rotating speed,ratio and the mass fractionn the fiber morphology. The result showed that ratio and mass fraction of solution had great influence on fiber morphology. The average fiber diameter decreases with the increase of voltage. The average diameter of fiber increased with the increase of receiving distance, discharge speed and the rotating speed.The best spinning parameters as follow: mass fraction 10wt%, voltage 26 kv, receiving distance 12 cm, and discharge speed 0.3ml/h.Thirdly, five different ratios of PMIA/PAN formic solution were prepared. The rheological properties, surface tension and conductivity of solution were studied.Nanofiber membrane was prepared by the method of electrospinning. The molecular structure, aggregation structure, thermal property and mechanical property of nanofibers membrane were researched. The results showed that the mixed solution present non-newtonian fluid mixture model and two components mixture decreased thecrystallinity of materials.Finally, we used different spinning process parameters to fabricate several micro nano membrane/nonwovens composite material with different diameter and different surface density. Then we tested the filtration performance of composite material and using the image method to analyze the membrane surface porosity. The results showed that the voltage, receiving distance, velocity and drum rotational speed all will influence the quality of the micro/nano fiber membrane factor. Among them, the influence of velocity is the most complex, because with the increase of flow velocity, the average diameter of the fiber membrane will increased gradually. Besides, the surface density will increased gradually too, which makes the quality factor appear larger fluctuation.