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In order to study the influence of structural parameters of metal casing on field strength, COMSOL finite element simulation software was used to simulate and analyze the size and distribution of electric field strength in multi-needle electrospinning process with metal casing. A composite spinning needle model was proposed, and the application of additional metal casing was extended. The results show that the maximum electric field strength of needle tip increases with the application ofjnaetal casing. When the thickness of needle tip is 0.6 mm, the CV value decreases from 7.5% to 3.2%. When the gap between needle and metal casing is 0.02 mm, the electric field strength is the most uniform, and the CV value is only 1.1%; the field strength is the largest when the casing height is consistent with the needle length. In addition, the electric field strength of spinning needle tip with composite structure increased by 82.9%, and PTFE coating on the inner side of the needle can effectively prevent the blockage of the needle; the seven-needle peripheral mounting casing of the composite structure has a field strength CV value of 3.23% smaller than 8.13% of that without metal casing, and the field strength of each needle tip is higher than the needle field strength without casing. [ABSTRACT FROM AUTHOR]

In order to develop the air filtration material with high and durable efficiency and low resistance, PVDF and PI electrets with different polarities were modified by doping SiO2 nanoparticles in different ratio via electrospinning technology. The performances of SiO2 doped PVDF and PI electrospun composite membranes, including surface morphology, fiber size, mechanical property, charging characteristics, and filtration behavior were tested and analyzed. The results showed that the charged SiO2/PVDF composite nanofiber membrane had higher initial surface potential than SiO2/PI membrane, decaying in a slower rate relative to the latter. Both the charging behavior and filtration performance of SiO2/PVDF composite nanofiber membrane increased first and then decreased as the component of SiO2 increased. When the mass ratio of SiO2/PVDF is 10/100, the SiO2/PVDF composite nanofiber membrane has the best charging behavior and filtration performance, the initial surface potential of the composite membrane was -8.7 kV, filtration efficiency and pressure drop were 99.328%@0.26 |Jim and 70 Pa respectively when the applied face speed was 32 L/min. The mechanical property, charging characteristics, and filtration behavior of electrospun SiO2 /PI composite membrane, however, declined dramatically with the addition of SiO2 nanoparticles increased. [ABSTRACT FROM AUTHOR]

The electrospun nanofiber membrane is prepared by dissolving polyethylene terephthlate (PET) chips in appropriate solvent, which is characterized with field emission scanning electron microscope (FE-SEM) in terms of fiber morphology, and the water proof, vapor permission and mechanical properties of the resultant nanofiber membrane are also tested. The results indicate that the nanofiber film with uniform diameter distribution and without beaded fibers could be obtained via using concentration greater than 15% of polymer solution, and the resulting electrospun PET nanofiber film possesses excellent hydrophobicity, good vapor permission and certain degree of hydrohead value. The mechanical strength of electrospun PET nanofiber membrane could be enhanced by increasing the thickness of the membrane, and then its hydrohead value increases, but the vapor transmission property of the membrane does not show significant change. [ABSTRACT FROM AUTHOR]

Self-designed reverse electric field electrospinning device and non-solution contact electrospinning device were employed to carry out a series of electrospinning experiments, and ANSYS finite element analysis software was used to simulate and analyze the field intensity distributions of the electrospinning setups, and thus to demonstrate the feasibility of non-solution contact electrostatic spinning technology theoretically and practically. The research results showed that, by using non-solution contact electrospinning technology, the nanofibers with narrow diameter distribution can also be obtained and no residual solvent, meanwhile the morphology of the nanofibers were same to that from conventional electrospinning technology, and the former has excellent safety property, which is expected to realize the production of nanofibers at industrial scale. [ABSTRACT FROM AUTHOR]