Search

In order to obtain the best spiral needleless electrospinning structure parameters with uniform field strength distribution and high field strength value, the COMSOL finite element simulation software was used to simulate the field strength and distribution law in the needleless electrospinning process, and study the effect of length of coil, pith, radius, and radius of wire on electric field strength and its distribution. The results showed that for the spiral needleless electrospinning, the electric field intensity of the spinning head is generally high at the two ends and low at the middle. There are so-called "edge effects". In addition, increasing the coil length, coil diameter, and wire diameter will result in a gradual decrease in the field strength of the spinning head. Increasing the voltage, reducing the pitch and receiving distance will significantly increase the electric field intensity. When the coil length is 200 mm, the coil diameter is 60 mm, the pitch is 40 mm, and the wire diameter is 1 mm, the field strength of the spiral needleless electrospinning head is strong and evenly distributed, the average field strength is 1.81x10 V/m, and the field strength CV value is 7.08%. Then adding the gradually shrinking spiral coils to both ends of the spinning head as auxiliary electrodes, the effect of improving the uniformity of the electric field intensity distribution of the spinning head is the best, and the average field intensity obtained is 1.62x10 V/m, The field strength CV value is 2.53%, which effectively prevent the "edge effect". [ABSTRACT FROM AUTHOR]

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]