Multi-Layered, Corona Charged Melt Blown Nonwovens as High Performance PM_0.3 Air Filters

Particulate matter (PM) and airborne viruses bring adverse influence on human health. As the most feasible way to prevent inhalation of these pollutants, face masks with excellent filtration efficiency and low press drop are in urgent demand. In this study, we report a novel methodology for producing high performance air filter by combining melt blown technique with corona charging treatment. Changing the crystal structure of polypropylene by adding magnesium stearate can avoid charge escape and ensure the stability of filtration performances. Particularly, the influence of fiber diameter, pore size, porosity, and charge storage on the filtration performances of the filter are thoroughly investigated. The filtration performances of the materials, including the loading test performance are also studied. The melt blown materials formed by four layers presented a significant filtration efficiency of 97.96%, a low pressure drop of 84.28 Pa, and a high quality factor (QF) of 0.046 Pa^-1 for paraffin oil aerosol particles. Meanwhile, a robust filtration efficiency of 99.03%, a low pressure drop of 82.32 Pa, and an excellent QF of 0.056 Pa^-1 for NaCl aerosol particles could be easily achieved. The multi-layered melt blown filtration material developed here would be potentially applied in the field of protective masks.