Preparation of Ag@ZIF-8@PP Melt-Blown Nonwoven Fabrics: Air Filter Efficacy and Antibacterial Effect.

Serving as matrices, polypropylene (PP) melt-blown nonwoven fabrics with 4% electrostatic electret masterbatch were incorporated with a 6%, 10%, 14%, or 18% phosphorus-nitrogen flame retardant. The test results indicate that the incorporation of the 6% flame retardant prevented PP melt-blown nonwoven fabrics from generating a molten drop, which, in turn, hampers the secondary flame source while increasing the fiber diameter ratio. With a combination of 4% electrostatic electret masterbatch and the 6% flame retardant, PP melt-blown nonwoven fabrics were grafted with ZIF-8 and Ag@ZIF-8. The antibacterial effect of ZIF-8 and Ag@ZIF-8 was 40% and 85%, respectively. Moreover, four reinforcing measures were used to provide Ag@ZIF-8 PP melt-blown nonwoven fabrics with synergistic effects, involving lamination, electrostatic electret, and Ag@ZIF-8 grafting, as well as a larger diameter because of the addition of phosphorus-nitrogen flame retardants. As specified in the GB2626-2019 and JIS T8151-2018 respiratory resistance test standards, with a constant 60 Pa, Ag@ZIF-8 PP melt-blown nonwoven membranes were tested for a filter effect against PM 0.3. When the number of lamination layers was five, the filter effect was 88 ± 2.2%, and the respiratory resistance was 51 ± 3.6 Pa.