Design of three‐dimensional gradient nonwoven composites with robust dust holding capacity for air filtration

Air pollution has seriously threatened public health in developing countries. However, it is still a big challenge for fabricating a filter with high filtration efficiency, low air resistance, and long service life. Herein, we report a facile strategy to fabricate a multilayered nonwoven composite with a functionally gradient structure for air filtration by a combined method of needle‐punch, melt blown, and corona charging techniques. Our integrated multilayer needle‐punched/melt blown composite filter could achieve a high filtration efficiency up to 99.52 ± 0.01%, a low pressure drop of 136.87 ± 0.49 Pa, and a satisfied quality factor of 0.03898 ± 0.0001 Pa −1 for sodium chloride particles with an aerodynamic diameter of 0.26 μm at the airflow rate of 85 L min −1 . More importantly, the resultant filter exhibited a large dust holding capacity of 23.5 ± 0.41 g m −2 , which indicates a long service life. It is expected that our multilayer needle‐punched/melt blown composite fabric may not only serve as a good candidate for air filtration, but also provide a new sight for designing the air filtration materials. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47827.