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 +/- 0.49Pa, and a satisfied quality factor of 0.03898 +/- 0.0001Pa-1 for sodium chloride particles with an aerodynamic diameter of 0.26m at the airflow rate of 85Lmin-1. More importantly, the resultant filter exhibited a large dust holding capacity of 23.5 +/- 0.41gm-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. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47827.