Enhanced Air Filtration Performances by Coating Aramid Nanofibres on a Melt-blown Nonwoven

Nanofibre membranes with small diameter and large specific surface area are widely used in filtration fields due to their small pore size and high porosity. To date, aramid nanofibres (ANFs) have received extensive research interests because of their high stiffness and excellent temperature resistance. However, the preparation of ANFs usually takes a long period, which greatly hampers the practical application of these fibres. Herein, we report the preparation of ANFs by a modified deprotonation method under elevated temperature. Owning to the increase of temperature, the preparation cycle of ANFs was shortened in 8 hours. The resulting ANFs dispersion was further coated on a polypropylene melt-blown nonwoven to form a composite nonwoven filter. With the submicron porous structure, the filtration efficiency, pressure drop and quality factor of the filter were 95.61%, 38.22 Pa and 0.082 Pa-1, respectively. Compared to pristine nonwoven, the filtration, mechanical, and heat insulation properties of the composite filter were also significantly improved. This work may offer a simple and efficient way for enhancing the air filtration performances of current filters.