Aerosol filtration performance of electrospun membranes comprising polyacrylonitrile and cellulose nanocrystals

Composite electrospun membranes of polyacrylonitrile (PAN) with contents of cellulose nanocrystals (CNCs) of 5-20 wt% were prepared. The increase in cellulose content improved the mechanical properties of the materials up to approximately 2-fold in the tensile strength and 6-fold in elastic modulus compared to the PAN membrane. Filtration performance of the composite membranes against aerosolized salt nanoparticles was evaluated under conditions relevant to their use as active layers in Filtering Facepiece Respirators (FFR), such as N95s. In general, all composite membranes presented values of filtration efficiency (FE) superior to 90%. Pressure drop (Delta p) values of the materials, in general, decreased with increasing content of CNCs. In general, an increase of the quality factor (QF) was observed with increasing content of CNCs in the membrane compositions, possibly due to a trend for the porosity of the composite materials to increase. The membrane containing 20 wt% of CNCs presented the highest QF (0.034 +/- 0.002 Pa-1), one of the highest FE of 95.97 +/- 0.62%, particle penetration (P) of 4.03 +/- 0.62%, and the lowest Delta p of 9.60 +/- 1.04 mmH2O. Thus, it is possible to prepare composite membranes of PAN reinforced with high content of natural, biodegradable, and abundant CNCs, and to evaluate comprehensively their potential to be used in air filtration applications such as respirators and cleanroom filters.

Automated summary

Composite electrospun membranes of PAN with cellulose nanocrystals (CNCs) content of 5-20 wt% were prepared. The mechanical properties improved with increasing cellulose content, and all membranes showed filtration efficiency above 90%.