Preparation, Air Filtration Performance of a Fluorinated Polyimide/Polyacrylonitrile Nanofibrous Membrane by Electrospinning

This paper reports the successful fabrication of a new nanofibrous membrane, F-PI/PAN, through electrospinning of polyacrylonitrile (PAN) and fluorinated polyimide (F-PI). The nanofibrous membrane exhibits comprehensive properties for high-temperature filtration and robust PM2.5 (particulate matter with an aerodynamic equivalent diameter of 2.5 microns or less) removal. The introduction of F enhances the hydrophobicity of the PI. The relationship between the hydrophobic performance and the filtration performance of particles is investigated. The chemical group of the composite membrane was demonstrated using FITR, while the surface morphology was investigated using field emission scanning electron microscopy. The TGA results indicated good thermal stability at 300 °C. Various ratios of F-PI membranes were prepared to characterize the change in properties, with the optimal mass ratio of F-PI being 20 wt%. As the proportion of F-PI increases, its mechanical and filtration efficiency properties and hydrophobicity become stronger. The contact angle reaches its maximum of 128 ± 5.2° when PAN:F-PI = 6:4. Meanwhile, when PAN:F-PI = 8:2, the filtration efficiency reaches 99.4 ± 0.3%, and the elongation at break can reach 76%. The fracture strength can also reach 7.1 MPa, 1.63 times that of the pure PAN membrane.