High-Value-Added Application of Multi-Scale Nanofiber Membrane Derived from Recycled Waste Aramid Fibers for High-Temperature Resistance Filters

A considerable amount of aramid non-woven fabrics (i.e., leftover materials, defective goods, etc.) is produced during the processing of products, leading to waste of resources as well as environmental pollution. Herein, a new strategy was proposed to fabricated multi-scale poly(m-phenylene isophthalamide) nanofiber membranes (mPMIAs) based on high-value-added application of aramid non-woven fabrics for high-temperature resistance filters. First, ultrafine PMIA nanofibers with a diameter of 17.87±8 nm (uPMIAs) and conventional PMIA nanofibers with a diameter of 112±38 nm (cPMIAs) were produced using electrospinning, and mPMIAs with different ratios of cPMIAs to uPMIAs (4:0,3:1,2:2,1:3, and 0:4) were then fabricated by adjusting the number of spin units. The results show that when the ratio of cPMIAs to uPMIAs is 2:2 (mPMIAs (2:2)), the nanofiber membrane exhibits excellent mechanical properties (fracture strength of 61.778 MPa) and thermal stability (up to 340 °C). More importantly, the mPMIAs (2:2) maintained a filtration efficiency of 98.05% for PM0.3−10 at 300 °C. A particle vehicle exhaust filter was used to capture particles with a filtration efficiency that exceeded 97.51%. Hence, mPMIAs can potentially be utilized in high-temperature air filtration and industry filtration fields.