Super fine para-aramid nanofiber and membrane fabricated by airflow-assisted coaxial spinning

Abstract

Para-aramid nanofiber membranes (ANFMs) have gained significant attention owing to their excellent properties. However, the preparation of ANFM remains a challenge. The amount of entanglement in the ANF dispersion is insufficient, which is why the ANFM cannot be prepared directly through conventional spinning methods. Therefore, we proposed an airflow-assisted coaxial spinning (AFAS) method. A flexible polymer (polyethylene oxide (PEO)), was employed as the outer spinning solution for improving the spinnability of the precursor solution, thus facilitating the efficient preparation of a well-shaped ANFM. The AFAS method reported herein is effective for preparing para-aramid nanofibers and ANFMs. ANFM was successfully fabricated by AFAS, consisting of nanoscale superfine ANFs ranging from 20 to 25 nm, a small average pore size of 0.2 μm, and high porosity (exceeding 80 %). Additionally, the ANFM exhibits prominent mechanical properties (tensile strength = 88.3 MPa; Young's modulus: E = 1.5 GPa), good flexibility, an excellent flame retardancy and thermal stability (300 °C) and flame retardancy.