Study on the Performance Characterization and Yarn Mechanical Properties of Poly-M-phenylene Isophthalamide Nanofiber

In this paper, poly- m-phenylene isophthalamide (PMIA) staple fibers were dissolved in a LiCl/ N, N-dimethylacetamide solvent system in order to prepare PMIA nanofibers via the electrospinning method. The mean diameter of the nanofiber was between 72 and 247 nm and gradually increased with increasing LiCl concentration. PMIA nanofibers were characterized by scanning electron microscopy, Fourier transform infrared spectrometry, a thermogravimetric analyzer and Brunauer–Emmett–Teller analysis. Besides, the tensile strength of PMIA nanofiber yarns was tested and analyzed, combining the orthogonal array method. The results showed that the diameter and uniformity of nanofibers decreased gradually with increasing PMIA and LiCl solution concentration. The thermal properties, the specific surface area and chemical structures of PMIA nanofibers were improved comparing with PMIA stable fiber. It was found out that the LiCl concentration could influence the interactions among polymer molecules and caused the fibrils to wrap around each other, forming fiber clusters. The LiCl concentration was the most important factor affecting the tensile strength of PMIA nanofiber yarn.