Structure and Properties of Dope-Dyed Poly(m-phenylene isophthalamide) Fibers By Wet Spinning

Abstract

Poly(m-phenylene isophthalamide) (PMIA) fiber was usually difficult to dye due to their rigid molecular structure and high crystallinity. In this study, the dope-dyed PMIA fibers with different amounts of pigment were prepared by wet spinning. The properties of the pigment were analyzed, including molecular structure, size distribution and dispersive properties. Measurements showed that the average diameter of pigment was no more than 100 nm, so pigments were easy to disperse in the fibers. The colour fastness of the coloured PMIA fibers was tested and their thermal properties and mechanical properties were also analyzed. The results of thermal gravity analysis (TGA) indicated that the coloured PMIA fibers maintained nice thermal performance. Compared to PMIA fibers, the coloured PMIA fibers became lighter after exposing to simulated sunlight for 50 h. The breaking tenacity of fibers exceeded 1.9 cN/dtex and the retentivity was above 85 % after being exposed to simulated sunlight for 50 h. The breaking tenacity of fibers exceeded 2.0 cN/dtex and the retentivity was above 80 % after being exposed to simulated sunlight for 50 h. These suggested the good mechanical performance of coloured PMIA fibers. This study successfully developed the dope-dyed PMIA fibers through wet spinning. The dyed performance of the coloured PMIA fibers was improved, while the thermal performance was also very nice. The mechanical properties of coloured fibers were similar to PMIA fibers.