Design and Synthesis of Flexible Meta-Aramid With Higher Dyeability

Meta-aramid (PMIA) is a high-performance polymer known for its exceptional properties, however, its molecular chain arrangement and strong hydrogen bonding contribute to its rigidity and brittleness. Additionally, the lack of reactive groups in its molecular structure severely affects the dyeing properties of PMIA, and restrains its applications in various fields. To address these issues, this study introduced 4,4′-thiodianiline (4,4′-TDA) into the main chain of PMIA molecules through copolymerization modification. This approach enhanced the relative molecular weight of the copolymers, resulting in co-PMIAs with improved flexibility. The synthesized copolymers demonstrated excellent mechanical properties and thermal stability, maintaining high strength while improving toughness. Furthermore, the incorporation of this thioether-containing monomer also enhanced the dyeing properties and flame retardancy of PMIA. The modification strategy employed in this research offers valuable insights into the structural modification of aromatic polyamides, and the synthesized novel copolymers show promising applications in the field of protective clothing.