Intrinsically magenta-colored aramids with enhanced mechanical performance

Poly(p-phenylene terephthalamide) (PPTA) and poly(m-phenylene isophthalamide) (MPIA) are highly valued polymers widely used as fibers and textiles, owing to their exceptional mechanical and thermal properties. However, their high crystallinity and dense molecular packing hinder dyeing, limiting their use in applications that require specific coloration. This work presents the design and characterization of intrinsically colored aramids, in which a magenta dye is covalently bonded as a lateral chain to the main backbone of the parent polymers. The resulting materials incorporated 1, 10, 25, and 100 mol% of the structural units containing the dye, and the color hue was proportional to the dye content.

The results revealed that the introduction of the dye led to a 94 % increase in the Young's modulus, a 35 % increase in the tensile strength, and a 12 % increase in the elongation at break for Ar-25 compared to MPIA. X-ray diffraction analysis revealed the presence of crystalline domains in the synthesized polymers, which would explain the increased mechanical performance of the materials compared to laboratory-synthesized MPIA.

By incorporating color directly into the polymer backbone, this approach eliminates the need for conventional dyeing of fibers, reducing the environmental impact, while ensuring long-term color stability. Additionally, the magenta color, which is a primary hue, enables the formulation of a broad spectrum of shades. These findings pave the way for advanced aramid-based materials for fiber-related applications, with enhanced mechanical properties and customizable coloration, expanding their potential in textiles, protective gears, and high-performance structural applications.