Aromatic polyamides or aramids are materials with exceptional thermal and mechanical properties. For this reason, they are considered high-performance materials with a multitude of applications in fields such as civil security (bullet-proof body armour or fire, chemical and saw protection suits), transport (automotive and aerospace) and civil engineering, among many others. The remarkable properties arise from the high cohesive energy as a consequence of their chemical structure, including the rigidity of the main chain due to the wholly aromatic structure conjugated with the amide groups, the high average bond energy and a strong and highly directional interchain hydrogen bonds between the amide moieties. Although in some industrial applications the natural yellowish colour of the fibres is used, generally most of the applications require coloured fibres. However, aramid fibres have poor dyeing properties, for the same reasons that make them thermally and mechanically resistant, and traditional dyeing methods such as dope dying, are inefficient and aggressive, which impairs fibres properties.

Ideal colour fastness of fibres is achieved by intrinsically, inherently or self-coloured polymers, by introducing a dye motif or chromophore monomer in the chemical structure of the polymer. In addition, the colour hue can be controlled by means of tuning the chromophore monomer molar content in the final composition. In a previous research, we successfully obtained inherently blue coloured aramids, with blue chromophore motifs unable to migrate and evenly distribute along the polymer chain and maintaining their high performance properties, and our aim now is to obtain red coloured aramids prepared in the same fashion.