Aramidu

Aramidu, or aramid in English, is a class of high‑performance polymers composed of aromatic rings linked by amide bonds. The rigid, conjugated structure imparted by the aromatic rings gives aramids high strength and stiffness, along with excellent heat resistance and flame retardance. They are commonly described as para-aramids and meta-aramids, depending on the position of the amide linkages relative to the phenyl rings.

Para-aramids include poly-paraphenylene terephthalamide (PPTA), produced for use in high-strength fibers such as Kevlar and Twaron. Meta-aramids include poly-m-phenylene isophthalamide (PMIA), used in flame‑resistant fabrics such as Nomex. The two groups exhibit complementary properties: para-aramids offer very high tensile strength and modulus, while meta-aramids provide excellent heat resistance and dimensional stability at elevated temperatures. Aramids are often used in blends and composites to tailor performance.

Synthesis and processing of aramids typically involve condensation reactions between aromatic diacid chlorides and diamines, forming long chains with amide linkages. They are not melt-processable in the same way as many other polymers because of strong interchain interactions and high crystallinity. Most PPTA and PMIA grades are processed from concentrated sulfuric acid or other solvents into fibers by wet-spinning or gel-spinning, followed by drawing to increase chain orientation. Some forms are manufactured as nonwoven fabrics or reinforced composites.

Applications include ballistic protective armor, protective clothing and helmet linings, reinforcing fibers for tires and aerospace/automotive composites, electrical insulation, and filtration membranes. Aramids offer a combination of high strength, low weight, abrasion resistance, and flame retardance, contributing to their use in safety-critical and engineering applications.