aramid

Aramid is a family of synthetic polymers known for high strength and heat resistance. The term aramid stands for aromatic polyamide, referring to polyamide chains that include aromatic rings in the backbone. The two principal classes are para-aramid and meta-aramid, differing in the linkage pattern of the aromatic rings. Para-aramids, such as Kevlar and Twaron, offer very high tensile strength and stiffness, excellent abrasion resistance, and outstanding dimensional stability. Meta-aramids, such as Nomex, tend to show greater thermal stability and resistance to high-temperature deformation, but lower strength and stiffness compared with para-aramids.

They are produced by condensation polymerization of aromatic diamines with diacid chlorides to form polyaramid chains, which are dissolved and spun into fibers using wet or dry spinning methods; drawing aligns the molecules to increase strength.

Properties include high strength-to-weight ratio, high modulus, resistance to many chemicals, and a high decomposition temperature; they do not melt under heat, instead they char and decompose. However, they can be attacked by strong oxidizers and concentrated acids; exposure to ultraviolet light without stabilization can gradually degrade some formulations.

Applications across protective equipment (ballistic vests, helmets, cut-resistant gloves), high-performance composites for aerospace, automotive, wind energy; reinforcement for tires and hoses; protective clothing.

History: Developed in the 1960s–70s by DuPont and other companies; aramid means aromatic polyamide; widely used in modern industry.