Nomex is produced by condensation reaction from the monomers m-phenylenediamine and isophthaloyl chloride. Like Kevlar, it is an aramid polymer related to nylon but with an aromatic backbone that makes it more rigid and more durable. Nomex is a meta variant of the aramids; unlike the para-aramid Kevlar, Nomex strands cannot align during filament polymerization and have lower tensile strength at 340 MPa (49,000 psi). In exchange, it offers excellent thermal, chemical, and radiation resistance. Kevlar is frequently added to Nomex to increase its resistance to tearing.
Wilfred Sweeny (1926–2011), the DuPont scientist primarily responsible for the discoveries leading to Nomex, received a DuPont Lavoisier Medal in 2002 partly for that work.
The deaths in fiery crashes of racing drivers Fireball Roberts at Charlotte, and Eddie Sachs and Dave MacDonald at Indianapolis in 1964, were pivotal in driving the adoption of flame-resistant fabrics in motorsport. In early 1966, Competition Press and Autoweek reported that experimental Nomex driving suits had been worn by Walt Hansgen, Masten Gregory, Marvin Panch, and Bob Tullius during the previous season. The goal at that stage was to gather use-test information on the comfort and laundering characteristics of the material before wider adoption.
It is sold in both fibre and sheet forms. The hood — a Nomex balaclava placed on the head — is a common piece of racing equipment that protects portions of the head not covered by the helmet. Driving suits are typically multi-layer constructions: the outer shell is Nomex, while inner layers often incorporate additional fire-resistant materials. Gloves, socks, and undergarments made from Nomex complete the ensemble, with each element contributing to the total protection time in the event of an on-car fire.
Military pilots and aircrew wear flight suits made of over 92 percent Nomex to protect them from cockpit fires, a parallel application that shares the same underlying material science as the racing suit.
Nomex has numerous applications outside motorsport. Nomex paper is used in electrical laminates such as circuit boards and transformer cores, and as fireproof honeycomb structures — often saturated with phenolic resin — in aircraft construction. Wildland firefighters wear Nomex shirts and trousers as part of their personal protective equipment during wildfire suppression. Military tank crews and naval anti-flash personnel also use Nomex for fire protection.
In industrial settings, Nomex serves as a filter material in exhaust filtration systems (baghouses) dealing with hot gas emissions at asphalt plants, cement plants, steel smelting facilities, and non-ferrous metal production facilities. It has even been used as an acoustic material: the Experimental Media and Performing Arts Center (EMPAC) concert hall at Rensselaer Polytechnic Institute in Troy, New York, uses a Nomex canopy to reflect high- and mid-frequency sound while allowing lower frequencies to pass through.
The transition from cotton to Nomex driving suits in the 1960s represents one of the most consequential safety advances in motorsport history. Where early racing drivers wore little more than ordinary clothing, the systematic adoption of certified multi-layer Nomex suits — eventually formalized by the FIA into specific homologation standards — transformed the survival odds of cockpit fires. The same base material and manufacturing logic that proved itself on American oval tracks in the mid-1960s underpins the fire suits worn at the Formula One level today.