NOMEX^®Based Products

FAQ ON Nomex

What is Nomex^®?

It is a flame-resistant material invented by DuPont^™ in the 1960s. It began to be sold commercially in 1967.

Is Nomex^® a brand name?

Yes. Nomex^® is registered trademark owned by the American company DuPont^™, or DuPont™ de Nemours, for it’s meta-aramid material which it developed in the 1960s.

What are meta-aramid materials?

Aromatic polyamide is a type of synthetic fibre which is very strong and highly resistant to heat. Aramid is short for Aromatic polyamide.

Aramids itself are of two types – para and meta – which are differentiated by the way its linkages attach to the rings of carbon atoms. Nomex^® is a meta-aramid material.

Kevlar, another popular product from DuPont^™, is a para-aramid.

What is special about Nomex^®?

Nomex^® is highly flame-resistant which means it can be used in applications where there is exposure (or risk of exposure) to fire.

Whilst being a poor conductor of electricity, it has high dielectric strength and is therefore used as an electrical insulation material in a variety of applications.

What does Flame Resistant mean?

Flame Resistant materials are those which have an inherent ability to withstand a flame. To be specific, a flame-resistant material will catch fire if brought in direct contact with a flame, however, the fire will quickly extinguish when the flame is removed from the material. This is unlike other materials which when lit by a flame, will continue to be on fire even after the flame has been removed.

Further, unlike other materials, a flame-resistant material will not catch fire simply by being close to a flame or a high temperature heat source.

Why is Nomex^® flame resistant?

Nomex^® is woven with thick aramid fibers which are very poor conductors of heat. As a result, heat travels very slowly from one side of the material to the other.

Further, upon direct contact with a flame, the aramid fibres expand/swell, thus shutting out whatever little gaps there might have been through which heat could have passed.

What is the maximum temperature that Nomex^® can withstand?

Nomex^® can easily withstand temperatures up to 360°C (680°F). After this, the material will lose its strength, degrade quickly and eventually break.

Why is Nomex^® better than fire retardant materials?

Fire Retardant materials are simply coated with a special chemical that protects the material from fire. However, this coating can quickly wear off thus exposing the underlying material to the flame or heat source. On the other hand, Nomex^® does not use any coating. Instead, its fire-resistant capabilities are inherent as they are derived from its unique chemical structure.

Further, the chemicals used to make a material fire retardant, can be hazardous to human health over the long term, as compared to Nomex^® which is very safe for humans.

These characteristics makes Nomex^® a far more reliable and safer option as compared to fire retardant materials.

In which applications does the flame-resistant properties of Nomex^® help?

Nomex^® finds use anywhere and everywhere that humans can be exposed to fire. This includes firefighting, race car driving, mining, flying, etc. It is also used by astronauts and soldiers in the field of battle.

Besides specialist uses, Nomex^® is also used by the common person in day-to-day applications, for example, in oven gloves.

Is Nomex^® resistant to chemicals?

Nomex^® is remarkably resistant to acids and alkalis. It also remains unaltered by most solvents. Varnishes, adhesives, machine oils, etc., have little to no effect on it.

What is the effect of moisture on Nomex^®?

Moisture can cause havoc in electrical appliances, but not if Nomex^® is there! Nomex^® is highly resistant to moisture. To be precise, it can absorb a certain amount of moisture since it is hygroscopic in nature. However, that absorption of moisture does not meaningfully alter its dielectric, thermal, or mechanical properties.

Was there any single person behind the development of Nomex^®?

Wilfred Sweeny, a DuPont^™ scientist is generally considered to be the “inventor” of Nomex^®. It was his discoveries which eventually lead to the creation of Nomex^®.

Is Nomex^® water-proof?

Yes. Nomex^® is a tightly woven fabric that prevents water from passing through it.

Furthermore, because it is made from aramid fibers, which have hydrophobic properties, it does not react to water and, in fact, repels it. As a result, none of the qualities of Nomex^® are adversely affected by water.

What is the dielectric strength of Nomex^®?

Nomex^® has excellent dielectric strength. While different variants have different insulation levels, Nomex^® 410 paper, one of the popular Nomex^® products, offers a dielectric strength of approximately 900 V/mil (35 kV/mm).

What makes Nomex^® an excellent dielectric?

For electric current to pass through a material, it is critical for the material to have loosely bound or free electrons that can flow through it. Nomex^® does not possess these free electrons, thus enabling it to have very high dielectric strength.

Nomex^® is a registered trademark of DuPont^™