Nomex is a flame-resistant and heat-resistant synthetic aromatic polyamide developed by DuPont. It is used in protective clothing for race car drivers, firefighters, soldiers and astronauts. Nomex fibers are woven into a tough material that is inherently flame resistant and a poor conductor of heat, protecting the wearer from burns. It has numerous applications including protective clothing, electrical insulation, and structural reinforcement in aircraft and vehicles due its strength, heat resistance and flame retardant properties. Nomex was invented in 1967 by Dr. Wilfred Sweeny and has saved many lives since.

1. Nomex®
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by Chris Woodford. Last updated: September 22, 2014.
It's a racing driver's worst nightmare. You come down the straight at over 200mph (300 kph),
a tire blows out, and you skid off into the crash barrier. You survive the crash but the energy
of the impact generates enough heat to make your fuel tank explode. Suddenly, the car that
could have carried you to victory has turned into a fireball. You manage to escape, but now
there's another terrifying threat: your overalls catch fire! Fortunately, you're wearing an inner
body-suit made of an amazing flame-resistant material called Nomex®. So, as you pelt from
the car, the fire goes out all by itself. Shaken but unharmed, you owe your life to an piece of
amazing chemical technology. Let's take a closer look at how Nomex works and some of the
other things it can be used for!
Photo: A soldier puts on a Nomex® hood and a flameproof suit. Photo by Ryan C. Matson
courtesy of US Army.
What is Nomex?
Photo: A pair of Nomex® gloves like these could make nasty oven burns a thing of the past.
Nomex® is the brand name for a heat- and flame-resistant textile made by the DuPont™
chemical company. Technically, it's called a synthetic aromatic polyamide polymer—which
sounds complex but starts to make more sense if you consider it one word at a time:
 Synthetic textiles are made in a chemical laboratory (unlike natural textiles such as
cotton, which grows on plants, and wool, which comes from animals).
 Aromatic means its molecules have a strong, ring-like structure not unlike that of
benzene.

2.  Polyamide means the ring-like aromatic molecules connect together to form long
chains. These run inside (and parallel to) the fibers of Nomex a bit like the steel bars
in reinforced concrete.
 Polymer means that Nomex is made from many identical molecules bonded together
(each one of which is called a monomer). Plastics are the most familiar polymers in
our world. As we've seen, the monomers in Nomex are based on a modified, benzene-like
ring structure.
In short, what we have in Nomex is a man-made textile whose ring-like monomers are
bonded together into tough, long chains to make immensely strong fibers. Break Nomex up
and sort it into its atoms and you'd have four neat piles of carbon hydrogen, oxygen, and
nitrogen.
Photo: Left: Turn Nomex gloves inside out and you can see how very thickly woven they are.
Although they look much like ordinary woollen gloves, wool alone could never give such
amazing heat protection. Right: Inspect the label carefully and you'll see this is actually
Nomex III, which is roughly 95 percent Nomex, 5 percent Kevlar, and a little carbon fiber to
reduce static.
Aromatic polyamides such as Nomex are often called aramids for short. Kevlar® (another
DuPont textile) is also an aramid, but with a slightly different chemical structure. If you're
interested, the full chemical name of Nomex is poly (m-phenylenediamine isophthalamide),
while Kevlar is poly (p-phenylenediamine terephthalamide); Nomex is a meta-aramid
polymer while Kevlar is a para-aramid polymer.
Aramids are made in a two-stage process. First, the basic polymer is made by reacting
together organic (carbon-based) substances to form a liquid. In the second stage, the liquid is
spun out to make solid fibers, which can then be woven into textiles or converted into sheet
form.
Nomex generally comes in three kinds. It's either used by itself (as 100 percent Nomex),
blended with up to 60 percent Kevlar, or blended with Kevlar and some anti-static fibers. In
this last form, it's known as Nomex III.
What makes Nomex fireproof?
Two superb properties of Nomex make it a perfect protective material for race-car drivers.
Although Nomex burns when you hold a flame up to it, it stops burning as soon as the heat
source is removed. In other words, it is inherently flame resistant. Just as important, the thick

3. woven structure of synthetic fibers is a very poor conductor of heat. It takes time for heat to
travel through Nomex; hopefully by that time, you're away from the flames and out of
danger.
The tough, woven structure of Nomex is extremely strong, has high heat resistance, is flame
retardant (it doesn't melt or drip) and doesn't react with water.
What is Nomex used for?
Photo: Ready for battle: soldiers put on body armor made from Kevlar and Nomex and used
by explosives experts. Photo by courtesy of US Army and Defense Visual Information
Center.
Nomex is best known as a barrier to fire and heat. Apart from race-car drivers, it's worn by
astronauts, fire-fighters, and military personnel. It's also widely used in more mundane ways,
such as in my household oven gloves. In sheet form, heatproof Nomex finds many uses in
automobiles, including high-temperature hoses and insulation for spark plugs.
But Nomex isn't just useful for protective clothing. The molecular structure that stops heat
passing through stops electricity flowing through it as well. That means Nomex is an
extremely poor conductor—almost a perfect insulator, in fact. Nomex, made into the form of
a paper sheet or board, is a superb insulating material for all kinds of electrical equipment,
from motors and generators to transformers and other electrical equipment. For these
applications, Nomex is often laminated with Mylar® (polyester film) to make a stronger,
tougher insulating material that works at high temperatures without the individual layers
coming apart. Two-ply Nomex-Mylar laminate is called NM; three-ply is known as NMN
(where the Nomex goes either side of the Mylar); and four ply is NMNM.
Like Kevlar, Nomex is both very strong and very light, so it's often used in aerospace
applications. Nomex sheet is widely used to make the honeycomb reinforcement inside
helicopter blades and airplane tail fins.

4. Photo: Nomex isn't the only fire-retardant fabric. Textiles used to cover chairs are often made
from fire-resistant polyesters and other materials. This simple demonstration in Think Tank
(the science museum in Birmingham, England) shows very clearly how fabrics like these can
save lives. On the left, we have a chair made from ordinary fabric. A cigarette or match burn
sets the fabric alight very quickly and gives off toxic fumes. Had this fire been left to burn,
the whole chair (and the rest of the room) would have been completely destroyed. On the
right, a chair made from fire-retardant fabric burns much slower. Often the fire goes out
before too much damage is done.
Who invented Nomex?
The credit for this excellent invention goes to Dr Wilfred Sweeny, a Scottish-born scientist
working at the world-famous DuPont laboratory in Wilmington, Delaware that also spawned
nylon and Kevlar. While researching polymers, he developed one with with particularly good
thermal properties that could be woven into a very tough fiber. Since Nomex was introduced
in 1967, it has saved the lives of countless firefighters, pilots, soldiers, industrial workers—
and, of course, racing drivers!
Velocidade, curvas perigosas e muita adrenalina. Para arriscar a vida a mais de 300 km/h os
pilotos precisam ter certeza de que estão bem protegidos. Para ter confiança e ousar em
ultrapassagens que os motoristas comuns nem podem imaginar, os pilotos precisam, entre as
muitas coisas que essa atividade exige, de uma roupa especial. Por isso, ao longo dos anos, os
macacões para pilotos de corrida evoluíram muito e se transformaram em itens
tecnologicamente sofisticados, que combinam máxima proteção com um impecável conforto.
O macacão é produzido com um tecido importado à base de aramida e é resistente ao fogo.
Todo material é produzido para não pegar fogo: o forro, o zíper, a malha e até a linha de costura.
Mas como você está acostumado, os macacões são também os responsáveis por marcar o estilo
de cada piloto e sua equipe, além de ser uma grande vitrine para os patrocinadores.
Por isso, a produção final do macacão acontece quando o cliente leva o seu logotipo e escolhe

5. as cores que serão predominantes na peça. Em seguida é feito o molde e por ultimo é colocado
o forro. Somente após sua confecção completa é que são bordados os patrocínios e o macacão
finalmente fica pronto para encarar as pistas. E isso tudo leva em aproximadamente quinze
dias, além de garantir muito estilo, esses macacões são parte muito importante para que os
pilotos profissionais corram total tranquilidade e segurança
Aramids are a family of nylons, including Nomex® and Kevlar®. Kevlar® is used to
make things like bullet proof vests and puncture resistant bicycle tires. I suppose one
could even make bullet proof bicycle tires from Kevlar® if one felt the need.
Blends of Nomex® and Kevlar® are used to make fireproof clothing. Nomex® is what
keeps the monster truck and tractor drivers from burning to death should their fire -
breathing rigs breathe a little too much fire. Thanks to Nomex®, an important part of
American culture can be practiced safely. (Polymers play another part in the monster
truck show in the form of elastomers from which those giant tires are made.) Nomex®-
Kevlar® blends also protect fire fighters.
Kevlar® is a polyamide, in which all the amide groups are separated by para-phenylene
groups, that is, the amide groups attach to the phenyl rings opposite to each other, at
carbons 1 and 4. Kevlar is shown in the big picture at the top of the page.
Nomex®, on the other hand, has meta-phenylene groups, that is, the amide groups are
attached to the phenyl ring at the 1 and 3 positions.

6. Kevlar® is a very crystalline polymer. It took a long time to figure out how to make
anything useful out of Kevlar® because it wouldn't dissolve in anything. So processing it
as a solution was out. It wouldn't melt below a right toasty 500 oC, so melting it down
was out, too. Then a scientist named Stephanie Kwolek came up with a brilliant plan.
Click here to find out what it was.
Aramids are used in the form of fibers. They form into even better fibers than non-aromatic
polyamides, like nylon 6,6.
Why? Why?
Ok, since it seems everyone just has to know, I'll tell you. It has to do with a little quirky
thing that amides do. They have the ability to adopt two different shapes, or
conformations. You can see this in the picture of a low molecular weight amide. The two
pictures are the same compound, in two different conformations. The one on the left is
called the trans conformation, and the one on the right is the cis- conformation.
In Latin, trans means "on the other side". So when the hydrocarbon groups of the
amide are on opposite sides of the amide bond, the bond between the carbonyl oxygen
and the amide nitrogen, it's called a trans-amide. Likewise, cis in Latin means "on the
same side", and when both hydrocarbon groups are on the same side of the amide bond,
we call it a cis-amide.

7. The same amide molecule can twist back and forth between the cis- and trans-conformations,
given a little bit of energy.
The same cis- and trans-conformations exist in polyamides, too. When all the amide
groups in a polyamide, like nylon 6,6 for example, are in the trans conformation, the
polymer is fully stretched out in a straight line. This is exactly what we want for fibers,
because long, straight, fully extended chains pack more perfectly into the crystalline
form that makes up the fiber. But sadly, there's always at least some amide linkages in
the cis-conformation. So nylon 6,6 chains never become fully extended.

8. But Kevlar® is different. When it tries to twist into the cis-conformation, the hydrogens
on the big aromatic groups get in the way! The cis conformation puts the hydrogens just
a little closer to each other than they want to be. So Kevlar® stays nearly fully in the
trans- conformation. So Kevlar® can fully extend to form beautiful fibers.
Now it may help to look at a close-up picture of this. Look at the picture below and you
can see that when Kevlar® tries to form the cis-conformation, there's not enough room
for the phenyl hydrogens. So only the trans-conformation is usually found.

9. But there's another polymer that stretches out even better called ultra-high molecular
weight polyethylene. It even replaced Kevlar® for making bullet-proof vests!
But back to Kevlar®...
Also the phenyl rings of adjacent chains stack on top of each other very easily and
neatly, which makes the polymer even more crystalline, and the fibers even stronger.
Nomex
From Wikipedia, the free encyclopedia

10. A Canadian firefighter in Toronto affixes a Nomex hood in 2007.
Nomex is a registered trademark for flame-resistant meta-aramid material developed in the
early 1960s by DuPont and first marketed in 1967.[1]
Contents
 1 Properties
 2 Production
 3 Applications
 4 History
 5 See also
 6 References
 7 External links
Properties
Nomex and related aramid polymers are related to nylon, but have aromatic backbones, and
hence are more rigid and more durable. Nomex is the premier example of a meta variant of
the aramids (Kevlar is a para aramid). Unlike Kevlar, Nomex cannot align during filament
formation and has poorer strength. However, it has excellent thermal, chemical, and radiation
resistance for a polymer material.
Production
The polymer is produced by condensation reaction from the monomers m-phenylenediamine
and isophthaloyl chloride.[1]
It is sold in both fiber and sheet forms and is used as a fabric wherever resistance from heat
and flame is required. Nomex sheet is actually a calendered paper and made in a similar
fashion. Nomex Type 410 paper is the original and one of the larger grade types made,
mostly for electrical insulation purposes. Nomex fiber is made in the USA and in Spain
(Asturias).
Wilfred Sweeny (1926–2011), the DuPont scientist responsible for discoveries leading to
Nomex, earned a DuPont Lavoisier Medal[2] partly for this work in 2002.
Applications

11. The paper is used in electrical laminates such as circuit boards and transformer cores as well
as fireproof honeycomb structures where it is saturated with a phenolic resin. Honeycomb
structures such as these, as well as mylar-Nomex laminates are used extensively in aircraft
construction. Both the firefighting and vehicle racing industries use Nomex to create clothing
and equipment that can withstand intense heat.
A Nomex hood is a common piece of racing and firefighting equipment. It is placed on the
head on top of a firefighter's face mask. The hood protects the portions of the head not
covered by the helmet and face mask from the intense heat of the fire.
Wildland firefighters wear Nomex shirts and trousers as part of their personal protective
equipment during wildfire suppression activities.
Race car drivers wear driving suits constructed of Nomex and or other fire retardant
materials, along with Nomex gloves, long underwear, balaclavas, socks, helmet lining and
shoes to protect them in the event of a fire. The FIA and the SFI Foundation provide
specifications for flame-resistant drivers clothing to be used in racing. The standards range
from single layer suits that provide some protection against flash fires to much thicker
multilayer SFI-15 suits required by the National Hot Rod Association that can protect a driver
for up to 30 seconds against the intense heat and almost invisible flames generated by the
nitromethane, ethanol and methanol fuels that are used in championship drag racing.
Military pilots and aircrew wear flight suits made of over 92 percent Nomex to protect them
from the possibility of cockpit fires and other mishaps. Recently, troops riding in ground
vehicles have also begun wearing Nomex. The remaining material is typically Kevlar thread
used to hold the fabric together at the seams.
Military tank drivers also typically use Nomex hoods as protection against fire and extreme
cold. [3]
In the U.S. space program, Nomex has been used for the Thermal Micrometeoroid Garment
on the Extravehicular Mobility Unit (in conjunction with Kevlar and Gore-Tex) and ACES
pressure suit, both for fire and extreme environment (water immersion to near vacuum)
protection, and as thermal blankets on the payload bay doors, fuselage, and upper wing
surfaces of the Space Shuttle Orbiter. It has also been used for the airbags for the Mars
Pathfinder and Mars Exploration Rover missions, the Galileo atmospheric probe, the Cassini-
Huygens Titan probe, as an external covering on the AERCam Sprint, and is planned to be
incorporated into NASA's upcoming Crew Exploration Vehicle.
Nomex has also been used for its acoustic qualities, the first time being used in Troy, NY, at
Rensselaer Polytechnic Institute's Experimental Media and Performing Arts Center
(EMPAC's) main concert hall. A ceiling canopy of Nomex reflects high and mid frequency
sound, providing reverberation, while letting lower frequency sound partially pass through
the canopy.[4] According to RPI President Shirley Ann Jackson, EMPAC is the first venue in
the world to use Nomex for acoustic reasons.
Nomex (like Kevlar) is also used in the production of loudspeaker drivers.
Honeycomb-structured Nomex paper is also used as a spacer between layers of lead in the
ATLAS Liquid Argon Calorimeter.[5]

12. History
The death of race car drivers in fiery crashes, notably those of Fireball Roberts at Charlotte,
and Eddie Sachs and Dave MacDonald at Indianapolis, all in 1964, meant something had to
be done.[6] In early 1966 Competition Press and Autoweek reported: "During the past season,
experimental driving suits were worn by Walt Hansgen, Masten Gregory, Marvin Panch and
Group 44's Bob Tullius; these four representing a fairly good cross section in the sport. The
goal was to get use-test information on the comfort and laundering characteristics of Nomex.
The Chrysler-Plymouth team at the recent Motor Trend 500 at Riverside also wore these
suits."[7]
Propiedades del Kevlar y
del Nomex
Las propiedades de estos dos materiales van ligadas intrínsecamente a las
aplicaciones que podemos encontrar tanto en la industria como en la vida
cotidiana, las cuales se ven en el siguiente punto.
No derriten ni se contraen en llama, y carbonizan
solamente a temperaturas muy altas. Ofrecen una
resistencia excelente al agua y al petróleo, incluyendo
el aceite de motores y lubricantes, además tienen una
buena resistencia química y son químicamente estables
bajo una gran variedad de condiciones de exposición.
Son ambos extremadamente resistentes y con alta
resistencia a la abrasión, además se cortan y se rasgan.
NOMEX® es un polímero aromático sintético de poliamida que proporciona altos
niveles de la integridad eléctrica, química y mecánica.
Esto es lo que hace que NOMEX® no se contraiga, ni dilate, ni se ablande ni
derrita durante la exposición a corto plazo a temperaturas tan altas como

13. 300°C. A largo plazo puede estar trabajando como aislante tanto térmico como
eléctrico o químico soportando continuamente temperaturas de hasta 220°C
durante más de 10 años.
La fuerza y la resistencia de los papeles y de los cartones prensados de
NOMEX® ayudan a ampliar vida del equipo que rota en condiciones de
funcionamiento severas. Estas condiciones incluyen choque severo y
vibraciones excesivas propiciadas por desequilibrios rotantes, como por
ejemplo las que pueden aparecer en molinos de acero, motores para tracción
ferroviaria, o turbinas de gas. En todos ellos además tenemos grandes
temperaturas de funcionamiento.
Fuerza dieléctrica inherente
En tensiones eléctricas muy elevadas, como
cortocircuitos, a corto plazo los productos de
NOMEX® de 18 a 40 V/mil de kV/mm (457 a 1015),
dependiendo de tipo de producto y grueso,
proporcionan la protección necesaria y adecuada.
Dureza mecánica
Los productos de alta densidad de NOMEX® son
fuertes, resistentes y (en los grados más finos)
flexibles, con buena resistencia al rasgado y a la
abrasión.
Estabilidad termal
Las temperaturas hasta 200°C tienen poco o nada de efecto en las
características eléctricas y mecánicas de los productos de NOMEX®, y los
valores útiles se conservan en temperaturas considerablemente más altas.
Además, estas características útiles se mantienen por por lo menos 10 años de
exposición continua a 220°C de temperatura.
Compatibilidad química

14. NOMEX® es esencialmente inerte a la mayoría de
los disolventes, y es totalmente resistente a los
ataques de ácidos y álcalis. Es compatible con
todas las clases de barnices y de pegamentos, de
líquidos de transformadores, de aceites
lubricantes, y de refrigerantes. Puesto que los
productos de NOMEX® no son digestibles, no son
atacados por insectos, hongos, etc.
Capacidades criogénicas
NOMEX® ha encontrado una gran aceptación en una variedad de usos
criogénicos debido a su estructura polimérica única. En el punto que hierve el
nitrógeno (77°K), los cartones prensados de papel de NOMEX® resisten
plenamete las fuerzas de contracción/dilatación que aparecen.
Insensibilidad a la humedad
En equilibrio con un 95 por ciento de humedad relativa, los papeles de NOMEX®
y los cartones prensados mantienen un 90 por ciento de su fuerza dieléctrica,
mientras que muchas características mecánicas además mejoran.
Resistencia de la radiación
NOMEX® es esencialmente inafectado por 800 megarads (8Mgy) de radiación de
ionización y todavía conserva características mecánicas y eléctricas útiles
después de ocho veces esta exposición.
No toxicidad
Los productos de NOMEX® no producen ninguna
reacción tóxica conocida en seres humanos o
animales. Los productos de NOMEX® no se derriten
y, con un índice limitador del oxígeno (LOI) en 220°C
sobre 20,8 (el valor crítico para la combustión en
aire normal), no favorecen la combustión.

15. Estructura química del
Kevlar y del Nomex:
El Kevlar y el Nomex pertenecen a la familia de las aramidas, las cuales , a su
vez, pertenecen a una familia de nylons. Todos ellos son polímeros. Algunos otros
polímeros sintéticos comunesson el Teflon, la Lycra, y el poliéster. Un polímero es una
cadena hecha de muchos grupos moleculares similares, conocido como monómeros, que
se enlazan juntos. Para conseguir entender mejor todo esto, imagínese que está mirando
un tren de mercancías muy largo. Cada vagón idéntico podría representar un
monómero y el tren en su conjunto representaría la cadena del polímero.
Una sola cadena del polímero de Kevlar podría tener desde cinco hasta un millón de
monómeros enlazados juntos. Cada monómero de Kevlar es una unidad química que
contiene 14 átomos de carbono, 2 átomos de nitrógeno, 2 átomos de oxígeno y 10 átomos
de hidrógeno.
Químicamente se puede representar un monómero de Kevlar como esto:
El Kevlar es una poliamida, en la cual todos los grupos amida están separados por
grupos para-fenileno, es decir, los grupos amida se unen al anillo fenilo en posiciones
opuestas entre sí, en los carbonos 1 y 4. El Kevlar se muestra en la figura grande, en la
parte superior de esta página.

16. El Nomex, por otra parte, posee grupos meta-fenileno, es decir, los grupos amida se
unen al anillo fenilo en las posiciones 1 y 3.
Las aramidas se utilizan en forma de fibras. Forman fibras aún
mejores que las poliamidas no aromáticas, como el nylon 6,6.
Las cadenas del polímero se pueden juntar aleatoriamente o se pueden
orientar cuidadosamente de lado a lado en una fila. Resulta que la
orientación de las cadenas del polímero es muy importante para ciertas
características tales como flexibilidad, rigidez, y fuerza.
Una fibra de Kevlar es un arsenal de moléculas orientadas en paralelo como un paquete
de espaguetis crudos. Esta colocación espacial es lo que proporciona las moléculas con
estructura cristalina. La cristalinidad es obtenida por un proceso de fabricación que
implica sacar la solución fundida del polímero a través de agujeros pequeños de la
extrusora. La cristalinidad de los filamentos del polímero de Kevlar contribuye
perceptiblemente a su fuerza y rigidez únicas.

17. ¿Cómo son realmente las moléculas de Kevlar?
Una resistencia excepcional.
IR
Las amidas tienen la capacidad de adoptar dos formas diferentes, o conformaciones.
Usted puede ver ésto en la figura de una amida de bajo peso molecular. Las dos figuras
son del mismo compuesto, en dos conformaciones diferentes. La que está a la izquierda
se denomina conformación trans, y la que está a la derecha conformación cis.
En latín, trans significa "del otro lado". Así, cuando las cadenas hidrocarbonadas de la
amida están en lados opuestos al enlace peptídico, el enlace entre el oxígeno del
carbonilo y el nitrógeno de la amida, ésta se denomina amida trans. Asimismo, cis en
latín significa "en el mismo lado", y cuando las cadenas hidrocarbonadas están del
mismo lado del enlace peptídico, la llamamos amida cis.

18. La misma molécula de la amida puede torcerse hacia adelante y hacia atrás entre las
conformaciones cis y trans, originando una pequeña energía.
En las poliamidas también existen las conformaciones cis y trans. Cuando en una
poliamida todos los grupos amida están en su conformación trans, como el nylon 6.6 por
ejemplo, el polímero se estira completamente en una línea recta. Esto es exactamente lo
que deseamos para las fibras, porque las cadenas largas y completamente extendidas se
empaquetan más adecuadamente, dando lugar a la forma cristalina que caracteriza a
las fibras. Pero lamentablemente, siempre existen unos pocos enlaces amida en la
conformación cis. Por ello las cadenas del nylon 6.6 nunca llegan a estar completamente
extendidas.

19. Sin embargo el Kevlar es diferente. Cuando intenta adoptar la conformación cis, los
hidrógenos de los voluminosos grupos aromáticos se interponen en el camino. La
conformación cis coloca a los hidrógenos un poco más cerca de lo que quisieran estar.
De este modo, el Kevlar permanece casi enteramente en su conformación trans. Y así,
puede extenderse completamente para formar unas hermosas fibras.

20. Veamos ésto en un primer plano. Observe la figura de abajo y podrá apreciar que
cuando el Kevlar intenta adoptar la conformación cis, no queda espacio suficiente para
los hidrógenos de los fenilos. De modo que la conformación trans es la que se encuentra
generalmente.