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BGMEA University of Fashion and
Technology (BUFT)
Course Title: Textile Testing & Quality Control-II
Course Code: TEX3105
Assignment Name: Nomex Fiber
Group: 08 Section: 02
Assignment
Submitted to: Submitted by:
Shafat Ahmed Bin Kamal Id. 191-090-801
Lecturer, BUFT 191-091-801
Department of TE 191-093-801
191-097-801
191-098-801
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Nomex Fiber
Introduction:
Fiber and its properties are very important to the performance of the final textile products. High-
performance fibers are derived from their unique molecule and phase structures. Besides high
tensile strength and modulus, they may also have very high levels of other properties such as
operating temperature, heat resistance, flame retardancy, and chemical resistance. The concept
of high-performance fiber came into textile industries during 1950-1970’s. High performance
fibers have been developed to offer high strength, high modulus, thermal stability at high
temperature, chemical and solvent resistance and number of other properties for their own end
use application. Nomex is a one kind of high-performance fiber.
Nomex is an inherently flame-resistant, high-temperature resistant fiber that will not melt, drip,
or support combustion in air. It is offered in paper, felt, fabric, and fiber forms. Nomex is a
product of industrially-manufactured aromatic polyamide (aramid) fibers known to have
beneficial flame-resistant (FR) properties. The material has highly effective filtration and
insulation applications suitable for thermal protective apparel.
Fiber type: Synthetic fiber
Source: Aramid
Characteristics: Chemical resistant, Electrical resistant, Fire resistant
Typically used in: Glove, Trousers, Shoe, Shirt, Hood, Balaclava
Parent company: DuPont
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Nomex fiber is used across a diverse range of applications, but it is perhaps best known as a
critical component in protective apparel. Today, more than three million firefighters around the
world are protected by turnout gear, station wear and accessories made of Nomex for its unique
combination of flame protection, durability, and mobility. It also is used in apparel worn by
military pilots and combat vehicle crew; auto racing drivers, pit crew members and track officials;
and industrial workers at risk from flash fire and electric arc hazards. Some troops in Iraq are
being outfitted with Nomex flight suits to help protect them from burns caused by roadside
bombs, the greatest threat to American troops. Nomex fibers are instrumental beyond protective
apparel, as well. Motor, generator, transformer, and other electrical equipment manufacturers
have used DuPont Nomex, a standard for electrical insulation, for more than 40 years. Industries
from asphalt and cement plants to chemical and steel factories use filter media made of Nomex
brand fiber. Honeycomb of Nomex paper is used for lightweight structural support and helps
substantially improve the performance of commercial aircraft.
A Brief History of Nomex
Nomex was first created back in the early 1960s but would be marketed in 1967. Dr. Wilfred
Sweeney created it in the now world-renowned DuPont laboratory. Nomex’s technical name is
‘Synthetic Aromatic Polyamide Polymer’. This, in layman’s term, means that this is a material that
has been made in a lab.
The deaths in fiery crashes of race car drivers Fireball Roberts at Charlotte, and Eddie Sachs and
Dave MacDonald at Indianapolis in 1964, led to the use of flame-resistant fabrics such as Nomex.
In early 1966 Competition Press and Auto week 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." Wilfred sweeny the
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Dupont scientist responsible for discoveries leading to Nomex earned a Dupont Lavoisier medal
partly for this work in 2002. It sold in both fiber and sheet forms and is used in a fabric. Nomex
sheet is an actually a calendared paper and made in a similar fashion and made in <USA>.
Properties
The properties of Nomex include great electrical insulation properties at high
temperatures. Nomex does not flow or melt upon heating and doesn’t degrade or char at
temperatures until well over 370 degrees Celsius. The compound that is usually found in fire-
fighters coats and airline seat covers is Nomex III, which is a composite of 95% Nomex and 5%
Kevlar. The Kevlar adds stability and tear resistance to the material. The general properties of
Nomex are listed below.
➢ · Heat and Flame Resistant
➢ · High Ultraviolet Resistance
➢ · High Chemical Resistance
➢ · Low Thermal Shrinkage
➢ · Formable for Molded Parts
➢ · Low Elongation to Break
➢ · Low Electrical Conductivity
Nomex fiber is a member of the aramid family of fibers and is similar in appearance to nylon.
Fabrics woven of Nomex fibers are used in applications requiring good textile properties, good
dimensional stability, and excellent heat resistance.
Fabrics woven with Nomex fiber have a low level of flammability and do not melt or flow at high
temperatures. Above 700°F (370°C), they will degrade rapidly to a friable char. At the point at
which woven nylon fabrics melt (489°F, 254°C), fabrics woven of Nomex fiber retain about 60%
of their original strength. The flammability characteristics of fabrics woven of Nomex fibers do
not change with laundering. Fabrics woven of Nomex fiber have good resistance to many
chemicals and are highly resistant to most hydrocarbons and many other organic solvents. Their
acid resistance is superior to woven nylon fabrics. Fabrics woven of Nomex fibers exhibit good
resistance to alkalis at room temperature but degrade at high temperatures.
Compared to woven nylon fabrics, fabrics woven of Nomex fiber exhibit higher resistance to beta
and gamma radiation, to X-rays, and to water or steam at high temperatures. Therefore, fabrics
woven of Nomex fibers are excellent candidates for protective industrial apparel, aerospace
fabrics, and substrates requiring radiation resistance. These properties cause paper made by
Nomex to be stronger and tougher than regular cellulosic papers. Overall, Nomex is both
thermally and chemically very stable. The difference between Kevlar and Nomex is the location
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of the amide linkages on the aromatic ring. Those differences cause Nomex to a lower modulus
and tensile strength and a higher elongation and solubility in organic solvents.
Tensile and thermal properties:
Nomex shows essentially no embrittlement or degradation at cryogenic conditions
(temperatures as low as -320°F [-196°C]). At room temperature, the tensile properties are in the
same range as those of nylon and polyester, making it easily processed on standard textile
equipment. Typical room temperature stress-strain curves are shown in Figure 2.2.
Types of Nomex:
Type 430 Nomex:
Type 430 is a high crystallinity natural filament yarn of Nomex with higher strength and chemical
resistance than staple spun yarns. Type 430 is used where the aesthetics and properties of a
filament yarn are required. It is available in light deniers for textile applications or higher deniers
for rubber hose reinforcement applications. Type 430 is used in firefighters’ turnout gear, coated
fabrics, electrical insulation, radiator hoses and industrial laundry press covers.
Type 450 Nomex:
Type 450 is a naturally white staple fiber. It has higher crystallinity and strength than Type 455
and 462 fibers, and is sold as a 100% meta-aramid staple in various cut lengths. It is used in
applications requiring high tensile properties, as well as chemical and thermal stability, such as
in hot gas filtration fabrics, sewing threads, zipper tapes and firefighters' turnout facing fabrics.
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It is also used in its natural color for knit products such as balaclavas and underwear. Although
dyeable, it is less dyeable than the Type 455 and 462 staple products, and is not available as a
dye merged staple.
Type 455 Nomex (Nomex III):
Type 455 is a patented staple blend of Nomex and Kevlar fibers that was introduced to fill the
need for higher performance thermal protective apparel. When converted to fabric, Type 455
staple is known commercially as Nomex III. It offers several improvements compared to yarns or
fabrics produced from Type 450 staple. However, because of its lower crystallinity, it produces
yarn and fabrics that are slightly lower in strength than those produced from Type 450 staple.
Type 462 Nomex (Nomex IIIA):
Type 462 staple is a blend of Nomex and Kevlar fibers, and a proprietary static dissipative fiber.
When converted to fabric, it is known commercially as Nomex IIIA and is used for thermal
protective apparel. It offers all the features of Type 455 staple plus a higher level of static
dissipation in fabric form. The added antistatic fiber dissipates static generated from fabric-to-
fabric and fabric-to-surface rubbing; minimizes the contribution of clothing to static hazards; and
reduces apparent electric field strength and nuisance static. The staple is dye mergeable and can
be package dyed as yarn for use in knit goods or sewing threads, or piece dyed as fabric for civilian
protective apparel. Except for the static dissipative properties of Nomex IIIA, all other properties
are essentially the same as for Nomex III. Properties reported in this guide should be considered
applicable to both, unless a specific difference is noted in the text.
Type N101 and N102 filament yarn:
Producer-colored filament yarn is available in a range of colors and deniers. Type N101 is
entangled and Type N102 is a texturized filament yarn.
Type N104 dyeable filament yarn:
Type N104 is a low crystallinity filament yarn available for applications where a dyed yarn is
required. It dyes similarly to Types 455 and 462 Nomex. Shrinkage of 7% to 8% may make package
dyeing difficult.
Type N300
The N300 series is a producer-colored staple fiber type primarily used for protective apparel. This
variety contains a mixture of Kevlar and Nomex fibers for up to 2 inches (depth) of material
availability. It is also equipped with moisture barriers when applied as apparel liners.
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Protera:
Protera is dominated by Nomex and Kevlar materials mixed with other types of fabrics. This is
specifically designed for protection against electric arcs, flash fires, and excessive washing.
Nomex MHP:
Nomex MHP is a proprietary blend of 34% aramid, 33% lyocell, 31% modacrylic and 2% antistatic
fibers. Nomex MHP provides inherent multi-hazard FR protection against heat and flame, electric
arc and small molten metal splash in a durable and comfortable fabric. Included antistatic fiber
dissipates static generated from fabric-to-fabric and fabric-to-surface rubbing; minimizes the
contribution of clothing to static hazards; and reduces apparent electric field strength and
nuisance static.
Nomex honeycomb:
Nomex honeycomb is made of Nomex paper, a form of paper made of aromatic polyamide -
aramid- fibers. Nomex paper provides high electrical, mechanical and chemical integrity,
moisture insensitivity, radiation and flame resistance. These unique characteristics make it the
perfect solution for many applications, especially those which need to be lightweight and fire
retardant.
An initial unstable expanded paper honeycomb structure is dipped into phenolic resin to produce
a honeycomb core which (after cure) becomes very strong. Subsequent dipping cycles can
increase strength and weight of the resulting product. Honeycomb cells can also be filled with
Fibermax Composites 2 component rigid foam for greater bond area for the skins. This
manufacturing technique increases the mechanical properties of the core by stabilizing the cell
walls and increases thermal and acoustic insulation properties.
The behavior of the honeycomb structures is orthotropic; hence the panels react differently
depending on the orientation of the structure. Therefore, it is necessary to distinguish between
the directions of symmetry, the so-called L or ribbon direction and W or transverse-to-ribbon
direction. The shear modulus and strength in the L direction are roughly twice than this in the W
direction.
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The manufacturing process:
Fibermax Composites honeycomb is manufactured by the expansion method which is a quite
simple process. Honeycomb starts out as flat sheets of Nomex paper material. Strips of adhesive
are “printed” on the Nomex paper in a staggered pattern. Next, the sheets of paper are stacked
together and cured to form a “HOBE” (honeycomb before expansion) block. The HOBE is pulled
apart from its sides (or “expanded”), much like an accordion, forming an expanded honeycomb
block, that now incorporates the hexagon cell shapes. This initially unstable expanded paper
honeycomb cell structure is dipped into phenolic resin. Once cured, the blocks are cut to the
honeycomb sheets with the desired thickness.
Cell Configuration:
Honeycomb can be made and cut to the standard hexagonal style which is and the most
common cellular configuration, or it can be over-expanded in the W direction to form the
corrugated or over-expanded (OX) configuration, where the cells look rectangular. The OX
process tends to increase W sheer properties and slightly reduce L shear properties compared
to hexagonal honeycomb core. There are also other configurations that Fibermax Composites
can design depending customers specific needs.
Production Process:
Nomex is produced by a condensation reaction from m-phenylenediamine and isophthaloyl
chloride. It is generally made in the USA and Spain.
The general process of creation is as follows:
1) Floe (short fibers) and fibrids (binding particles) are dry-spun in hot air
2) Fibers are put in a water-based mixture to remove CaCl2 (used to retain polymer in previous
steps)
3) The new mixture is turned into paper (it is chemically bonded & densified)
4) The material is drawn in steam to 5-6x its original length
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5) Clothing is cut from this material and stitched using Nomex thread
6) Voila!
Nomex can be produced as a continuous filament yarn, staple, spun yarn, floc, pressboard, paper,
needle felt, or as a fabric. This means there are multiple methods of production. However, it is
always created from the same condensation reaction.
Nomex in a spinning machine
Molecular structure of Nomex
Nomex is a meta-aramid fiber created by DuPont in 1961. The chemical name of Nomex is poly
(m-phenylenediamine isophthalamide), which is produced from the reaction of m-
phenylenediamine and isophthaloyl chloride whose structures are shown below.
Fig: Chemical Structure of Nomex Fiber
The solution is dry spun through spinnerets. The remaining solvent is evaporated, the filament
is washed and wound into tow, heated, and finally stretching into rolls at a temperature of 150
degrees Celsius. Nomex can be produced as a continuous filament yarn, staple, spun yarn, floc,
pressboard, paper, needle felt, or as a fabric.
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It is a long chain polyamide where at least 85% of the amide linkages are attached directly to two
aromatic rings. The meta-oriented phenylene forms bends in the polymer chain, reducing chain
rigidity as compared to the para orientation in the chemically similar Kevlar para-aramid chain.
This flexible polymer chain gives Nomex more textile-like qualities while retaining high-
temperature properties similar to Kevlar. The aromatic rings and the conjugated amide bonds
that link them together are particularly strong and resistant to chemical attack. They also provide
a high degree of heat resistance to the polymer backbone. As a result, Nomex does not melt and
drip, and merely chars when exposed to high temperatures for prolonged periods.
Resistance to degradation
Abrasion:
Abrasion resistance is an important consideration in both protective apparel and filtration
applications. Abrasion from wear and laundering is a primary cause of garment failure, whereas
abrasion from dust exposure and cage wear often leads to filter bag failure. Woven fabrics made
from spun staple yarns of Nomex consistently exhibit abrasion resistance superior to that of
comparable, or in some cases, even heavier constructions of polyester/cotton blends and 100%
cotton.
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Chemical resistance:
In general, Nomex fiber exhibits very good resistance to many chemicals. It is highly resistant to
most hydrocarbons and organic solvents. Chemical resistance during exposure in use and to
chemicals and solvents used in cleaning contributes to the excellent durability and wear life of
garments made of Nomex.
Acid resistance:
In general, Nomex fiber exhibits very good resistance to many chemicals. Materials that do attack
Nomex are strong acids, strong alkalis and/or strong oxidizing agents. Water vapor is also
necessary for activation of the degrading reactions; thus, care must be used in estimating
performance when the moisture level is unknown or uncontrolled. Frequently, reduced filter life
occurs due to acid attack when gases containing sulfur dioxide or trioxide are filtered. If acid
attack is a possibility, or flue gas components are unknown, filter bags made of Nomex should be
tested prior to installation.
Temperature resistance:
The maximum continuous operating temperature recommended for Nomex is 400°F (204°C). If
temperature surges above this limit are expected on a frequent basis, it may be necessary to
adjust the average operating temperature downward to extend filter bag life.
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Vapors:
The resistance of Nomex to degradation by vapors is an important consideration in hot gas
filtration applications (depending on their concentration in the gas stream). Acidic gases such as
HCl, SO2 and NOx can significantly reduce the service life of filter bags made of Nomex. Organic
vapors generally have little effect on Nomex.
UV light:
Like other natural and synthetic textile materials, most types of Nomex are impacted by
prolonged exposure to ultraviolet (UV) radiation from both sunlight and artificial light sources.
The absorption spectrum of Nomex overlaps with the energy spectrum produced by natural
sunlight in the near-UV and lower visible regions. Nomex absorbs its maximum energy at the high
end of the UV spectrum (approximately 360 nanometers), where the relative intensity of the UV
component of most light sources is greatest. The strength loss that accompanies UV exposure
has no effect on the inherent thermal properties of Nomex.
Radiation:
Nuclear power plants and other high-energy radiation operations often require the use of fiber
products capable of withstanding the deteriorating effects of gamma and UV radiation. The
outstanding resistance of Nomex to degradation by such radiation is illustrated by the data
shown in Table II-5. Nomex does not, however, provide protection against radiation.
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Application Information
Applications overview: Because of its excellent physical and thermal properties, Nomex fiber is
used in a wide variety of applications, including industrial coated fabrics; ironing- or pressing-
machine covers; rubber hose reinforcement; felt scrims; and the three leading applications—
thermal protective apparel, filtration and thermal resistant furnishings.
Firefighters
Because of its unique combination of textile and thermal properties, Nomex is used in a broad
range of thermal protective apparel applications wherever the risk of a fire or electric arc
exposure is present. 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
We have made a small reference to this already, but race car drivers wear suits that have Nomex
fiber material laced into their suits. This is because of the accidents that are involved in car racing,
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along with the flames that can arise from these dangerous and near-fatal car crashes.
Electric Conductive Suit
As mentioned already, Nomex is a multi-faceted material. The same molecular properties that
stop the flow of heat from engulfing firefighters and race car drivers in flames is the same
molecular structure that stops the flow of electricity as well. Nomex is an extremely poor
conductor meaning that this is an excellent insulator.
Aerospace Application
Much like Kevlar, in regards to the durability and lightweight appeal of this material, Nomex is a
great material to use in aerospace suits as well as in aviation uniforms. This lightweight, yet highly
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durable material, has also been used outside of just protecting people but also their living
environment.
Military use
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 use of Nomex in flash hoods and in Special Forces clothing was a great innovation; but the
use of Nomex is military gloves was the biggest move, brining Nomex to the military masses.
Nomex in gloves helps the modern soldier protect against flash burns caused by IED’s and
explosions and further protects the user against the fire caused by mine detonations etc.
The best-known aramids are Nomex, a high-melting fiber made into flame-proof protective
clothing, and Kevlar, a high-strength fiber made into bulletproof vests.
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Industrial Applications
Nomex is used in industrial applications as a filter in exhaust filtration systems, typically a
baghouse, that deal with hot gas emissions found in asphalt plants, cement plants, steel smelting
facilities, and non-ferrous metal production facilities.
Why we chose Nomex over other material:
Nomex is a flame-resistant material that is used in a wide variety of settings. Nomex material can
be found in the following applications: flight suits, military apparel, race suits, firefighting
apparel, automobiles, and many more. The reason that you will find this material in so many
applications is because of the benefits that it provides those industries. Below are 4 benefits of
choosing Nomex material over other available material.
Flame Resistance: The first and foremost benefit of choosing Nomex over other types of
materials is its flammability resistance. If you are involved in an industry and threat of fire or heat
can cause injuries to your employees then you want the best material at stopping both the heat
and flame itself. Nomex not only exceeds all major standards for flammability it also easily
outperforms other types of materials that are used in similar apparel. When compared to 100%
cotton or a Cotton/Polyester blend on a vertical flammability test, the Nomex material only chars
about 3 inches while both others char 12 inches. This clearly demonstrates that the Nomex is a
higher quality material and much more effective in stopping flames, thus resulting in safer
workers.
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Durability: When working in a field that requires this type of apparel it is critical that the apparel
is not only flame resistant but also durable. A product that only last a couple months is cost
prohibitive, regardless of the potential benefits. Products made with Nomex are durable and can
last up to five years when properly taken care of. This can be two to three times the lifecycle of
similar apparel made from different material.
Comfort: Despite its durability and flame-resistant qualities Nomex is extremely comfortable. Its
design allows it to have all of these qualities but still feel and act like traditional fabrics used in
these applications. It is also more lightweight than its traditional counterparts, adding to the
comfort to those who would wear this type of apparel. This comfort means that the apparel can
be worn on a daily basis, which also adds to the cost effectiveness of the product.
Ease of Care: Another great benefit of Nomex is how easy it is to take care of it. Unlike many
specialized materials used in these applications apparel made with Nomex can be washed either
at home, industrial laundry facilities or via dry cleaning. The ability to wash products made with
Nomex at a variety of facilities greatly increases its usability because it allows for the product to
be washed in any setting as opposed to more specialized materials which may need to be sent
out and cleaned, leading to down time and the need to have multiple pieces of apparel per
person. Again, this also adds to the cost effectiveness of this product.
Moisture regains and dimensional stability:
Moisture regain is the tendency of most fibers to pick up or give off ambient atmospheric
moisture until an equilibrium moisture content is reached. Relative humidity (RH) has a
significant effect on the rate of moisture absorption and equilibrium level. The higher the RH, the
faster Nomex absorbs moisture during the initial phase of moisture gain, and the higher the final
equilibrium level.
The effect of RH on the moisture regain of Type 430 Nomex is shown in Figure. When tested in
accordance with ASTM D2654 at 70°F (21°C) at 65% RH, fabrics of Nomex IIIA contain 5% to 5.5%
moisture at equilibrium levels. The moisture regain of Nomex is significantly greater than
polyester; slightly higher than nylon; and less than cotton.
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Effects of Nomex:
Nomex fibers are non-biodegradable and non-toxic to aquatic life; they pose no unusual
environmental hazard in a spill or fire. Fiber fly and dust may cause slight mechanical irritation.
May be harmful by inhalation (after often repeated exposure). May be harmful in contact with
skin (after often repeated exposure). Prolonged inhalation of respirable dust and respirable fiber
particulate at high concentrations can cause lung damage. Environment also affects the durability
of filter bags made of Nomex. In a highly acidic environment, it may be necessary to reduce the
average operating temperature to extend filter bag life. Nomex fiber is inherently flame resistant;
however, if combustible materials are collected on filter media of Nomex and exposed to an
ignition source, they can ignite and burn, resulting in destruction of the filter bag.
Nomex is untested for eye irritancy. As with other particles, mechanical action of fibers in the eye
may cause. Much like kraft paper, Nomex is also absorbent of moisture, so has to be combined
with other materials such as resins to ensure efficiency. Aramid materials are also difficult to cut
and grind without specialist materials. Due to this, Nomex insulation solutions can be more
expensive when compared to other solutions.
Effect of moisture:
The presence of small amounts of water vapor in air or other gases has no apparent effect on the
strength properties of Nomex, even at elevated temperatures. Variations in relative humidity
from 5% to 95% have virtually no measurable effect on the strength of Nomex at room
temperature.
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Effect of dry heat
Thermogravimetric analysis (TGA) of Type 455 Nomex (Figure 2.5) shows less than 10% fiber
weight loss up to approximately 752°F (400°C) in air or nitrogen. Rapid weight loss is seen at
temperatures above 800°F (~427°C). Thermal oxidation in air is time/temperature dependent.
Fabric scorching or charring can occur in as little as 30 seconds at 662°F (350°C) in air. Increasing
the temperature will decrease the time to form chart.
Effect of yarn twist:
Yarn twist has a significant influence on filament yarn properties. Benefits can be derived from
using the optimum twist for all load-bearing yarns. The influence of increasing yarn twist on
physical properties of Nomex filament yarns is shown in Figures 2.3 and 2.4 for 200-denier and
1200-denier Type 430 Nomex, respectively. This influence can be summarized as follows:
•Elongation increases.
•Initial modulus decreases sharply.
•Tenacity increases as twist increases for 200 denier yarns.
•Tenacity peaks at approximately 4 TPI then decreases with further twist for 1200 denier yarn.
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Ultimately the Nomex material has numerous benefits and this is why it is favored throughout
the various industries that utilize it. The next time you are looking for the various types of safety
apparel, be sure to check and see if the product has Nomex in it, it could very well make the
difference between walking away from an accident or suffering severe injuries. Nomex is used in
industrial applications as a filter in exhaust filtration systems, typically a baghouse, that deal with
hot gas emissions found in asphalt plants, cement plants, steel smelting facilities, and non-ferrous
metal production facilities.
