Kevlar, a synthetic fiber developed by DuPont in 1965, is known for its extraordinary strength and light weight, being five times stronger than steel. It is produced through a specific chemical synthesis and is utilized in various applications including industrial equipment, sports gear, personal protective equipment, and military gear. Despite its advantages, Kevlar has limitations such as low compressive strength and sensitivity to environmental factors.

1. KevlarFiber
Presented by
Devansh Gupta
M.Sc Polymer Science
Semester 1

2. Contents
 Introduction
 History
 Chemical Reaction
 Production
 Structure & Properties
 Advantages
 Disadvantages
 Applications
 Reference
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3. Introduction
 It is DuPont’s registered trademark for para-aramid synthetic fiber
which is made by combining para-phenylenediamine(PPD) and
teraphthaloyl chloride(TCl).
 Kevlar has not been around for very long. Stephanie Kwolek
who worked for DuPont made Kevlar in 1965 to manufacture a
stronger tire. Instead of revolutionizing the tire industry, Kevlar
revolutionized the entire world.
 It is a fiber that when woven together has the five times strength of
steel.
 Kevlar was first commercially used in early ‘70s as a replacement of
steel in racing car tires.
 Typically it is spun into ropes or fabric sheets that can be used direct
or as an ingredient in composite material components.
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4. History
 In 1964, her group began searching for a new lightweight strong
fiber to use for light but strong tires. The chemicals she had been
working with at that time, formed liquid crystals while in solution,
something unique to those polymers at the time.
 The solution was cloudy, opalescent upon being stirred, and of
low viscosity and usually was thrown away. However, Kwolek
persuaded the technician, Charles Smullen, who ran the "spinneret",
to test her solution, and was amazed to find that the fiber did not
break, unlike nylon.
 After Kwolek discovered Kevlar, she was not very involved in
developing the applications of Kevlar.
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5. Chemical Reaction
 Kevlar is synthesized in solution from the monomers para-
phenylenediamine(PPD) and terephthaloyl chloride(TCl) in a
condensation reaction in which molecules of HCl are terminated as a
byproduct.
 Hexamethylphosphoramide
was the solvent initially used
for the synthesis, but for safety
reasons DuPont replaced it by
a solution of
N-methyl pyrrolidone and
CaCl .
-n HCl
n n
n2
10-20*C
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6.  Another substance which is involved in the synthesis of Kevlar is
highly concentrated sulphuric acid.
 It is used to keep the crystalline Kevlar in the solution while it spins
in the spinneret.
 It is very difficult to use highly concentrated sulphuric acid but it’s a
necessary process, that’s why it is one of the most expensive step of
production.
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7. Production
 The product obtained in the laboratory is turned into fibers by a
process called dry-jet-wet spinning; in which a hot and very viscous
solution of PPTA through a spinneret to make long, thin, strong, and
stiff fibers that are wound onto drums. The fibers are then cut to
length and woven into a tough mat to make the super-strong
material we know as Kevlar.
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8. Structure
When Kevlar is spun, the resulting fiber has a tensile strength of
about 3,620 MPa, and a relative density of 1.44 gm/cc.
 Presence of Amide linkages and other inter-chain bonds like
hydrogen bonds give this much high strength.
 The presence of salts and certain other impurities,
especially calcium, could effect the properties of Kevlar That’s why
care is taken to avoid impurities in its production.
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9. Advantages
 Strong but relatively Light weight.
 Tensile strength of Kevlar49 & Kevlar29 is over 8 times greater than
that of steel wire.
 Bear temperatures up to 450*C (No thermal shrinkage)
 No embrittlement found on very low temperature (-196*C).
 Kevlar can remain virtually unchanged after exposure to hot water
for more than 200 days.
 Kevlar can be ignited but burning stops when source removed.
 Resist attacks from almost all types of chemicals but long exposure to
strong acids or bases will degrade it .
 Low electrical conductivity.
 High cut resistance.
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10. Disadvantages
 Although Kevlar has very high tensile strength, it has very low
compressive strength. That’s why Kevlar can not replace steel as a
primary building material in structures like buildings & bridges
where compressive forces are required.
 Kevlar fibers quickly absorb moisture, meaning it is more sensitive to
its environment than other materials.
 It can be difficult to cut & drill. Specially made scissors are usually
required to cut the fabric.
 Kevlar reacts very badly to UV Light that’s why UV stabilizer is
required for outdoor applications.
 It suffers some corrosion if exposed to chlorine.
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11. Applications
Industrial applications
 Kevlar is used to make industrial equipment such as hoses, belts,
reinforcement materials. It is used to make parts of aircrafts, ship
hulls, reinforce tyres.
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12.  Kevlar is used as a reinforcement material for racing car tyres and
bicycle tyres. It helps to reduce puncture rate. Generally these tyres
are much more expensive than ordinary road tyres.
 The best example of Kevlar reinforced car tyre is American
President’s car “The Beast”. It’s tyres are so strong even a bullet can
not penetrate into it.
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13. Sports equipment
 Kevlar is used in making of various sports equipment due to light
weight and strength. These includes tennis, table tennis,
badminton, squash rackets, cricket bats and hockey sticks.
 F1 race car parts and body, sport shoes, snow boards, skate boards,
surf boards, gloves, racquets, motor sport helmets etc are also
madeup from Kevlar.
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15. Brakes
 Asbestos brake pads were initially used in vehicles but dust
produced from these brakes pads is toxic that’s why chopped
Kevlar fiber has been used as a replacement for asbestos in brake
pads.
Smart Phones
 The Motorola RAZR Family, The Motorola Droid Maxx and the
OnePlus 2 have a Kevlar back plate, chosen over carbon fiber due
to its less interference in signal transmission and resilience.
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16. Frying Pans
 Kevlar is sometimes used as a substitute for Teflon in some
non-stick frying pans.
Personal safety equipment
 Kevlar is used in production of various personal protection gear
such as riding shoe, helmets, industrial gloves, fire fighting
apparel, body pads etc.
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17. In manufacturing of Military Equipments
 Because of it’s light weight and high tensile strength Kevlar is used
in production of various Army gear such as Military helmets,
Vehicle Armors, Body Armors, Tactical Vests, Fighter Plane’s Wings
and other parts etc
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19. TypesOf Kevlar
Although Kevlar is main product, there are various other
grades of Kevlar produced
 Kevlar29 – In industrial applications such as cables, asbestos
replacement, brake linings and body armors.
 Kevlar49 - High modulus used in cable and rope products.
 Kevlar100 – Coloured version of Kevlar.
 Kevlar119- Higher elongation, flexible and more fatigue resistant.
 Kevlar129- Higher tenacity for ballistic applications.
 Kevlar AP- 15% lighter tensile strength than Kevlar29.
 Kevlar XP- Lighter weight resin and KM2 plus fiber combination.
 Kevlar KM2- Enhanced ballistic resistance for armor applications.
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20. Sci-fi Part
 While watching any Batman series Movie have you ever Thought
Without Any Superpowers Like Superman Or Wolverine How
Batman Fight with enemies without getting touched by a bullet??
 Just because his suit contains more than 50% Kevlar fiber which
provides him strength and thus he can avoid bullets like Peanuts..
 Due to Kevlar’s light weight Batman can easily jump or glide from
one building to another.
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22. How Bulletproof armor works??
 When a bullet strikes on bulletproof body armor, it is caught in a
web of very strong fibers. These fibers absorb and distribute the
impact energy of the bullet causing the bullet to deform like a
mushroom.
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23. Reference
 www.safeguardarmour.co.uk/articals/kevlar-uses
 Kevlarchemistry.neocities.org/about3.html
 www.safeguardarmour.co.uk/articals/ballistic-plates-summary
 www.wikipedia.org/wiki/Kevlar
 www.explainthatstuff.com/kevlar.html
 www.dupont.co.in/products-and-services/fabrics-fibers-
nonwovens/fibers/brands/kevlar/products
 www.technologystudent.com/joints/kevlar2.html
 Event-videek.blogspot.in/2015/03/power-wheels-obamas-beast.html
 P K Mallick -Fiber reinforced composites - Materials,
Manufacturing & Design-CRC Press 3rd Addition
 Manufactured Fibre Technology by V.B Gupta & V.K Kothari
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