Kevlar is a strong synthetic fiber made from aromatic polyamide. It was invented in 1965 by Stephanie Kwolek while working for DuPont. Kevlar has very high tensile strength despite its low weight, and is flame resistant, stiff, and resistant to chemicals and heat. It finds applications in body armor, helmets, vehicle armor, and other protective equipment due to its strength and impact absorption properties. Kevlar also has everyday uses such as in cell phone covers, apparel, ropes, tires, and fire-resistant materials.
2. Kevlar® Fiber
Kevlar® is a material formed by combining para-
phenylenediamine and terephthaloyl chloride. Aromatic
polyamide (aramid) threads are the result.
Kevlar was invented by Stephanie Kwolek while working
for DuPont in 1965 but commercial use began in 1971 .
3. Chemical Reaction
The reaction of 1,4-phenylene-diamine (para-
phenylenediamine) with terephthaloyl chloride yielding
Kevlar.
4. Advantages
High tensile strength at low weight
Flame resistant, self extinguishing
Low electrical conductivity
High chemical resistance
Excellent dimensional stability
Low thermal shrinkage
Low elongation to break
High toughness (work-to-break)
High cut resistance
High modulus (structural rigidity)
5. Disadvantages
1. Despite its strength and resilience, Kevlar also has some
disadvantages which limits its efficiency.
2. Kevlar fibers quickly absorb moisture, meaning it is more
sensitive to its environment than other materials.
3. Although Kevlar is strong its ability to cope with
compression is fairly poor. It can be difficult to cut.
Specially made scissors are usually required to cut the
fabric
6. Applications in Military
Vehicle Armor
Vehicle frame and body protection .
protects aircraft and helicopter crews.
Military Helmets
Absorb 20% more kinetic energy for Ground Troops
Improve mobility and fatigue of the solders because of
low weight.
Body Armor
Improved Outer Tactical Vest, ballistic, throat and groin
protectors, anti-mine boots and chaps.
16. HOW IT WORKS?
When a bullet strikes body armor, it is caught in a
“web” of very strong fibers. These fibers absorb and
disperse the impact energy that is transmitted to
the bullet proof vest from the bullet, causing the
bullet to deform or “mushroom.”