Kevlar fiber was developed by DuPont in 1965 as a replacement for steel in racing tires. It is a high-strength synthetic fiber made from polymers that are spun into a liquid crystal and oriented along the fiber axis. Kevlar is produced through a condensation reaction of 1,4-phenylene-diamine and terephthayal chloride, resulting in a liquid crystalline polymer solution that is spun through a spinneret into a bath to form fibers. Kevlar fibers have high strength and stiffness but also absorb moisture, and are difficult to cut, making production expensive. Its properties make it useful in applications requiring strength and impact resistance such as body armor, cables, and sports equipment.

1. Kevlar Fiber
• Rizwan Younis

2. Introduction
• Developed by Stephanie Kwolek at DuPont in
1965, this high-strength material was first
commercially used in the early 1970s as a
replacement for steel in racing tires.
• According to FTC;
• Manufactured high-modulus fiber in which the
fiber-forming substance is a long-chain synthetic
aromatic polyamide in which at least 85% of the
amide linkages are attached directly to aromatic
rings.

3. Formula

4. Raw Material
• 1,4-phenylene-diamine
• Teraphthalyal Chloride
• N-methyl-pyrrolidone
• Calcium chloride
• Sulphuric Acid

5. Kevlar

6. Production
• 1,4-phenylene-diamine (para-
phenylenediamine) and terephthayal
chloride react in a condensation
reaction yielding hydrochloric acid as a
byproduct.
• The result has liquid_crystalline behavior.
• mechanical drawing orients the polymer
chains in the fiber's direction

7. Production
• Viscous polymer is obtained
• Polymer is disloved in N-methyl-pyrrolidone or
calcium chloride.
• It is also treated with concentrated sulfuric
acid, needed to keep the water-insoluble
polymer in solution during its synthesis and
spinning.
• This makes its production expensive

8. Spinning
• A hot, concentrated, and very viscous solution
treated with sulphuric acid is forced through a
spinneret into a aqueous coagulating bath,
with an air gap separating the spinneret from
the bath.
• The fiber is than washed thoroughly with
water and dried.

9. Spinning
• The fibers are then cut to length and woven
into a tough mat to make the super-strong,
super-stiff finished material we know as
Kevlar.

10. Spinning

11. Properities
• Light weight
• Very good tempareture resistence
• Upto 450 centidegreegrade
• Resistence to almost all type of chemicals
• Immense strength
• Negative cofficient of thermal expansion
• Abrasion resistence

12. Properties
• Nonconductive under regular conditions, but
can absorb water and salt water.
• Sensitive to shock load. Can fail unexpectedly
if subject to shock.
• Sensitive to degradation from ultraviolet
radiation.
• Kevlar is quite stiff and has low stretching at
break.

13. Comparison
Advantages
• High strength to weight
ratio
• Impact resistence
• Abrasion resistence
• Don’t expand on heating
Disadvantages
• Absorbs moisture
• Poor
compressive strength
• Difficult to cut and
drill

14. Application
It has application wherever you need strength
It has application in following areas;
 Industrial Equipments
 Sports equipment
 In Military
 Safety equipments
 Musical instruments
 Music

15. Application
Due to its great strength it has huge application
its strength combined with light weight makes
it very popular fiber