kevlar is a very strengthy fiber

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