Kevlar
Kevlar fiber is an innovative trademark of DuPont. Aramid (Kevlar) is a material invented in 1964 by Stephanie Kwolek, an American chemist, who worked as a researcher at the DuPont company.
Aramid is the abbreviation of the word aromatic polyamide. Aramid has a strong structure, tough (tough), have good damping properties (vibration damping), resistant to acids (acid) and bases (leach) and besides it can withstand heat up to 370 ° C, so it is not flammable.
Because it is so, Aramid is also used in the field of aircraft, tanks, and space (rockets) .The products are marketed known as Kevlar. Kevlar has a light weight, but five times stronger than steel.
With high technology that combines strength with light weight enough to help improve the performance of a variety of consumer products, industrial and military.
Lightweight and flexible is the nature of Kevlar, Kevlar has evolved over four decades of innovation.
composites
Composite is a combination of two or more materials that have different phase into a new material that has properties better than both. If this combination happens in macroscopic scale it is referred to as a composite
Kevlar Composite
One of the most well known use is the Kevlar bullet-resistant clothing in the body. Kevlar First introduced in the 1970s and is now used in a wide variety of products. Kevlar fiber itself has a high tensile strength, so it is desirable for the composite material.
Various kinds of grades of Kevlar Composites
Kevlar is now used in a wide variety of products fiber itself has a high tensile strength, making it very desirable for composite materials
There are three kinds of Kevlar used in composite materials. Kevlar 29 has a similar strength to the glass fiber with a lower weight, Kevlar and Kevlar 49 149 can be used to reduce the weight even more. Why not use Kevlar composite materials worldwide? Because the use of Kevlar fibers in the composite material is more expensive compared with other fibers such as glass.
The use of composite Kevlar certainly is taking into account in terms of the character of Kevlar material which is light, not heavy and strong. But the need to take into account in terms of costs and prices in the use of Kevlar material due to the use of Kevlar composites are more expensive than the use of other composite materials.
Based digunakkan Kevlar matrix including from the Polymer Matrix Composite
Polymer Matrix Composite (PMC):
The type of fiber used
• Glass fiber - fiber glass
• Carbon fiber - graphitic and amorphous C
• Aramid fiber - Kevlar, highly linear polymer chain
Matrix type commonly used
• Polyester and vinyl esters - fiberglass
• Epoxies - aerospace application, stronger, resistance to moisture
• Polimides - high temperature
• High temperature thermoplastic - PEEK <>
Advantages of PMC
• Lightweight
• Specific high stiffness
• Specific high strength
• Anisotropy
Application of PMC
• Bathroom furniture
• Aerospace
• Construction materials, etc
Advantages and Weaknesses
Kevlar advantages:
1. The power that is extraordinary (high enough) but light, even Kevlar 5x stronger than steel (in the same light weight and the same dimensions).
2. Kevlar material that has high tensile strength
3. Structure basically stable
4. Conduction of electricity is very low.
5. Resistance to the chemicals that are high enough.
6. Heat resistant and fire-resistant and low in bringing the heat.
Kevlar Weaknesses:
1. Price Kevlar fiber material is quite expensive
One example of Working Principle Shirt Anti bullet from Kevlar fiber
The principle works is to reduce as much as possible burst of kinetic energy of the bullet, by using layers of Kevlar to absorb the energy of the pace and break kepenampang comprehensive clothes, so that energy is not enough anymore to make the bullets can penetrate armor.
In the energy-absorbing rate of bullets, armor (Kevlar) deforms the pressing inwards (shock wave), this added pressure will be forwarded to the user's body.
Maximum limits emphasis added should not be more than 4.4 cm (44 mm).
If that limit is exceeded, then the clothes will be injured in the (internal organs injuries), which would endanger the safety of life.
