Kevlar is one of the most important manmade organic fibers ever developed. Because of its unique combination of properties, Kevlar is used today in a wide variety of industrial applications. Kevlar para-aramid fiber possesses a remarkable combination of properties that has led to its adoption in a variety of end-uses since its commercial introduction in the early 1970's.
Fibers of Kevlar consist of long molecular chains produced from poly-paraphenylene terephthalamide. The chains are highly oriented with strong interchain bonding which result in a unique combination of properties.
General Features of Kevlar:
- High Tensile Strength at Low Weight
- Low Elongation to Break High Modulus (Structural Rigidity)
- Low Electrical Conductivity
- High Chemical Resistance
- Low Thermal Shrinkage
- High Toughness (Work-To-Break)
- Excellent Dimensional Stability
- High Cut Resistance
- Flame Resistant, Self-Extinguishing
Kevlar is chemically stable under a wide variety of exposure conditions; however, certain strong aqueous acids, bases and sodium hypochlorite (chlorine bleach) can cause degradation, particularly over long periods of time and at elevated temperatures.
brand fiber, first developed in 1965, was the first material identified for use in the modern generation of concealable body armor. Kevlar is a manmade organic fiber, with a combination of properties allowing for high strength with low weight, high chemical resistance, and high cut resistance. Kevlar is also flame resistant; does not melt, soften, or flow; and the fiber is unaffected by immersion in water.
Kevlar 29, introduced in the early 1970s, was the first generation of bullet resistant fibers developed by DuPont and helped to make the production of flexible, concealable body armor practical for the first time. In 1988, DuPont introduced the second generation of Kevlar fiber, known as Kevlar 129. According to DuPont, this fabric offered increased ballistic protection capabilities against high-energy rounds such as the 9mm FMJ. In 1995, Kevlar Correctional was introduced, which provides puncture resistant technology to both law enforcement and correctional officers against puncture type threats.
The newest addition to the Kevlar line is Kevlar Protera, which DuPont made available in 1996. DuPont contends that the Kevlar Protera is a high-performance fabric that allows lighter weight, more flexibility, and greater ballistic protection in a vest design due to the molecular structure of the fiber. Its tensile strength and energy-absorbing capabilities have been increased by the development of a new spinning process.
Kevlar is best known for its application in the field of bullet-resistant personal body armor. But the applications for the lightweight and strength of Kevlar are many, and the list continues to grow.
Kevlar is an advanced technology from DuPont that helps transform ordinary products into extraordinary ones. It combines high strength with lightweight, and comfort with protection.
Kevlar is 5 times stronger than steel on an equal weight basis, yet, at the same time, is lightweight, flexible, and comfortable. It is this unique combination of attributes that enable those who use it to realize success, to perform to their fullest potential and to achieve their personal best.
In 1965, two research scientists working in a corporate lab created a remarkable fiber. The technology they developed was one that enhanced strength lightweight, and flexibility. It offered numerous other benefits—ones that could be offered in a variety of forms.
Kevlar, used in the plastic industry is categorized as an “aramid”, which is a special class of aromatic polyamides. This particular fiber is so tough that special equipment is required to cut the fiber so that it can be put to use. Some of the forms in which this strong fiber can be found are yarn, unwoven mats, and in some chopped fibers.
Kevlar is most widely used because of its toughness. It was first designed as a tread reinforcement on belted tires. Later it was designed for use with epoxy resins and as a reinforcement for laminates. Now Kevlar is being used for as a substitute for glass fabrics. Kevlar brand fiber quickly became the technology of choice for bullet-resistant vests. In fact, police officers have relied on the Kevlar brand for more than 25 years because of the superior bullet-stopping power it offers.
It is a very tough fiber and it is used today to make products, like bulletproof vest. The discovery of this product has made a big impact on people’s everyday lives.
Kevlar is a long chain-like molecule known as a polymer, which consists of repeating units called monomers. A Kevlar fiber is an array of molecules oriented parallel to each other like a package of uncooked spaghetti. This orderly, untangled arrangement of molecules is described as a crystalline structure. A manufacturing process known as spinning, which involves extruding the molten polymer solution through small holes, obtains crystallinity. The Crystallinity of the Kevlar polymer strands contributes significantly to Kevlar's unique strength and rigidity.
Kevlar is a polyaromatic amide. That is, it contains aromatic and amide groups. Other polymers with a high breaking strength often contain one or both of these molecular groups.
