The History of Kevlar

Stephanie Kwolek's Research Led to the Development of Kevlar

Loom weaving kevlar fabric in carbon fibre factory
Loom weaving Kevlar fabric in a carbon fiber factory.

Monty Rakusen / Getty Images 

Stephanie Kwolek is truly a modern-day alchemist. Her research with high-performance chemical compounds for the DuPont Company led to the development of a synthetic material called Kevlar which is five times stronger than the same weight of steel.

Stephanie Kwolek: The Early Years

Kwolek was born in New Kensington, Pennsylvania, in 1923, to Polish immigrant parents. Her father, John Kwolek, died when she was 10 years old. He was a naturalist by avocation, and Kwolek spent hours with him, as a child, exploring the natural world. She attributed her interest in science to him and an interest in fashion to her mother, Nellie (Zajdel) Kwolek.

Upon graduating in 1946 from the Carnegie Institute of Technology (now Carnegie-Mellon University) with a bachelor's degree, Kwolek went to work as a chemist at the DuPont Company. She would ultimately obtain 28 patents during her 40-year tenure as a research scientist. In 1995, Stephanie Kwolek was inducted into the National Inventors Hall of Fame. For her discovery of Kevlar, Kwolek was awarded the DuPont company's Lavoisier Medal for outstanding technical achievement.

More About Kevlar

Kevlar, patented by Kwolek in 1966, does not rust or corrode and is extremely lightweight. Many police officers owe their lives to Stephanie Kwolek, for Kevlar is the material used in bulletproof vests. Other applications of the compound — it is used in more than 200 applications — include underwater cables, tennis rackets, skis, airplanes, ropes, brake linings, space vehicles, boats, parachutes, skis, and building materials. It has been used for car tires, firefighter boots, hockey sticks, cut-resistant gloves, and even armored cars. It has also been used for protective building materials such as bombproof materials, hurricane safe rooms, and overtaxed bridge reinforcements.

How Body Armor Works

When a handgun 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 vest from the bullet, causing the bullet to deform or "mushroom." Additional energy is absorbed by each successive layer of material in the vest, until such time as the bullet has been stopped.

Because the fibers work together both in the individual layer and with other layers of material in the vest, a large area of the garment becomes involved in preventing the bullet from penetrating. This also helps in dissipating the forces which can cause nonpenetrating injuries (what is commonly referred to as "blunt trauma") to internal organs. Unfortunately, at this time no material exists that would allow a vest to be constructed from a single ply of material.

Currently, today's modern generation of concealable body armor can provide protection in a variety of levels designed to defeat most common low- and medium-energy handgun rounds. Body armor designed to defeat rifle fire is of either semirigid or rigid construction, typically incorporating hard materials such as ceramics and metals. Because of its weight and bulkiness, it is impractical for routine use by uniformed patrol officers and is reserved for use in tactical situations where it is worn externally for short periods of time when confronted with higher-level threats.​

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Bellis, Mary. "The History of Kevlar." ThoughtCo, Aug. 27, 2020, Bellis, Mary. (2020, August 27). The History of Kevlar. Retrieved from Bellis, Mary. "The History of Kevlar." ThoughtCo. (accessed June 3, 2023).