Stephanie L. Kwolek (1923-2014), Chemist and Inventor of Kevlar
- Created the first of a family of synthetic fibers of exceptional strength
- Worked on the team that took her creation from invention to product implementation; now this fiber—or some form of it—is used in at least 200 different applications, including bullet-resistant clothing
At a time when few women worked in industrial chemistry, Stephanie L. Kwolek became the inventor behind Kevlar, a virtually bulletproof fiber that has saved thousands of lives.
Stephanie Kwolek was born in New Kensington, Pennsylvania. Her father loved taking Stephanie and her siblings for nature walks, so early on the kids all acquired an interest in observation and scientific collection. Unfortunately, he died when Stephanie was only 10.
Her mother—a stay-at-home mother until that time–had to go to work to support the family. She provided a strong role model for her children.
Kwolek attended Margaret Morrison Carnegie College, what was then the women’s division of Carnegie Mellon University, where she became interested in chemistry and medicine. After graduation she intended to work and save money for medical school.
Started at Dupont
She interviewed at Dupont and soon found herself working in the company’s textile labs under research director W. Hale Charch. She loved the daily problem-solving of the job, and soon forgot about wanting to go into medicine.
Kwolek had been with Dupont for almost twenty years when she was assigned to be a part of a team scouting for the next generation of fibers that were lightweight and strong but could perform well under extreme conditions.
The country was preparing for a gas shortage and Dupont was hoping to come up with a textile that could replace the steel in radial tires and the bodies of cars and airplanes. If products like vehicle tires and car and plane bodies were lighter and strong, that would save on gasoline because the overall weight of the vehicle would be so much less.
The lab work itself involved experimenting with long molecules, called polymers, that could be made into fabric or plastics. Each day chemists would test the molecules with various additives and applying different temperatures. One day Kwolek came up with something that was quite different—much thinner—than what usually resulted.
The polymers always had to go through a spinner as part of the process, and her substance was so different that the fellow in charge of the spinneret (the machine that was used to remove liquid solvent and leave behind fibers) refused to spin it, fearing it would clog the machine.
Kwolek had experimented with the substance and felt he was mistaken, so after several days of discussion, she finally wore the fellow down—he agreed to spin it. The result was a light but extremely strong fiber.
Forming a Team
When the lab realized what Kwolek had accomplished, the word spread to upper management at DuPont who put together a team of people to work with the scientists to identify and develop a market for what became known as Kevlar.
In an interview for the Lemelson Center (Smithsonian), Kwolek points out that to bring an invention to market requires many minds thinking of ways it can be used, and many hands accomplishing the work. Kwolek also stressed that even with team work, there were still days when all of them became discouraged and feared that nothing would come to pass from her invention.
Eventually of course, Kwolek’’s discovery was extremely useful. Variations on the fiber have been used in fiber-optic cable, fuel hoses, radial tires, special ropes, tennis rackets, canoes, and skis as well as huge items like parts of airplanes, and space craft.
The most famous application of Kevlar is used to create bullet-resistant vests, coats, and shirts as well as cut-resistant gloves. It took almost ten years from its invention to the date on which a bullet-proof product was created. By 1975 DuPont had developed its use within vests, and in 1975 the first were made available to police departments. A vest made of seven layers of the fibers weighs just 2.5 pounds and can deflect a knife blade and stop a .38 caliber bullet shot from a distance of ten feet. Today these vests are reinforced with ceramic plates to withstand rifle fire.
At the time of her death in 2014, it was estimated that the product helped save thousands of lives.
Kwolek retired from DuPont in 1986 but continued to consult for them for many years. She also spent time tutoring high school students in chemistry, paying particular attention to grooming young women to work in the field.
She has received many honors for her accomplishments. In 1995 she became the fourth woman added to the National Inventors Hall of Fame. In 1996 she received the National Medal of Technology, and in 2003 she was added to the National Women’s Hall of Fame.
To learn about other remarkable women, read about Margaret Knight, the inventor of the brown paper bag; Marjorie Stewart Joyner, the inventor of hair-straighter/hair-curler machine; or Beulah Louise Henry, an inventor with 49 patents.