Kwolek, Stephanie Louise (1923-2014), an American researcher, was the inventor of Kevlar, a fiber five times as strong as steel. Kwolek did much of her research at the DuPont Company, a chemical company where she worked for 40 years. She retired in 1986, holding 17 single or joint patents. Kwolek later worked as a consultant to DuPont and to the National Academy of Sciences, which advises the U.S. government on scientific matters. In 1996, she received the National Medal of Technology, the highest prize for technological innovation in the United States.
Kwolek was born on July 31, 1923, in New Kensington, Pennsylvania. In 1946, she earned a Bachelor of Science degree from Margaret Morrison college, the women’s branch of the Carnegie Institute of Technology (now Carnegie-Mellon University). That year, Kwolek joined DuPont. Her team worked to create and test new polymers, long chain molecules created by linking smaller molecules. Polymers can be spun into fibers and made into fabric or plastics.
In 1964, DuPont asked Kwolek to find a strong, lightweight fiber to replace steel in reinforcing car tires. In 1965, Kwolek found such a polymer, eventually called Kevlar. The polymer’s molecules form liquid crystals when dissolved. When spun into solid fibers, the molecules line up facing the same direction. This structure gives the material extraordinary strength and stiffness.
By 1971, DuPont started commercial manufacture of Kevlar. Police officers began using Kevlar body armor in 1975. Protective vests made from multiple layers of Kevlar are lightweight but can stop many types of bullets. Kevlar has saved thousands of law enforcement officers from death or disabling injury. The U.S. military also adopted Kevlar body armor, helmets, and vehicle liners to reduce casualties in wars. Kevlar is also used in brake pads, motorcycle helmets, bridge cables, skis, airplane and spacecraft parts, belted tires, and other items. Kwolek died on June 18, 2014.
