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How One Woman’s “Failure” Created a New Industry

Elizabeth Sindelar-Loy – July 5, 2022

“I guess that’s just the life of an inventor: what people do with your ideas take you totally by surprise.”

As Stephanie Kwolek looked down at the odd, opaque solution, she thought her experiment had hit another dead end. However, to her astonishment and her colleagues, this unusual mix of polymers proved to be one of the most significant scientific discoveries of the 21st century. The polymer solution Stephanie thought to be a total failure created incredibly strong fibers after being spun. It was unlike anything ever seen before. Kwolek had inadvertently invented a heat-resistant plastic that was five times stronger than steel. Yet, it was lightweight and tough enough to stop bullets and knives – she had discovered Kevlar®

The year was 1965, when Kevlar® was invented in the DuPont laboratory. The company had foreseen the gasoline shortage of 1973 and tasked a team to develop a superior material to be used in automobile tires that could improve gas mileage. They were on a mission to develop light, strong, rigid fibers to replace the steel wires that were being used in tires.

alt="Stephanie Kwolek"

Stephanie Kwolek, a Polish American chemist, was the only female team member and possessed just a mere bachelor’s degree. Her childhood dream was to become a doctor, but she also loved sewing and science. Kwolek graduated from the women’s college of Carnegie Mellon University with a degree in chemistry but, her overall goal was to pursue a doctorate degree.  Needing funds for medical school, Kwolek sought out a chemistry job at DuPont.  While there she began experimenting with polymers.  It combined her lifelong love of fabrics and science which led to her incredible discovery.  What originally was a temporary stepping-stone to medical school turned out to be a lasting career for Kwolek at DuPont.

In the lab, Kwolek would dissolve long chains of molecules called polyamides and then run the solution through a machine that would spin it into fibers. Polyamides are the same type of synthetic polymer used to make materials like nylon. Initially, DuPont was working with molecules that had to be melted at nearly 400 degrees Fahrenheit to be spun. This made the fibers too weak and floppy for durable tires. Defeated, the team tasked Kwolek with finding a version that could be spun at low temperatures in effort to achieve their goal.

Kwolek analyzed her experiments and found a specific formation of molecule chains that was exceptionally tough and rigid.  The polyamide solution created was unusually smooth, cloudy, and buttermilk-like in appearance. This solution became opalescent when stirred and was incredibly different from nylon polymers which are clear and thick. 

When Kwolek asked the solution to be spun, the person in charge of the equipment initially refused. He thought the solution’s cloudiness was due to particles that would plug the spinneret’s tiny holes. After some persuasion, the solution was spun and to everyone’s surprise, strong, stiff fibers were made without difficultly.  From this discovery, many fibers were spun from the liquid crystalline solution, including the yellow Kevlar® fiber.

This amazingly powerful fiber is the vital component behind lifesaving bulletproof vests and helmets. The strength of Kevlar® is so versatile it is used in spacecrafts, planes, boats, canoes, automobiles, shoes, luxury fashion. Kevlar® is also in fiber optic cables that allows the world to connect to the internet.

Specifically in vehicles, Kevlar® has been used in bodywork, vehicle armor, hoses, belts, gaskets, tires, clutches, and brake pads.  When steel, aluminum and rubber is mixed with Kevlar® fibers, they become lightweight, stronger, and more resistant to wear and tear.  It does make automobile parts more expensive which is why Kevlar® is used in military, luxury, and race cars as opposed to daily drivers.

After the discovery of Kevlar®, Stephanie Kwolek headed polymer research at DuPont’s Pioneering Lab until her retirement in 1986.  Among all the accolades she earned for her achievements, Kwolek was inducted into the National Inventors Hall of Fame (1994) and was awarded the National Medal of Technology (1996) and the Perkin Medal (1997).  Even by today’s standards these are all rare honors for a woman to receive.  In 2003, she was inducted into the National Women’s Hall of Fame. Stephanie was also an advocate for women in science mentoring other female scientists and participating in programs that introduce young children to the field.  She passed away at the age of 90 leaving behind a legacy that has forged a path for women in science, as well as the automobile industry.

Post by Kim Althage
July 5, 2022