Stephanie Kwolek was the unlikely DuPont chemist who invented Kevlar, the miracle fiber that's five times stronger than steel. Her invention has literally been a lifesaver.
Kevlar (poly-paraphenylene terephthalamide) is found in many places, including protective gear for police officers and soldiers. And it stops bullets. For instance, Marine Daniel Greenwald was conducting a routine stop at a vehicle checkpoint in Anwar Province, Iraq, when a sniper bullet struck him in the head in 2006. And it was Kevlar that lined Greenwald's helmet and diverted the bullet from its intended target.
The soldier owes his life to the life's work of Kwolek.
Cultivate Your Passion Like Stephanie Kwolek
Kwolek (1923-2014), the daughter of two Polish immigrants, was born in New Kensington, Pa., outside Pittsburgh. Her father was an amateur naturalist. And it was through him and their long walks in the woods that she developed her love of science. He taught her patience, how to observe and also to remember. Though they didn't realize it at the time, these were all tools that would serve her well as an adult.
Unfortunately, her father passed away when she was just 10. Her mother, a seamstress, valued precision and attention to detail, also qualities that would help her later. But a career in science was not on Kwolek's mind at the time.
She "didn't start out to be a chemist," she told an interviewer from the Science History Institute Museum and Library. "I was going to be a fashion designer, and that's what I did as a child. I spent hours drawing and so forth."
Kwolek: Sketch Your Future
Kwolek drew and designed dresses that her biographer, Edwin Brit Wyckoff, claimed were as good as the pictures in fashion magazines. Throughout grade school she brought them to life, sewing clothes for her dolls, with each stitch perfectly aligned.
But her mother thought Stephanie was too much of a perfectionist to succeed in clothes design, where that kind of rigidity can be less of an asset. Luckily, in high school Kwolek became fascinated by the chemistry lab, where her preoccupation with perfection was a definite asset. Mixing chemicals in exact amounts and observing the results reminded her of her long walks with her father watching spiders spin their webs.
So out went Paris and the catwalk. Instead, Kwolek decided on a career in medicine. The first step was attending the all-female Margaret Morrison Carnegie College (now part of Carnegie Mellon) to study chemistry. She couldn't immediately afford medical school, so she intended to work for a few years.
She applied for several jobs, including one at DuPont, a chemical company. At the conclusion of her interview there, she was told by W. Hale Church, the company's research director, that she would hear back in a few weeks.
Keep Seeking Answers
But Kwolek wasn't satisfied with that answer. So, as she said in the Science History Institute interview, very politely, but "with great boldness — I would never do it now — I said to him, 'I wonder if you could possibly tell me sooner, because there's another company that wants me to decide whether I should come and work for them.'"
To contemporary ears, that doesn't quite measure up to "great boldness." But this was 1946, when women in the workforce were rare and women in science were ever rarer. In any case, it sufficiently impressed Church, who called in his secretary and "dictated the letter to me while I was standing there and offered me the job," Kwolek said.
She believed that it was her assertiveness that landed her the position.
Kwolek was charged with helping the company develop fibers made from chemicals, synthetics that were typically stronger, warmer and cheaper than nature could make them. Just years earlier, for example, the company had developed nylon. In the years ahead, she helped invent fibers such as Nomex (a flame-resistant nylonlike material used on fire fighters' turnout gear, and aided the development of Spandex. Kwolek worked at DuPont for more than four decades.
Jump On Opportunities Like Kwolek
But Kevlar was the innovation Kwolek is best known for. In the early 1960s, DuPont began a project to find a new high-performance fiber that could be used to reinforce car tires.
The work involved manipulating strings of carbon-based molecules to produce a longer chain of molecules called polymers, and then running the solution through a machine that would spin it into a fiber. At the time, the molecules DuPont worked with had to be melted at nearly 400 degrees Fahrenheit, but that made the fibers too weak and floppy for the job. Kwolek had to find a polymer that could be spun at lower temperatures.
It was a hit-and-miss operation along the lines of Thomas Edison's search for the perfect lightbulb filament. The team produced thousands of liquid fibers, but none as stiff and strong as steel.
Frustrated, many chemists quit the project. But the patience Kwolek learned from her father kept her in the race and ultimately paid off.
Strive To Do Hard Things
One batch Kwolek produced seemed an anomaly. Normally, the dissolved polymers produced a clear, syrup-thick solution. But one was milky and runny. It intrigued her, and she continued working with it. "I made a discovery," Kwolek told reporters at the time.
The polymer chain looked "like spaghetti lined up next to each other. Anyone who wasn't thinking would have thrown it out," she said. "I seem to see things other people do not see. You have to have an open mind."
She sent the mixture to the spinning room to be spun into threads. But as she recalled it, "the guy in charge of spinning refused to spin the liquid." He was afraid it would gum up his equipment. But Kwolek refused to take no for an answer.
She asked him again the next day. And then the day after and the day after that for several days. "Either I wore him down or he felt sorry for me," she said.
During the spinning, an unusual reaction occurred. The links that looked like spaghetti lined up next to each other in a perfect formation and created a thread nine times stronger than had ever been created before.
Kwolek: Be Patient For Success
It took about five years before the first Kevlar products went on the market. Now it's found in everything from automobile brake pads to skis, skateboards and snowboards.
Kwolek never directly profited from her multibillion-dollar invention. And she retired from DuPont in 1986. But she remained as a consultant and won numerous awards for work, including induction into both the National Inventors and National Women's Halls of Fame. President Bill Clinton awarded her the National Medal of Technology. She also was the first woman to win DuPont's Lavoisier Medal in 1995.
With typical modesty she said, "I feel very humble. I feel very lucky. So many people work all their lives and don't have a big break."
After her retirement, Kwolek tutored high school students across the country in chemistry, concentrating on preparing young women for work in the sciences. She also developed a scientific demonstration called the nylon rope trick that demonstrates the preparation of a synthetic polymer at room temperature. It is still used in classrooms today.
Kwolek's Keys:
- Invented the Kevlar fiber as a longtime chemist at DuPont.
- Overcame: Reluctance to share her findings on the fear that test results were wrong.
- Lesson: "I didn't want to be embarrassed. But when I did tell management, they didn't fool around. They immediately assigned a whole group to work on different aspects of the material."
