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As a child,
she wanted to be a fashion designer. In college she wanted to be a doctor.
Stephanie Kwolek would end up making clothes, but not the kind she had
expected. She'd also end up saving lives, but not in a hospital. But more on
that in a minute.
Little kids are natural scientists, full of curiosity. Who among us never carried out experiments to study the effects of gravity on mashed potatoes, trying to determine if they fall at the same rate as scrambled eggs when dropped from the top of a high chair? Some kids are lucky enough to have parents who encourage their curiosity, and young Stephanie Kwolek was one of those kids. Her father was an amateur naturalist. He took his daughter with him tramping through the sweet-smelling woods of Pennsylvania, and the two collected samples of plant life, the leaves, the flowers, and the seeds, to take home and study. Sadly, her father passed away when she was only ten years old, but her scientific curiosity never seems to have left her, and it would come back to the surface in later years, setting her on a path to fame.
Later on when Kwolek was picking a career path, she wanted to be a doctor, so she studied chemistry at what was then the women's college of Carnegie-Mellon University in Pittsburgh. Unable to afford medical school, she decided to get a job in the chemical industry after she graduated, thinking that after a few years of saving her money, she'd go back to school to study medicine.
The story of Kwolek's job hunt has been told many times, and will be told again many times hence. She was invited to a job interview with DuPont, the same company in which Wallace Carothers had worked. She was interviewed by W. Hale Charch, who was an important scientist himself. He was one of the pioneers who made waterproof cellophane a reality. At the end of the interview, Charch told Kwolek that she could expect to find out in about two weeks if she would get the job. Kwolek boldly asked him if she could find out sooner so she could respond to another job offer. Maybe he was impressed by her boldness, because he reacted by calling in his secretary and dictating a job offer letter right on the spot. It just goes to show that a little bit of assertiveness can pay off at times.
She was first assigned to rayon work and then to synthetic fibers. Apparently the curiosity of the young child who collected leaves with her father was still there. She had so much fun doing science that she scrapped the idea of going to medical school. Police officers everywhere are glad she did, as we'll soon learn.
As a synthetic fiber chemist, she built on the work of Carothers, and by changing the structure of nylon, came up with a new family of polymers called aramids. Like nylon, the new aramids were polyamides; that is, their chemical structures contained amide groups.
Anytime one changes the structure of a molecule, one also changes the properties of the material, and the new aramids behaved differently from nylon in many ways. When dissolved, the aramids made liquid crystal solutions. This happens because aramid molecules are long, straight, and rigid. It just so happens that long, straight, and rigid macromolecules are excellent for making incredibly strong fibers. The fibers of one aramid were up to ten times as strong as steel. It was so strong that a fabric woven from the fibers could stop bullets! This material was given the name Kevlar® and you can see its molecular structure below:
This polymer is used to make body armor for police officers. To this day the lives of more than 2000 police officers have been saved thanks to Kevlar® body armor.
In time aramids would save even more lives. Building on Kwolek's work, another aramid was created and given the name Nomex® by DuPont. You can see its molecular structure below.
Can you see how this polymer is different from Kevlar®? Nomex® helped save lives because Nomex®-Kevlar® blends are used to make flame-resistant clothing that protects firefighters, race drivers, and jet pilots.
Kwolek went on to spend a long fruitful career at DuPont before retiring in 1986. She has received many awards and honors for her work, including induction into the National Inventors Hall of Fame. She now spends her time actively promoting science and science education.
- Next: How
Degrading!
For more information, at other Web sites...
- Aramids — a guide to the amazing polymers Kwolek
synthesized, part of The Macrogalleria from the University of
Southern Mississippi.
Kevlar®, The Wonder Fiber — the story of Stephanie Kwolek and aramids, from the Smithsonian Institution.
Stephanie L. Kwolek — a biographical sketch, part of Chemical Achievers, from the Chemical Heritage Foundation.
References
- Kwolek, Stephanie. Interview by Bernadette Bensuade-Vincent, 21 March
1998 at Wilmington, Delaware. Philadelphia: Chemical Heritage Foundation.