Stephanie Louise Kwolek was an American chemist, whose career at the DuPont
company spanned over forty years. She is best known for inventing the first of a
family of synthetic fibers of exceptional strength and stiffness:
poly-paraphenylene terephthalamide—better known as Kevlar.
For her discovery, Kwolek was awarded the DuPont company's Lavoisier Medal for
outstanding technical achievement. As of February 2015, she was the only female
employee to have received that honor. In 1995 she became the fourth woman to be
added to the National Inventors Hall of Fame. Kwolek won numerous awards for her
work in polymer chemistry, including the National Medal of Technology, the IRI
Achievement Award and the Perkin Medal. Early life and education
Kwolek was born to Polish immigrant parents in the Pittsburgh suburb of New
Kensington, Pennsylvania, in 1923. Her father, John Kwolek, died when she was
ten years old. He was a naturalist by avocation, and Kwolek spent hours with
him, as a child, exploring the natural world. She attributed her interest in
science to him and an interest in fashion to her mother, Nellie Kwolek.
In 1946, Kwolek earned a Bachelor of Science degree with a major in chemistry
from Margaret Morrison Carnegie College of Carnegie Mellon University. She had
planned to become a doctor and hoped she could earn enough money from a temporary
job in a chemistry-related field to attend medical school.
DuPont career In 1946, Hale Charch, a future mentor to
Kwolek, offered her a position at DuPont's Buffalo, New York, facility.
Charch had initially told Kwolek that he would contact her within two weeks, but
after Kwolek said she had to answer another job offer and insisted on a
faster reply, Charch immediately offered her the position.
Although Kwolek initially only intended to work for DuPont temporarily, she
found the work interesting and decided to stay rather than pursuing a medical
career. She moved to Wilmington, Delaware, in 1950 to continue to work
for DuPont. In 1959, she won the first of many awards, a publication award from
the American Chemical Society. The paper, The Nylon Rope Trick,
demonstrated a way of producing nylon in a beaker at room temperature. It is
still the basis of a common classroom experiment.
= Kevlar= While working for DuPont, Kwolek
invented Kevlar. In 1964, in anticipation of a gasoline shortage, her
group began searching for a lightweight yet strong fiber to be used in tires.
The polymers she had been working with at the time, poly-p-phenylene
terephthalate and polybenzamide, formed liquid crystal while in solution that at
the time had to be melt-spun at over 200 °C, which produced weaker and less-stiff
fibers. A unique technique in her new projects and the melt condensation
polymerization process was to reduce those temperatures to between 0–40 °C.
As she later explained in a 1993 speech: “The solution was unusually, turbid,
stir-opalescent and buttermilk in appearance. Conventional polymer
solutions are usually clear or translucent and have the viscosity of
molasses, more or less. The solution that I prepared looked like a dispersion
but was totally filterable through a fine pore filter. This was a liquid
crystalline solution, but I did not know it at the time.”
This sort of cloudy solution usually was thrown away. However, Kwolek persuaded
technician Charles Smullen, who ran the spinneret, to test her solution. She was
amazed to find that the new fiber would not break when nylon typically would.
Not only was it stronger than nylon, Kevlar was five times stronger than
steel by weight. Both her supervisor and the laboratory director understood the
significance of her discovery, and a new field of polymer chemistry quickly
arose. By 1971, modern Kevlar was introduced. Kwolek learned that the
fibers could be made even stronger by heat-treating them. The polymer
molecules, shaped like rods or matchsticks, are highly oriented, which
gives Kevlar its extraordinary strength. = Applications of Kevlar=
Kwolek was not very involved in developing practical applications of
Kevlar. Once senior DuPont managers were informed of the discovery, they
immediately assigned a whole group to work on different aspects," she said.
She also did not profit from DuPont's products, as she signed over the Kevlar
patent to the company. Kevlar is used as a material in more
than 200 applications, including tennis rackets, skis, boats, airplanes, ropes,
cables, tires, and bullet-proof vests. During the week of Kwolek's death, the
one millionth bullet-resistant vest made with Kevlar was sold. Kevlar is also
used to build cellular telephones; Motorola's Droid RAZR has a Kevlar
unibody. Awards and honors
For her discovery of Kevlar, Kwolek was awarded the DuPont company's Lavoisier
Medal for outstanding technical achievement in 1995, as a "Persistent
experimentalist and role model whose discovery of liquid crystalline
polyamides led to Kevlar aramid fibers." At the time of her death in 2014, she
was still the only female employee to receive that honor.
In 1980, Kwolek received the Chemical Pioneer Award from the American
Institute of Chemists, and an Award for Creative Invention from the American
Chemical Society. In 1995, Kwolek became the fourth woman to be added to the
National Inventors Hall of Fame. In 1996, she received the National Medal of
Technology and the IRI Achievement Award. In 1997, she received the Perkin
Medal from the American Chemical Society. In 2003, she was added to the
National Women's Hall of Fame. She has been awarded honorary degrees by
Carnegie Mellon University, Worcester Polytechnic Institute and Clarkson
University. The Royal Society of Chemistry grants a
biennial 'Stephanie L Kwolek Award', "to recognise exceptional contributions to
the area of materials chemistry from a scientist working outside the UK".
Kwolek is featured as one of the Royal Society of Chemistry 175 Faces of
Chemistry. Retirement
In 1986, Kwolek retired as a research associate for DuPont. Toward the end of
her life, she consulted for DuPont, and served on both the National Research
Council and the National Academy of Sciences. During her 40 years as a
research scientist, she filed and received either 17 or 28 patents.
Kwolek died at the age of 90 on June 18, 2014.
References Further reading
Edwin Brit Wyckoff, Stopping Bullets with a Thread; Stephanie Kwolek and Her
Incredible Invention, Enslow Elementary, ISBN 9780766028500, OCLC 74029319,
076602850X External links
Media related to Stephanie Kwolek at Wikimedia Commons
Stephanie Kwolek at Famous Women Inventors
Interview with Stephanie L. Kwolek, March 21, 1998, from the Center for Oral
History at the Chemical Heritage Foundation
Stephanie Kwolek, Video, from The Catalyst Series: Women in Chemistry, at
the Chemical Heritage Foundation, Philadelphia, PA