Stephanie Kwolek, Inventor of Kevlar

Marking Time highlights one of the more than 2,500 markers that have been installed throughout the state since 1914 as part of the Pennsylvania Historical Marker Program, operated by PHMC's State Historic Preservation Office.

Born into a Polish American family in New Kensington, Westmoreland County, Stephanie Kwolek (1923–2014) received a bachelor’s degree in 1946 from the Margaret Morrison Carnegie College of Carnegie Mellon University in Pittsburgh. Although she intended to pursue a career in medicine, she took a job with DuPont as a chemist to earn money to attend medical school. She became so involved in her challenging work there that she altered her career plans and remained at DuPont for nearly 40 years.

In the 1950s the field of polymer science was just emerging. Kwolek became involved on the ground level and made several discoveries in her pursuit of new and better polymers. Her most important advance came in 1965 when she experimented with a fiber that she had spun from its liquid form into stiff and durable synthetic strands that were five times stronger than steel. After a decade of follow-up experimentation,  this fiber was released on the commercial market as DuPont Kevlar.

Kevlar is a remarkable material that has been used in the manufacture of many other products. Its best known application, and arguably most significant, is in the fabric used to make bulletproof vests and other protective gear. It is used worldwide by law enforcement and military personnel, and it has saved thousands of lives. Kevlar has been used by the automotive industry for both car bodies and tires. It is used in space vehicles and boats, as well as oven mitts, fiber optic cables, tennis racquets, skis, hiking equipment and camping gear. There are about 200 products that utilize this versatile and beneficial material.

Stephanie Kwolek in the DuPont lab with bobbins of Kevlar, 1980.

Stephanie Kwolek in the DuPont lab with bobbins of Kevlar, 1980.
Courtesy Hagley Museum and Library

Kwolek is also responsible for introducing a common classroom experiment. In the article “The Nylon Rope Trick” in the April 1959 issue of the Journal of Chemical Education, she and coauthor Paul W. Morgan explained how a nylon fiber can be pulled directly from the reaction between two stacked solutions in a beaker. This demonstration of step-growth polymerization is still used in schools today.

By the time Kwolek retired from DuPont in 1986, she held 17 U.S. patents.  In her later years she spent time mentoring aspiring young women scientists and was passionate about introducing children to science.

Kwolek was inducted into the National Inventors Hall of Fame (1995), the Plastics Hall of Fame (1997), and the National Women’s Hall of Fame (2003). She received the American Institute of Chemists’ Chemical Pioneer Award in 1980 and the National Medal of Technology and Innovation in 1996. These are just a few of the many accolades bestowed on this groundbreaking woman scientist.

The Pennsylvania Historical Marker for Stephanie Kwolek was installed and dedicated in her hometown of New Kensington on October 1, 2016.


Karen Galle is on the staff of PHMC’s State Historic Preservation Office and has been the coordinator of the Pennsylvania Historical Marker Program since 2005.