DuPont

One morning in April 1938, 27-year-old DuPont chemist Roy J. Plunkett cracked open the valve of a pressurized canister containing tetrafluoroethylene (TFE) gas in preparation for an experiment. Much to his irritation, the canister that he had filled the night before appeared to be empty. His assignment had been to find a replacement for the refrigerant Freon 114, on which Frigidaire currently held a monopoly. To conduct his scheduled experiment that morning, he needed to release some TFE into a heated chamber and then spray in hydrochloric acid.

Just after World War II ended, Stephanie Louise Kwolek tucked her new chemistry degree from the Carnegie Institute of Technology under her arm and—because she couldn’t afford medical school—took a research job at DuPont’s textile fibers department in Buffalo. Although she faced many challenges as one of the few women in chemical research, she liked the work so much that she soon dropped her plans to become a doctor. Two decades later she would invent Kevlar, one of the world’s most versatile materials, and along with it a new branch of polymer chemistry.