Last month we saw how a bullet-proof jacket works. Did you wonder how the material that it is made of - Kevlar - was discovered? And by whom? Then let's meet Stephanie Kwolek.
Discovery of Kevlar
In 1964, Stephanie Kwolek was looking for a new kind of fibre for making tires. One day in her lab, she had mixed up two chemicals poly-p-Phenylene-terephthalate and polybenzamide (what complicated names!) to see if they would form a polymer. But rather than form a clear solution as a polymer should, this one was fibrous and cloudy. She was about to throw it away, when her technician Charles Smullen suggested that they test the polymer.
It turned out to be stiffer and stronger than nylon. In fact, it was nine times as strong. She sent it to be tested again, but the result was the same. The new polymer turned out to be revolutionary. Called Kevlar, it now has more than 200 applications, from bullet-proof jackets to airplane tires.
Kevlar has been so important in saving lives, police officers often walk up to Stephanie Kwolek to thank her. One of them even asked her to autograph his bullet-proof jacket!
Her life and career
Stephanie Kwolek was born in 1923 in New Kensington, Pennsylvania, USA. She studied chemistry at Carnegie Mellon University, and at first wanted to be a doctor. Not having enough money for medical school, she joined the chemical company DuPont in 1946, where she could earn enough to pay for medical school. It was a great opportunity, for those days such jobs were not available to women.
Just eight years ago, DuPont had invented Nylon, the first synthetic fabric. Stephanie Kwolek was hired to look for similar fibres. She found the work so interesting that she stayed on, and did not go to medical school. She says of herself, "I love doing chemistry, and I love making discoveries."
How did she discover Kevlar? She explains, "I discovered over the years that I seem to see things that other people did not see... if things don't work out I don't just throw them out, I struggle over them, to try and see if there's something there."
Here's a short video biography:
Stephanie Kwolek has 17 patents to her name. She is a fellow of the National Academiy of Sciences of the USA, and has received the Perkin Medal, a medal given to outstanding inventors.