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Much to her surprise, the fibre was nine times stronger than anything that had come before.

 

A happy accident

In 1964, a team of chemists at DuPont were looking for a strong but lightweight fibre that could be used to strengthen car tyres. At the same time, a chemist named Stephanie Kwolek was investigating aromatic polyimides, a group of long-chain molecules with a rod-like structure. 

She discovered that under the right conditions these molecules would form liquid crystals in solution. The polymer solution was fluid and cloudy, unlike the thick nylon-like solution she was expecting. Convinced this was not simple contamination, Stephanie spun the solution to further investigate. Much to her surprise, the resulting fibre was nine times stronger than any of the fibres previously tested.

 

Stronger than steel

Due to its high number of molecular bonds the fibre (named ‘Fibre B’) proved to be five times stronger than steel, but half as dense as fibreglass – while also being flame resistant. Kwolek shared her discovery with DuPont, who immediately began investing heavily in further research. In 1971, the resultant synthetic material was released as Kevlar.

 

Boots, bridges – and bulletproof vests

Kevlar has been adapted for many purposes, including bulletproof vests. It has saved many lives. In fact, there’s a group of police officers called the DuPont Kevlar Survivors club with 3,100 members. Other uses range from hiking boots and reinforced tyres, to spacecraft and bridges.

Stephanie Kwolek was presented with a number of awards as a result of her discovery, including a National Medal of Technology in 1996. She remained a significant contributor to the scientific community and passionately encouraged more women to pursue careers in science.