Stephanie Kwolek

By Mark Steer

Stephanie Kwolek
(1923 - )

Stephanie Kwolek started working at DuPont, the company which had first produced nylon, with the express intention of leaving after a couple of years to study medicine. Luckily she found her work so interesting that she decided to ditch her plans and stay on in the chemical labs.

She arrived at DuPont in 1946 and was quick to excel. When the company opened its Pioneering Research Laboratory in 1950, she was quick to transfer to Delaware so as to be part of the proceedings. It was here that she had a string (if you’ll pardon the pun) of successes researching polymers – long chain-like molecules created by linking lots of smaller molecules together.

Her research centred on trying to find ways to manufacture polymers at low temperatures. At the time, the only process by which nylon could be produced required temperatures of 200^oC and above. This meant that other polymers which were unstable at high temperatures, or wouldn’t melt, simply couldn’t be manufactured.

The fruits of her work started to come to bear in the late 1950s when she published a paper detailing how nylon could be manufactured at room temperature. It’s a process – the nylon rope trick as she called it – which is now regularly repeated in school chemistry lessons the world over.

Kwolek’s biggest breakthrough came during the 1960s when she was the first to produce a whole new family of chemicals called aramids. In 1964, one of these chemicals in particular caught her notice. In solution it didn’t act like other polymers; instead of being a thick, clear liquid this was a murky, runny substance. Had another chemist created this strange mixture they might well have simply chucked the stuff away assuming it was useless and, indeed, the man who was in charge of trying to spin new fibres out of the solutions initially refused to try Kwolek’s new chemical for fear that it would gunge up his machine. Fortunately, he was finally persuaded and to everyone’s surprise he easily spun out a long fibre stiffer and stronger than any that had previously been produced. It was the precursor of Kevlar - the material of bulletproof vests.

The extreme strength and rigidity of the fibres found immediate favour and in 1971 the material was marketed for the first time. Kevlar is now not used just in protective clothing, but also in boats, airplanes, ropes, cables, tires, tennis racquets, skis, and around 200 other products.

Since retiring in 1986, Kwolek has continued to work as a consultant chemist and mentor, particularly for other women scientists.

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