Tuesday 4 November 2014

Wardrobe and the Woman 3 : Stephanie Kwolek

Hello lovely bloglets. I know it's been quite a while since we spoke, but I'm hoping you'll all forgive me after reading this week's post! It's another Wardrobe and the Woman, woooooo! (Too keen?) This week’s Woman is Stephanie Kwolek, the brilliant mind behind one of the most important materials of the 20th century: Kevlar.

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Kwolek was born in July 1923 to Polish immigrant parents. Her mother was a seamstress, her father a foundry worker and keen naturalist. Their passions fuelled hers and she would later attribute her interest in science to her father and her interest in fashion to her mother. From a young age Kwolek loved learning new things, making discoveries. She spent much of her early childhood exploring the woods and fields near her home with her father, filling scrapbooks with leaves, grasses, wildflowers, each carefully stuck in and labelled accordingly. She also enjoyed making things, notably clothes for her dolls, and later for herself. Early on she wanted to be a fashion designer. Or a teacher. Or a doctor. In the end she went with doctor, as her mother told her she was too much of a perfectionist ever to go into fashion. (HA!)

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Kwolek’s university years were not an easy time for women in general. Although by the 1940s, it was becoming more normal for women to go to university, Kwolek still remembered being surprised by the enthusiasm and vigour of Dr. Clara Miller, one of her first lecturers and earliest inspirations. Nevertheless, in 1946 she earned her chemistry degree from Margaret Morrison Carnegie College of Carnegie Mellon University (there’s a mouthful for you...) Unfortunately, at this time very few women were being hired into the workplace. Men were beginning to return from the war, and female chemists with PhDs were more likely to work for a year or two before leaving to become teachers.

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Upon graduating, Kwolek decided to work for a while, in order to earn enough money to go to medical school, and so she interviewed at the DuPont Company n Wilmington, Delaware, for a post in textile chemistry. (It turned out that she found the work so exciting that she abandoned her idea for medical school and stayed!) She was interviewed by William Hale Charch (the man responsible for making cellophane waterproof) who told her, at the end of the interview, that he would let her know in a few weeks if she had got the job. In a flash of inspiration, Kwolek told him that she had another offer so he would have to make the decision sooner. Thankfully, her gamble paid off, Charch was impressed and gave her the job on the spot!

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“Poly-paraphenylene terephthalamide” (or “Kevlar” to its friends) is the eldest child in a family of synthetic fibres of exceptional strength and stiffness. Its rather-fetching, stronger-than-steel, yellow, fibrous self was invented by Kwolek in 1965, while her group were searching for a strong but lightweight fibre which could be used in tires, in anticipation of a gasoline shortage. Using a unique technique, Kwolek accidentally produced a cloudy solution which, when spun, produced a fibre which would not break when nylon generally would. (I love how many scientific breakthroughs are mistakes. I’m just waiting for my own to happen now, when I forget to take the bin out or something.) Nylon is usually spun from polymer crystals at over 200⁰c. By working with a condensation of those crystals at room temperature, Kwolek produced a buttermilk-like liquid which, once she’d convinced the technician to spin it, cooled into Kevlar.

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This astonishing material is five times stronger than steel by weight. It is lightweight, flexible, strong, and extremely heat-resistant. In an interview, years later, Kwolek described the moment she realised what she had done: “I knew that I had made a discovery. I didn’t shout ‘Eureka’, but I was very excited, as was the whole laboratory excited, and management was excited because we were looking for something new, something different, and this was it”. The new field of polymer chemistry was born.

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Modern Kevlar was introduced in 1971 and though Kwolek had very little to do with the development of Kevlar’s practical uses (having signed the Kevlar patent over to the company and thereby not profiting from DuPont’s products), her contribution to some of the most common objects in daily life cannot be overstated. As it stands Kevlar is used in more than 200 applications, from tennis racquets and skis, to boats and planes, ropes and tires. From space capsules to suspension bridges, fibre-optic cables to mobile phones, oven gloves to fire-fighting suits.

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Kevlar vest - NOT MY PHOTO

Most importantly, Kevlar was a game-changer for bulletproof clothing. Whereas steel helmets and breastplates might offer some protection, they are no good at dealing with shrapnel. As a fibrous material, there is a great deal of give in Kevlar, so it is not pierced when a bullet hits it. The bullet is slowed down and stopped as the Kevlar bends but does not break. The week Kwolek died, the millionth Kevlar bulletproof vest was sold. In an interview with the Wilmington News Journal in 2007, she said “At least I hope I’m saving lives. There are very few people in their careers that have the opportunity to do something to benefit mankind”.

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Kwolek retired in 1986, but her reputation and achievements remain astounding. Described by DuPont’s chief executive as “a creative and determined chemist and a true pioneer for women in science”, she remains the only female employee ever to be awarded the company’s Lavoisier medal for outstanding technical achievement. Her 1959 paper “The Nylon Rope Trick” won an award from the American Chemical Society and detailed a way of producing nylon in a beaker at room temperature, an experiment which remains a common classroom favourite to this day. In 1980 she received the Chemical Pioneer Award from the American Institute of Chemists, as well as an Award for Creative Invention from the American Chemical Society. She won numerous awards for her work, including the National Medal of Technology, the IRI Achievement Award, and the Perkin Medal. In 1995 she became only the fourth woman ever to be added to the National Inventors Hall of Fame and in 2003 she was added to the National Women’s Hall of Fame.

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Most impressively, Kwolek achieved all of this without ever having done a PhD. She was the only chemist – female or not – at DuPont to have only a BA. (There’s hope for me yet!) Stephanie Kwolek died in June this year at the grand old age of 90, leaving behind an admirable legacy and a material which continues to enrich – and sometimes even save – the lives of many.


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