Stephanie Kwolek began working at DuPont with a team of chemists called the Pioneering Research Laboratory, exploring new polymer fibers and new ways to make them.
In 1964, her group decided to search for a new high-performance fiber. They had a specific use in mind for it: there were predictions of a gasoline shortage, and they thought that a strong, lightweight fiber could be used to reinforce car tires. Lighter, stiffer tires would use less gasoline. "A number of people had been asked to take up this project and no one seemed to be particularly interested," Kwolek explains. "So I was asked if I would do it."
"In the course of that work I made a discovery," she says modestly. Under specific conditions, the polymers she was working with would form liquid crystals in a solution, which no polymer had ever done before. And instead of the usual "bent" polymer molecules—she likens them to spaghetti—these were straight, like match sticks. When the cloudy solution was "spun"—forced through the tiny holes of a device called a spinneret—the straight fibers lined up parallel to each other. This made the new fiber very stiff and very strong.
It was not easy for Kwolek to get the polymer solution into the spinneret. "That solution was very different from the standard polymer solution," she recalls. "It had a lot of strange features. I think someone who wasn't thinking very much or just wasn't aware or took less interest in it, would have thrown it out." Kwolek filtered it to see if the cloudy solution was contaminated. It wasn't. Still, she continues, "when I submitted it for spinning the guy refused to spin it. He said it would plug up the holes of his spinneret, because he assumed that [it had] solid particles. So it was a while before he consented to spinning it. I think either I wore him down or else he felt sorry for me."
When a chemist spins a fiber, she sends it to a lab to test its strength, stiffness, and other properties. This new fiber came back from the lab with a stiffness at least nine times greater than anything she'd made before. DuPont realized it had a fiber with great potential. After much more work and refinement by the group, Kevlar was introduced in 1971. The fiber has since found more than 200 applications.
Le moment de zadigacité
1965. Découvert accidentellement par Stephanie Kwolek, 43 ans, chercheuse chez DuPont alors qu'elle faisait des recherches pour trouver des fibres supérieures à l'acier et au nylon pour les pneus d'automobiles.
Elle ne jette pas la solution étrange obtenue comme cela se fait d'habitude. Son supérieur comprend la signification de cette découverte.