A Brief History of BulletproofS

Kevlar. The world is lousy with this stuff: from body armor to tires to shoelaces; from to suspension bridges to the Ove Glove. But when Kevlar was invented 45 years ago, it didn't look like something that could save a life. It looked like a mistake.

In the years leading up to World War II, the product development types at DuPont had their sights on some potentially lucrative objects in need of extreme material makeovers—juicy government contracts like the soldier's steel helmet. They wanted to replace the heavy and uncomfortable headgear with something light but just as protective. DuPont also thought the mythical material could have uses in the automotive industry. Steel belted radials could be replaced by something with more bend and greater strength. Basically, they were looking for a man-made spider silk that could steal steel's business. So they set their geniuses to work.

DuPont researcher Stephanie Kwolek discovered the super fiber in 1965 while playing around with polymers. She discovered these really strong chains of molecules called liquid crystalline polymers. Problem was, they were moody, and broke down really easily. Kwolek knew she was on to something, but she needed a better way to process the stuff to make it less sensitive.

She designed a solvent to make the long chains of molecules more stable, but the solution kept coming up cloudy. The best scientific knowledge of the time said that cloudy solutions were trash, but when batch after batch kept coming up mirky, Kwolek figured she'd ignore the conventional wisdom and see if she could coax a fiber out of the stuff. She could. That cloudiness turned out to be a signal of strength. She had discovered a material lighter than steel, but five times as strong.

A Brief History of Bulletproof

Fast-forward to 1971. An army officer named Nick Montanarelli heard about a super strong fiber the Army was testing in tires—Kevlar. He called Lester Shubin, the director of the National Institute of Justice (NIJ), and suggested that this new material might have a future in body protection. To test the theory, the two men wrapped a phone book in Kevlar and started firing at it. The bullets ricocheted off.

Phone books were one thing, but the NIJ needed to know if the impact caused internal trauma to the body, even if there was no broken skin. Unfortunately, cadavers and dummies, usually ideal test subjects, didn't have expressive enough insides. Goats, though, could indicate to army surgeons how a human might fare. And they did. The 5-ply Kevlar vest didn't protect the sacrificial goats from a .22 long riffle shot at a 30-degree angle. But after tightening the weave and adding two extra layers, the goats made it through trials with .22s, .38s, .357s and 30-ought-6s (they didn't, though, make it through the exploratory surgery afterwards). By 1978, the US Army tapped DuPont to produce Kevlar for their flak jackets and helmets.

Today, Kevlar cables hoist elevators and help land rovers on Mars. Body armor made with the stuff keeps our soldiers safe. And to protect our sweet fingers from 350 degree pot pies, there's the Ove Glove's Kevlar-striped palm. It only took four decades of research and the lives of several dozen unfortunate goats.