The bulletproof barrier industry has come a long way since the 1600s, when Prince Rupert’s Drops first emerged in England. While not actually bulletproof, it was discovered that when molten glass is dropped into cold water, it becomes almost indestructible. A few hundred years and a couple accidental discoveries later, bulletproof materials, including bulletproof DuPont™ Kevlar® fiber, are now an integral component to keeping people safe.
Mother of Bulletproof Kevlar Passes Away at 90
It was in the 1960s that the development of bullet resistant fiberglass, also known as bulletproof kevlar, was stumbled upon by Stephanie Kwolek, a research chemist at DuPont laboratories. She had what looked like a bad batch of polymers. Nylon, the world’s first synthetic fiber, was just a few years old at the time, and chemists like Kwolek were eagerly searching for similar fibers for industrial use. In order to do this they produced batch after batch of liquid polymers, which were then forced through the tiny perforations of a spinneret machine, spun into fibers, and tested.
Kwolek’s batch should have been a clear, thick fluid–like nylon polymer–but instead was thin and cloudy. Most researchers would have assumed the batch was tainted, poured it out, and started over. Instead, Kwolek convinced the spinneret operator to send it through anyway. Bullet proof Kevlar was born.
On June 20, 2014, the “Mother of Kevlar” passed away at age 90. U.S. Senator Chris Coons, D-Delaware, said in a statement that “Kwolek had made the world safer.” He called her a legendary scientist and an important part of the history of the small state.
From Tire Belts to Bulletproof Kevlar
By the 1960s America was coming to grips with the early realization that oil was a scarce resource. Since harder tires roll more smoothly, and thus waste less fuel, DuPont tasked a team (including Kwolek) with finding a more rigid material to use in tire belts. Once it was spun into fibers, Kwolek’s inauspicious batch of thin, cloudy polymer didn’t just fit that bill, but far exceeded it. Kwolek had inadvertently discovered a whole new branch of synthetics: liquid crystalline polymers.
Nylon and polyester–the two synthetic polymer fibers made at that time–needed to be heated in order to be spun into fiber. This made their flexible molecules even softer, like cooked spaghetti; the molecules tended to tangle and wind around each other willy-nilly during the process, which made for a highly flexible, but weak, fiber. Kwolek’s thinner liquid crystalline polymer could be spun cool, and its molecules were like stiff little rods instead of spaghetti. As the liquid crystalline polymer is concentrated and forced through the spinnerets, these molecules align, forming long, stiff strands of unbroken molecules. The resulting fiber isn’t just good enough to make terrific tire belts; it’s good enough to stop bullets.
The Advantage of Fiberglass Kevlar Panels
Fiberglass is a hybrid material composed of a flexible cloth matrix soaked in a liquid resin, which is then pressed and baked to make a hard and durable component piece. Since it’s so easy to engineer and integrate into designs, fiberglass is enormously popular in a wide range of fields, from boat design to building construction, military applications to aerospace technology. By using bullet proof Kevlar cloth as the underlying fiber matrix, fiberglass makers can craft panels of fiberglass that can stop bullets. Although this material is more expensive than steel, it introduces significant savings at the installation stage, because it’s so much lighter (just half the weight of steel plate, meaning that walls seldom require reinforcement to accommodate bullet proof Kevlar panels) and easier to work. Contractors can trim, drill, and finish Kevlar panels on the job site using nothing more exotic than a standard hacksaw or power drill.
- Download our Bulletproof Glass Through the Ages Infographic
- Check out our Ultimate Guide to Bulletproof Glass and Bullet Resistant Barriers
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