Kevlar. The Mysterious Super Fiber

Poly(p-phenylene terephthalamide), or more commonly known as Kevlar®, is the registered name for this special blend of para-aramid synthetic fibers. While working for The Dupont™ Company in the 1960s, a Polish-American chemist named Stephanie Kwolek was tasked with developing a new lightweight fiber designed to replace the bulky steel wires used in car tires at the time cord. You see, back in 1964, the gasoline shortages of the '70s were predicted to create demand for more fuel-efficient cars. By combining a unique polymer formulation, Kwolek discovered the liquid crystals that form in this chemical "soup." At first, the solution wasn't very promising, but she persevered, and after further testing found that when the solution was placed in a "spinneret," it produced fibers that didn't break.

Guess you could say Stephanie is the mother of invention. OK

Kevlar is really just a magic version of plastic. Although, not plastic like a whiffle bat. Due to their unique chemical structure and long-chain molecular arrangement, ultra-tight knitted fibers have properties that allow them to stop bullets when woven into sheets and shoot arrows straight and aimed when woven into strands.

Kevlar is exclusively owned and produced by Dupont, and is related to other fibers such as Nomex and regular nylon, both also developed by Dupont. There are a variety of Kevlar blends to meet specific and unique requirements. Kevlar 29 and Kevlar 49 represent two of the most widely used fibers. Common applications for Kevlar 49 fabrics include: kayaks, canoes, high-speed boats, aircraft panels, sports equipment and wind turbines. Kevlar 49 fabric needs to be a rigid composite part to maximize its physical properties. This eliminates use in dry applications such as clothing or soft body armor. Kevlar 29 fabric is made from tough yarns designed for ballistic protection. Ballistic levels depend on several test factors: weapon type, caliber, bullet type, test range, and projectile velocity.

Kevlar's properties help set it apart from many other fibers and materials. Kevlar is strong but also very light. Kevlar fibers have more than eight times the tensile strength of steel wire. It also handles heat well and can withstand temperatures well above 850ºF. Kevlar will burn, but is easily extinguished by removing the heat source. Kevlar is able to remain soft and pliable down to -320ºF. And even slightly stronger at lower temperatures. Like any superhero, Kevlar has its weaknesses. Prolonged exposure to UV light can cause its fibers to discolor and degrade. Also, certain chemicals on the fiber can weaken it.

Kevlar is often combined with a variety of other materials to produce a range of composite materials. Popular combinations include Kevlar with carbon fiber and Kevlar with stretch materials such as Lycra. The recognizable yellow color of Kevlar is its natural color. It cannot be bleached, but it can be dyed in shades such as red or blue.