How does Kevlar work?
That’s actually a very interesting question. Kevlar is actually a super-strong plastic invented at the DuPont Chemical Company by a woman named Stephanie Kwolek. Revealing that Kevlar is a plastic that may not sound all that impressive, but not all plastics are created equal. The molecular bonds inside Kevlar are amazingly strong because of the way the molecules are arranged. Kevlar actually starts out as a thin, watery liquid, but when it hardens it forms incredibly tight chemical bonds. It takes a lot of energy to make a Kevlar thread stretch. Another similar thread is called Dyneema, which is a polyethylene-based plastic made through a slightly different process.
Using The Thread To Make The Kevlar Yarn
Those tough Kevlar threads are then spun into a yarn that looks like cord or string. That cord is so strong that it finds uses in many industries, including the manufacture of fabrics used in bulletproof panels. Kevlar cord is not only tough, it’s also heat resistant which explains why it finds applications in brake pads and spacecraft. Kevlar is very similar to another product that firefighters and race car drivers are familiar with called Nomex, which is used in fire protective clothing. To make the fabrics used in bulletproof panels that Kevlar yarn is woven into a fabric sheet. It’s the strength of those woven sheets that really answer the question, how does Kevlar work?
Making a Ballistic Panel
Several sheets of the woven Kevlar fabric are then stitched together to make the bulletproof panels inside a ballistic vest. The proper amount of the fabric layers is determined by testing against various types of handgun and rifle ammunition and matched against known threat protection standards. Those threat protection standards have names like Level IIA, Level II, Level IIIA, Level III and Level IV. Each threat protection level is matched against a particular type of threat like handguns, rifles and even armor piercing ammunition. At the highest threat protection levels the Kevlar soft armor panels might be supplemented by ceramic hard armor plates.
No Path For a Bullet
There are so many interwoven strands of that tough Kevlar thread that when a bullet strikes a Kevlar panel it can’t find a way through that tough screen and gives up all its energy just stretching the Kevlar fabric a small amount. A few threads may break but not enough to create a path for the bullet. The energy of the bullet is then dissipated outward instead of punching through the fabric.
We hope that this answers the question
How does Kevlar work?