How do Bulletproof Materials Work?

—Aurora, IL

Graphene has numerous uses in the future, including the creation of new bulletproof materials.

The field of materials science concerns the creation and advancement of new materials, especially solids. Though a somewhat underrepresented field in popular culture in comparison with fields such as computer science, physics, or biology, it has nevertheless contributed greatly to modern society. One of the field’s best discoveries is lightweight bulletproof materials. Kevlar is one of the most popular bulletproof materials often used for military purposes, like body armor, in addition to aerospace engineering. A new up-and-coming material is graphene, which is said to be 200 times stronger than steel while being lighter than paper. The properties of both Kevlar and graphene are extraordinary and allow the materials to protect lots of people across the world.

Kevlar is most often used for military and police vests, though it is sometimes used for other purposes as well.

Kevlar is so ubiquitous in bulletproof materials engineering that it has nearly become synonymous with bulletproof vests. Kevlar is a type of plastic made of a chemical compound known as poly-para-phenylene terephthalamide, created from a chemical reaction between acids and another compound made of nitrogen and hydrogen. The resulting chemical chains of hydrogen, carbon, oxygen, and nitrogen are already extremely tightly bonded. After that, they are “spun”, making the chains parallel and adding hydrogen bonds to cross-link the chains. Kevlar in its final form has a tensile strength ten times stronger than steel, pound for pound. It’s bulletproof because of its tightly bonded fibers, which catch a bullet or other rapid projectile by absorbing and dispersing its energy. The material also doesn’t lose strength in extremely cold environments and doesn’t weaken until 800 degrees Fahrenheit. It is also flexible, making it perfect for clothing applications like gloves or vests. Finally, due to its extremely strong molecular chains, Kevlar has a high cut and puncture resistance. All in all, Kevlar’s extraordinary properties make it perfect for military body armor and vests.

Graphene is a newer material famed for its strength despite its extreme thinness. It is often described as a supermaterial for these magnificent properties: it is 200 times stronger than steel, pound for pound; it is 1000 times lighter than paper; it can conduct electricity better than any other material at room temperature; and finally, it is made of carbon, one of the most plentiful elements in the universe, making production easier. Graphene is made of a layer of carbon atoms arranged in a honeycomb pattern. Each carbon atom is bonded to three other carbon atoms through covalent bonds, leading to the material’s incredible strength. Covalent bonds are formed by sharing valence electrons, of which carbon atoms have 4. The last electron that isn’t shared with other atoms is known as the pi electron. This pi electron is free to move around the material, allowing it to transmit electrical charges extremely easily. Researchers at the City University of New York have recently experimented with multi-layer graphene by shooting high-speed microscopic projectiles at it. Before the projectiles broke through, the graphene dispersed the energy so well that it had the hardness of diamond for a split second. Scientists believe that thicker versions of graphene can completely stop bullets while still being thinner than regular bulletproof materials like Kevlar.

Future graphene advancements may make it completely resistant to projectiles such as bullets.

Overall, materials science and engineering has proven to be extremely useful for a variety of applications, the military in particular. Both Kevlar and graphene are incredible feats of engineering that have advanced society substantially. If these materials can be created in the present, who knows what the materials scientists of tomorrow will cook up?