Anyone who’s ever seen Christopher Nolan’s The Dark Knight has heard the terms “Kevlar” and “carbon fiber” thrown around. While the two sound perfect together, what makes them such a good pair on a chemical level? Is it really possible to construct your own Batsuit using a carbon fiber design? To see why Lucius Fox (a.k.a. Morgan Freeman’s character) suggested armor platelets over a mesh of carbon fiber, we need to take a closer look at each composite.
Carbon fiber is technically a cloth woven from many thin strands of graphite — and we mean thin: the fibers are between five and 10 microns in diameter, just slightly wider than spider silk. These strands are then laid over a mild and pasted into place using an epoxy resin. The strength of these minuscule fibers comes from their crossed positioning which creates the checkered pattern seen on many carbon fiber prototypes and carbon fiber products.
Kevlar, on the other hand, is constructed on a microscopic level by chaining man-made molecules together into a rigid polymer crystal. As a result, the solution can be spun into strands or poured like a liquid.
Just as both composites are incredibly light, they’re also incredibly strong. However, their strengths when it comes to strength differs: Kevlar is very rigid until it begins to buckle under compression; carbon fiber is generally less resistant to piercing forces (which is why Kevlar is preferred for body armor) but can withstand the high temperatures that weaken Kevlar.
And here we come to the main difference between the two. Kevlar can become severely compromised by the alteration of its shape, hence why Kevlar items are designed to be stiff and rigid. Since body armor plates are produced to stop weapons and projectiles, increased flexibility would result in more impact on the wearer’s body.
On the opposite side of things, the structure of carbon fiber is inherently quite flexible, though the thickness of the sheet does make a difference. In fact, that flexibility is one of the ways it dissipates impact energy, making it more suitable for breakaway items (like car body panels).
The combination of both materials for the ever-iconic Batsuit makes a lot of sense once you consider the nuances of each composite. If you’re planning a project that utilizes carbon fiber design, keep this information tucked away — you never know when it may come in handy!