What Are the Features and Capabilities of Carbon Fiber Structure?

Of all the construction and manufacturing materials available to professionals and the general public today, carbon fiber is one of the most distinctive, interesting, and useful. With an appearance that looks like woven strands of metal, carbon fiber’s structure offers a host of advantages and potential applications.

Below is your guide to all things carbon fiber. What is carbon fiber? What makes the carbon fiber structure unique and so useful? And why do material scientists and engineers continue exploring and expanding the possibilities for this material?

What Is Carbon Fiber?

Carbon fiber — also called graphite fiber — is a lightweight but extremely strong polymer.

A polymer is a substance — either synthetic or natural — comprised of large molecules. These molecules are called macromolecules, and are in turn made up of chemicals called monomers. Here are some examples of materials comprised primarily of common polymers:

• Protein
• Nucleic acids (found in DNA)
• Cellulose
• Diamonds, quartz, and other minerals
• Plastics and rubbers
• Concrete and glass

As you can see, polymers exist of their own accord in nature, but they can also be created and manipulated into new configurations and forms that are useful to us.

The carbon fiber structure is not a naturally occurring polymer. However, in the name of sustainability, scientists are actively researching how to create it using as natural a process as possible. Currently, the precursor required to form the carbon fiber structure is called poly-acrylic-nitrile (PAN). PAN is is an entirely synthetic resin.

In the near future, it could be possible to mass-produce carbon fiber structures using a naturally occurring compound called lignin. Lignin is the polymer that makes up the structure of  the cell walls of plants. It’s rigid enough to take the place of PAN as a precursor in carbon fiber fabrication.

As material scientists work to make the fabrication process of carbon fiber friendlier to the earth and less energy-intensive, it’s worth exploring why carbon fiber is so desirable in the first place. What is it about the structure of this polymer that makes it so widely applicable to human manufacturing, building, and other activities?

Why Is the Carbon Fiber Structure so Useful?

What are the advantages of carbon fiber? What is it about this polymer’s structure that makes it so desirable for such abundant applications? Here are a few facts about carbon fiber that should shed some light on the subject:

• Carbon fiber could replace steel and titanium. Some carbon fiber composites are up to 60 times stronger than steel and 15 times stronger than titanium relative to its weight. The positive implications for construction and manufacturing are considerable.
• Transportation could become less wasteful. It’s expected that new formulations of carbon fiber could reduce the weight of passenger cars by 50% and boost their fuel efficiency by 35%. This is a timely breakthrough given the urgency of the climate crisis.
• Renewable energy systems benefit from carbon fiber. Environmentally minded material scientists have targeted carbon fiber as the means to improve the performance, efficiency, and longevity of wind-power turbine installations.
• It’s possible to 3D print using carbon fiber. 3D printing represents a major sea change in how common materials are fabricated. Now, it’s possible to marry the waste- and cost-saving benefits of 3D printers with the strength and low weight of carbon fiber. Some 3D printers have reached the size of shipping containers to facilitate the creation of large components and structures, like cars and bridges.

This is actually just the beginning of a full accounting of carbon fiber’s advantages and possibilities. It’s also impervious to corrosion even when fully submerged in water.  Additionally, it’s extremely resilient against temperature extremes, it allows x-rays to pass through it, and it resists damage from a host of harsh chemicals that exist in manufacturing environments.

How Is Carbon Fiber Material Created?

The carbon fiber structure itself is a long filament made of carbon atoms. These atoms are combined with plastic-based polymers (resins) using extreme heat in a vacuum. The vacuum creates a lack of oxygen, which means the filaments can be superheated without burning them up.

The result is a slender chain of atoms that, when bonded in this fashion, provide strength that’s totally disproportionate to the material’s low weight. The strength of the resulting material is determined by two additional variables:

• The angle used to weave the filaments together.
• The type of resin bonded with the carbon atoms.

The most common resins employed in carbon fiber fabrication at this point in time include vinyl ester, polyurethane, thermoplastic, and polyester.

It is, primarily, the spectacular strength-to-weight ratio that makes carbon fiber materials a desirable — if not yet a practical — alternative to steel, titanium, other metals, and many kinds of plastic. Here are just a few of the manifold applications for various carbon fiber and thermoplastic blends:

• Lightweight components for race cars and passenger automobiles
• High-performance aeronautical and aerospace parts
• Strong, lightweight frames for bicycles
• Puncture-resistant soles for footwear
• Fishing rods
• Baseball bats, hockey sticks, and other sporting equipment
• Protective elements for satellites and spacecraft
• Durable junctions and connectors for oil, gas, and utility companies
• Parts for drones, probes, and other unmanned vehicles
• Furniture, decorations, and other consumer goods
• Structural beams for homes, apartments, bridges, and high-rise skyscrapers
• Implants, prostheses, and other medical devices

We mentioned practicality above, and that remains the only limiting factor when it comes to deploying this apparently miraculous material on a more wide-scale basis.

Carbon Fiber Has Limits but Incredible Untapped Potential

Carbon — along with alloys containing carbon — is one of the most plentiful elements on planet Earth. So why does it seem like carbon fiber is so hard to come by, despite its incredible capabilities? Why aren’t carbon fiber structures everywhere?

The major limit to carbon fiber’s practicality is its cost. The multi-step process required to fabricate this material requires considerable know-how, specific materials, and specialized equipment. The cost of the required machines is the biggest barrier to entry for most companies looking to use carbon fiber.

In addition to lignin, even polyester — a cheap and common material — can serve as a precursor to create carbon fiber. Unfortunately, like diamonds, the substrate material being inexpensive is only one factor accounting for the price of the finished product; there’s also the highly specialized machinery and training that conspire to keep carbon fiber pricy.

3D printers were cost-prohibitive a few years ago, but now any hobbyist can own one. Engineers will, soon enough, figure out how to bring down the cost of carbon fiber fabrication equipment. When that day comes, we’ll begin seeing even more impressive and consequential contributions to the built environment from this deceptively simple material.