What is the difference between carbon fiber and Kevlar?

What is carbon fiber?

Carbon fibers are long, thin threads made primarily of carbon atoms bound together in microscopic crystals.

The crystals are aligned, which makes them very strong. They are then twisted together, much like the cotton production process, to make yarn. The yarns are then woven together to make carbon fiber cloth. There are different types of weaves for carbon fiber:

Plain Weave: Also known as Two-Way Standard Top/Down is very easy to handle because of the tight weave.

Twill: Diagonal pattern from over-over and under-under It is the best known carbon fiber pattern and offers a looser form than normal designs, making it more suitable for more complex shapes.

Satin: Satin has a brick-like likeness that comes from numbers that are more than (usually four or eight) to less than one. This pattern isn't the easiest to work with, but works best with complex curves.

Unidirectional: As the name suggests, all yarns are unidirectional. There is no weave, usually thread is used to hold it together, but this does not change the structure of the carbon fiber. Best for molds that are stressed in only one axis

How is carbon fiber made?

Each carbon fiber manufacturer has its own method of making the material to give it strength or aesthetic selling characteristics. Typically, however, all carbon fibers come from organic polymers, which are molecular chains of carbon atoms held together.

The PAN (polyacrylonitrile) manufacturing process accounts for about 90% of all carbon fiber manufacturing and is divided into five steps:

Polyacrylonitrile is mixed with other items and spun into fibers, which are then stretched and cleaned.

chemicals are then added to stabilize

Adding heat, high temperatures help form tightly bound carbon crystals.

Fibers are oxidized to improve bonding properties.

Finally, the strands are coated and wound into threads of different sizes. Before carbon fiber becomes a composite, a polymer is added, and the threads and polymer are bonded together by heat, pressure or vacuum to form the composite.

As with any manufacturing process, the materials used will create specific qualities and effects in carbon fiber, allowing for grading and application differences.

What are the benefits of carbon fiber?

Carbon fiber is known for its light weight and high strength, making it an ideal advanced composite material in the marine, automotive and aerospace industries. Key benefits include:

Excellent strength to weight ratio

high heat resistance

High chemical/corrosion resistance (when used with the correct resin)

Extremely flexible for a wide variety of applications

excellent fatigue properties

Suitable for a variety of different materials

electrical and thermal conductivity

Has a low coefficient of thermal expansion

What are the disadvantages of carbon fiber?

Despite its many advantages, carbon fiber is still a relatively new composite material, but it also has some disadvantages:

Expensive compared to other composite materials

Manufacturing is more labor intensive

Currently not recyclable, carbon fiber is often used instead of steel or aluminum, both of which are recyclable materials

Will crack/shatter when exceeded its capacity

If damaged, it must be replaced, not repaired like metal structures