What Is Carbon Fiber?
Carbon Fiber is a synthetic material in which the carbon atoms are bonded with a really small crystal which requires a michroscope to see. Obviosusly carbon fibers consist mostly of carbon atoms. Keyword "Carbon." Zoltek states, "A carbon fiber is a long, thin strand of material about 0.0002-0.0004 in (0.005-0.010 mm) diameter and composed mostly of carbon atoms." The allignment of the crystals that are bonded with the carbon atoms insure incredible strength for the size of the carbon fiber strands. According to Innovative Composite Carbon fiber is five-times stronger than steel and twice as stiff. Though carbon fiber is stronger and stiffer than steel, it is lighter than steel; making it the ideal manufacturing material for many parts.
How it is made
The precursor which is used to make carbon fiber is called, polyacrylonotrile (PAN). A precursor is a substance from which another is formed, especially by metabolic reaction. According to Merriam Webster, polyacrylonotrile is, "a polymer of acrylonitrile used often as fibers." Polyacrylonotrile is the main ingredient/ material in carbon fiber. In fact, Zoltek proclaims, "About 90% of the carbon fibers produced are made from polyacrylonitrile (PAN)." The rest of carbon fiber is made from rayon or petroleum pitch. Rayon is any group of smooth textile fibers made from regenerated cellulose by extrusion through minute holes. Pubs.ASC explains that petroleum pitch is a, "thick, dark colored bituminous substances obtained as a result of industrial destructive distillation processes, obtained as deposits on the earth surface, or, of primary interest here, manufactured from a specially selected feedstock." Varieties of gas and liquid are also used in the creation of carbon fiber. The materials used can be designed to react with fiber for a special effect. First, fibers are made with the precursor and then they are heated at an extreme temperature. When people are on the part of heating during manufacturing they make sure the fibers do not come in contact with oxygen. This is to prevent the fibers from catching on fire. After heating the fibers at an extreme temperature most of the non-carbon atoms are gone leaving only a few left. Zoltek states, "This process is called carbonization and leaves a fiber composed of long, tightly inter-locked chains of carbon atoms with only a few non-carbon atoms remaining." When manufacturing carbon fibers from polyacrylonotrile, there is a sequence of steps normally used. These steps are spinning, carbonizing, treating the surface, and sizing. During spinning a plastic powder and other plastics are mixed together. The plastic powder is called Acryilonitrile. The other plastics could be stuff like "methyl acrylate or methyl methacrylate." After doing some stuff to the plastics, they are spun into fibers. There are many methods to do this. They are "washed and stretched." Now to talk about stabilizing. This process occurs before carbonization because they need to be chemically changed. This creates a more "thermally stable ladder bonding." The fibers are heated around 200-300 degrees celsius. The heating occurs in contact with oxgen. During carbonization the fibers are heated at extreme temperatures of 1,000-3,000 degrees celius. However this occurs without the fibers coming in contact with oxygen. As explained in less detail at the beginning, this process gets rid of most of the non-carbon fibers. Treating the surface is the next step after carbonization. Zoltek states, "After carbonizing, the fibers have a surface that does not bond well with the epoxies and other materials used in composite materials." Treating the surface gives the fibers better properties for bonding. The last step of manufacturing carbon fiber is classified as sizing. Sizing doesn't really mean what the name says. However, this process is when the fibers are coated. This gives them better protection. Zoltek says, "Coating materials are chosen to be compatible with the adhesive used to form composite materials. Typical coating materials include epoxy, polyester, nylon, urethane, and others." Then you weave the coated fibers into cylinders. These cylinders are called bobbins. After this they are twisted into different sized yarns. *Click any of the links to Zoltek and scroll to the bottom to see the process in more detail.*
Facts About carbon Fiber
- Another name for carbon fiber is graphite fiber. It is a strong, stiff, lightweight material that has the potential to replace steel and is popularly used in specialized, high-performance products like air crafts, race cars and sporting equipment.
- Carbon Fiber was first invented in Clevland, Ohio.
- The methods that we use to make carbon fiber today are slow.
- Carbon fiber can be woven into fabric that can be used for defense purposes. They can also be used for vehicle parts or wind turbine blades.
- It was created in 1850
- It was also used for the filaments of lamps in 1880-1907