How are carbon fibers and graphite produced?
Carbon fiber is a long, thin strand of material with a diameter of 6-10um or about five times thinner than an average human hair, and composed mostly of carbon atoms. The carbon atoms are bonded together in microscopic crystals that are aligned parallel to the long axis of the fiber. The crystal alignment makes the fiber incredibly strong for its size. Several thousand carbon fibers are twisted together to form a yarn, which may be used by itself or woven into a fabric. Yarn or fabric is combined with epoxy and molded into shape to form various composite materials. Carbon fibers are made from organic polymers such as poly(acrylonitrile). To make carbon fibers, the polymer is stretched into alignment parallel with the axis of the fiber. Then, an oxidation treatment in air between 200- 300oC transforms the polymer into a nonmeltable precursor fiber. This precursor fiber is then heated in a nitrogen environment. As the temperature is raised, volatile products are given off until the carbo
