The raw material used to make carbon fiber is called the precursor. About 90% of the carbon fibers produced are made from polyacrylonitrile. The remaining 10% are made from rayon or pertoleum pitch. All of these materials are organic polymers, characterized by long strings of molecules bound together by crbon atoms,The exact composition of each precursor varies from one company to another and is geneerally considered a trade secret.

During the manufacturing process, a variety of gases and liquids are used. Some of these materials are designed to react with the fiber to achieve a specific effect. Other materials are designed not to react or prevent ceactions with the fiber. As with the precursors, the exact compositions of many of these process materials are considered trade sectets.

The process for making carbon fibers is part chemical and part mechanical. The precursor is draw int long strands or fibers and then heated to a very high temperature with-out allowing it to come  in contact wiht  oxygen. Without oxygen, the fiber cannot burn. Instead, the high temperature causes the atoms in the fiber to vibrate violently until most of the non-carbon atoms are expelled. This process is called carbonization and leaves a fiber composed of long, tightly inter-lockied chains of carbon atoms wiht only a few non-carbon  atoms remaining.