The route of modern carbon fiber industrialization is precursor fiber carbonization process. The composition and carbon content of three kinds of raw fibers are shown in the table.

Name of raw fiber for carbon fiber chemical component carbon content /% carbon fiber yield /% viscose fiber (C6H10O5) n4521 ～ 35 polyacrylonitrile fiber (c3h3n) n6840 ～ 55 pitch fiber C, h9580 ～ 90

The process of using these three kinds of raw fibers to produce carbon fibers includes: stabilization treatment (air at 200-400 ℃, or chemical treatment with flame retardant reagent), carbonization (nitrogen at 400-1400 ℃) and graphitization (above 1800 ℃ in argon atmosphere). In order to improve the adhesion between carbon fiber and composite matrix, surface treatment, sizing, drying and other processes are needed.

Another way to make carbon fibers is vapor growth. In the presence of catalyst, discontinuous short carbon fibers with a maximum length of 50 cm can be prepared by the reaction of methane and hydrogen at 1000 ℃. Its structure is different from polyacrylonitrile based or pitch based carbon fiber, easy to graphitize, good mechanical properties, high conductivity, easy to form intercalation compound（ See gas phase growth (carbon fiber).