Name of raw fiber used for manufacturing carbon fiber Chemical composition Carbon content/% Carbon fiber yield/% Viscose fiber (C6H10O5) n4521-35 Polyacrylonitrile fiber (C3H3N) n6840-55 Asphalt fiber C, H9580-90
The process of manufacturing carbon fibers using these three types of raw fibers includes stabilization treatment (in air at 200-400 degree , or chemical treatment with flame resistant reagents), carbonization (in nitrogen at 400-1400 degree ), and graphitization (above 1800 degree in argon atmosphere). In order to improve the adhesion performance between carbon fibers and composite matrix, surface treatment, sizing, drying and other processes are required.
Another method for manufacturing carbon fibers is the gas phase growth method. By reacting a mixture of methane and hydrogen in the presence of a catalyst at a high temperature of 1000 degree , discontinuous short cut carbon fibers can be produced, with a maximum length of up to 50cm. Its structure is different from polyacrylonitrile based or asphalt based carbon fibers, which are prone to graphitization, good mechanical properties, high conductivity, and easy to form interlayer compounds. (See gas phase grown carbon fibers)