Polyacrylonitrile (PAN) fiber, pitch fiber or other organic fiber in an inert atmosphere to dissociate elements other than carbon. Most of them from Polyacrylonitrile fiber , Calls Pan fiber ,most 90% carbon fiber is made of PAN fiber, because PAN fiber is better than pitch carbon fiber in terms of the balance of performance, cost,wide usage, etc. Toray manufactures PAN carbon fibers. Toray leads the global carbon fiber industry as the number-one carbon fiber producer in performance, quality and volume.
The two key features of carbon fiber are its excellent strength and light weight. The specific gravity of carbon fiber is around 1.8, which is approx. one-fourth of iron's specific gravity of 7.8. Carbon fiber is also significantly lighter than aluminum and glass fiber having a specific gravity of 2.7 and 2.5, respectively. In addition, carbon fiber has excellent strength and modulus of elasticity: its specific strength calculated by dividing the tensile strength by the specific gravity, is approx. 10 times the specific strength of iron, while its specific modulus of elasticity calculated by dividing the modulus of elongation by the specific gravity, is approx. 7 times that of iron. That's why carbon fiber is a favorite lightweight material to replace conventional metal materials. Carbon fiber has various other characteristics such as not failing due to fatigue, not rusting, and chemically and thermally stable. It is a highly reliable material whose characteristics are stable over long time even under severe conditions.