Polyacrylonitrile carbon fiber manufacturing from

Low density, carbon fiber-carbon binder composites are fabricated from a variety of carbon fibers, including fibers derived from rayon, polyacrylonitrile (PAN), isotropic pitch, and mesophase pitch. The manufacture, structure, and properties of carbon fibers have been thoroughly reviewed elsewhere [3] and. therefore, are... 

Whereas carbon fibers with a low carbon content are formed predominantly from aliphatic raw materials (rayon), carbon fibers with a high carbon content are produced from aromatic feedstocks or easy-to-aromatize base materials. The most important raw materials for the manufacture of high-carbon fibers are polyacrylonitrile and mesophase pitch. 

Carbon fibers are made from many different feedstocks. The most important commercial fiber is made from polyacrylonitrile (PAN). It is four times stronger than steel, the same modulus or higher, and does not fail in creep or fatigue. These properties made the fiber attractive for aerospace applications initially, and later for sporting and industrial applications. Another important feedstock is pitch from refinery or steel-making operations, which leads to fibers with very high modulus and thermal and electrical conductivities. Properties of the fibers, and critical steps in their manufacture are described, together with structural characteristics and failure mechanisms. 

Carbon fibers are manufactured by pyrolysis and thermal treatment of organic precursor fibers, viz., rayon, polyacrylonitrile (PAN), or pitch. In pilot plant quantities, carbon fibers have been grown by chemical vapor deposition from an organic vapor such as methane or benzene in the laboratory, they have also been grown by physical vapor deposition. 

Manufacturing techniques for producing carbon fibers are relatively complex and are not discussed. However, three different organic precursor materials are used rayon, polyacrylonitrile (PAN), and pitch. Processing techniques vary from precursor to precursor, as do the resultant fiber characteristics. 

Various surface pretreatments, often referred to as primers, are put on fibers and other textiles by the manufacturers to enhance subsequent bonding. Depending on the subsequent use of the textiles, the change in adhesion can be negative, nonexistent, or positive. In interlaminar shear strength tests of untreated and oxidative surface-treated polyacrylonitrile-based carbon fiber/epoxy composites the shear stress went from 14.9 to 22.1 MPa. 

The facile formation of ceramic materials from molecules has undoubtedly been one of the si ificant contributions made by chemistry to materials science (7). However, it is desirable not only to produce the ceramic per se but also to do so in a specific form, for example a fiber. Therefore, one of the key requirements for any ceramic precursor should be its processability. For this reason, there has been continued research effort aimed at the design of precursors with physical properties suitable for processing prior to pyrolysis. Two examples with sigr cant commercial application are polyacrylonitrile and polyorganosilanes, both of which may be spun into fibers, and upon pyrolysis allow for the manufacture of carbon-graphite (2) and silicon carbide (5) fibers, respectively. Despite much effort, the extension of this polymer-type precursor strategy to other ceramic systems has only met with limited success. 

---