PAN as Precursor

Polyacrylonitrile (PAN) is the most favored precursor at this time for the production of high-performance fibers. PAN-based fibers are in the medium price range (- 40/ kg in 1992). They have the highest tensile strength of all carbon fibers and a wide range of moduli and are readily available in a variety of tows. 

Precursor Requirements. To produce the optimum carbon fiber, a precursor fiber should perform the following functions Pi 

PAN essentially meets the requirements. It was originally developed as an organic synthetic textile fiber and this is still by far its major use. It has also shown to be an ideal precursor for the production of carbon fibers, but only when produced by the wet-spinning process (as opposed to the more common and cheaper dry-spinning). 

PAN is usually co-polymerized with a small amount of another monomer such as methyl acrylate or vinyl acetate. This co-polymerization lowers the glass-transition temperature from 120°C to 100°C and, as a result, improves the spinning and stretching characteristics. 

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