Carbon_fiber_reinforced_composite2英文电子资料.pdfVIP

CHAPTER 2 Processing of Carbon Fibers Introduction Carbon fibers are fabricated from pitch fibers, polymer fibers (e.g., polyacrylonitrile), or carbonaceous gases (e.g., acetylene). Those made from pitch and polymer fibers are commercially available, whereas those made from carbonaceous gases are not yet commercially available. Those made from pitch and polymer fibers are in short and continuous forms, whereas those made from carbonaceous gases are in the short form only. Fibers made from pitch and carbonaceous gases are more graphitizable than those made from polymers, so they can attain higher thermal conductivity and lower electrical resistivity. The raw materials cost is much lower for making fibers from pitch or carbonaceous gases than from polymers. However, the present market is dominated by those made from polymers because of their combination of good mechanical properties (particularly tensile strength) and reasonable cost. In contrast, highly graphitic pitch-based carbon fibers are very expensive, though they have high tensile modulus, high thermal conductivity, and low electrical resistivity. On the other hand, the price of pitch-based carbon fibers is expected to drop when the production volume increases. Eventually, the least expensive carbon fibers are expected to be those made from pitch and carbonaceous gases. The fabrication of carbon fibers from pitch or polymers involves pyrolysis of the pitch or polymer; this is performed by heating. Pyrolysis is akin to charring, thus forming carbon. In contrast, the fabrication of carbon fibers from carbonaceous gases involves catalytic growth of carbon. For the pyrolysis process, pitch has the advantage of having a higher carbon yield than polymers. This chapter describes the me