Thermal and Electrical Properties of Carbon Fibers

Thermal Conductivity. As mentioned above, the fibers with the highest degree of orientation such as the pitch-based fibers have the highest thermal conductivity. As shown in Table 8.10, their conductivity along the axis is higher than even the best metal conductor. PAN-based fibers, on the other hand, have much lower conductivity because of their more pronounced isotropic structure. 

Thermal Expansion. The thermal expansion of carbon fibers, measured along the axis, is extremely low and similar to that of pyrolytic graphite in the ab direction, i.e., slightly negative at room temperature and slowly increasing with increasing temperature (see Ch. 7, Fig. 7.11). The thermal coefficient of expansion (CTE) at room temperature is as follows (data from Amoco Performance Products). 

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