Physical Properties of Pitch-Based Carbon Fibers

4 Physical Properties of Pitch-Based Carbon Fibers 

Carbon fibers based on isotropic pitch have low strength and modulus with tensile strength averaging 870 - 970 MPa and modulus of 40 - 55 GPa (Datafrom Carboflex, Ashland Oil Co., Ashland, KY, and Kureha Chemicals, Japan). 

Mesophase pitch-based carbon fibers generally have the highest stiffness of all carbon fibers with modulus of elasticity up to 965 GPa (140 Msi), considerably higher than PAN-based fibers. The tensile strength however is much lower, averaging only half. As mentioned in the previous section, the compressive-failure strain is low. 

The strength and modulus of pitch-based carbon fibers increase with increasing heat-treatment temperatures as shown in Fig. 8.14. 1 

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