Anisotropy of electrical conductivity and structure in polymer‐carbon fiber composite materials

Electrical conductivity for polyether and polyimide‐carbon fiber composites was measured using different fiber types. The microstructure was characterized by X‐ray diffraction methods. D.C. conductivity measurements were carried out in directions perpendicular, parallel, and at varying angles to the fiber axis. The influence of the distance between electrodes on the conductivity was examined. The dependence of the frequency and the temperature upon conductivity has been, likewise, investigated. Experimental results support the concept of a conduction mechanism in the composites occurring in the carbon fibers, which built up a highly interconnected conducting network. It is also shown that the high degree of fiber orientation is consistent with the conspicuous anisotropic behavior of the electrical conductivity.