MECHANISM OF FORMATION OF THE TEXTURE AND MICROTEXTURE IN AS-SPUN THEN OXIDIZED ANISOTROPIC PITCH-BASED CARBON-FIBERS .2. RADIAL TYPE-I2

The microtexture of a radial type of fiber I2 is that of an edge-to-edge type of gel elongated uniaxially by spinning. The structure finally obtained follows a model derived from that of the radial-with-wedge type of fiber I1, inside which an increasing disorder is introduced. It is still a combination of two orthogonal orientations of the aromatic layers in the core of the fiber, disrupted near the surface. In the core, a dominant radial texture 2 (containing radial aromatic layers) turns to spiral at the periphery; 2 is constantly prolonged parallel to the fiber axis. The maximum disordering is introduced in the channels 3. They still have a concentric orientation of their aromatic layers and are still dotted along the fiber axis. However, they are strongly distorted in either cross- or longitudinal sections and the dots are not well aligned along the fiber axis. The isotropic phase of the initial pitch is elongated as fibrils. There is no central isotropic pole.