Meso-scale texture of mesophase pitch and its spun fiber Original Research Article

The mesoscopic textures of the mesophase pitch and its spun fiber were examined in the as-prepared and solvent extracted forms using high resolution scanning electron microscopy (HR-SEM). HR-SEM revealed spherical or elliptical grains of 10–50 nm size. Such units were defined as microdomains in the insoluble fraction of the mesophase pitch. The solvent of high dissolving activity reduced the size of the grains, while maintaining their basic shape. No porosity was found in the surface of the microdomain. The as-spun fiber showed a flat textureless plane on its surface along the fiber axis. The solvent extraction closed up the spherical micrograin of 10 nm, as viewed perpendicular to the surface. A tilt angle of 10 ° to the surface of the fiber revealed the pleat alignment of insoluble microdomains.