PREPARATION OF CARBONACEOUS SPHERES FROM SUSPENSIONS OF PITCH MATERIALS

Carbonaceous spheres were prepared from mesophase pitch, isotropic pitch, and fractioned portions of mesophase pitch. The sequential procedure is: suspension in lean suspension medium, removal of dissolving solvent, filteration, and oxidative stabilization. The shapes of spheres obtained depended on the type of solvent, suspension agent, and suspension medium. The carbonaceous spheres prepared from THF soluble fractions (THFS) exhibited relatively narrow distributions of sizes and perfect spheres in shape. The size of spheres could be controlled by the concentration of the soluble fraction of pitch in solution. The spheres prepared from the quinoline-soluble fractions (QS) were reduced in size compared with those from TH FS, and flake-like materials appeared due to the aggregation of spheres upon the removal of quinoline. A specific polymeric suspension agent, polyvinylalcohol (PVA), was stable up to 290-degrees-C, and was employed as a surface active agent in the suspension medium of glycerine.