Whiskerization of carbon beads by vapor phase growth of carbon fibers to obtain sea urchin-type particles

Whiskerization of sulfur-containing hard carbon beads with carbon fibers has been examined to prepare sea urchin-type particles. Propylene was used as a source material for the fiber growth and decomposed at 1000°C for 2 hr. Sulfur-catalyzed carbon fibers 4–6 μm in diameter and 90–120 μm long formed with a density of 400–550 per bead on the surfaces of carbon beads containing ≥ 2.5 wt% sulfur. These beads were prepared by carbonization of styrene/divinylbenzene copolymers sulfonated with fuming sulfuric acid. Very few, if any, fibers grew on beads from copolymers sulfonated with chlorosulfuric acid, probably because of lower sulfur contents (<2.5 wt%) and/or inhibition by residual chlorine.