EFFECTS OF CARBON-BLACK ADDITION ON THE CARBONIZATION OF MESOPHASE PITCH

Carbonization of a mesophase pitch produced catalytically from naphtha lene with HF/BF3 was examined by blending carbon black particles to su ppress its severe expansion just before the resolidification that was its major disadvantage for the application as a composite binding subs tance. The carbon blacks were found effective to suppress the expansio n of the mesophase pitch, the particle of large surface area or high o il absorption ability in the pitch such as Ketjen Black (KB) being mos t effective. The KB particles were found well dispersed in the whole a rea of the pitch, extending the chain structure, breaking the molecula r stacking into smaller optical units (fine mozaic), and hindering the graphitization at the calcined and graphitized stages of the mesophas e pitch. Such dispersed particles are expected to release the evolved gases from the molten mesophase pitch along their surface. It is noted that the slurry of the mesophase pitch with carbon blacks maintained the viscosity low enough for smooth impregnation before the carbonizat ion, although the blending certainly increased apparent viscosity.