| 摘要 |
PURPOSE:To prepare mesophase pitch which can easily be spun to filament, made infusible, and carbonized, easily and stably, by heating a raw material pitch at a low temperature to remove the low-molecular components and to narrow the molecular weight distribution, and then heat-treating at a high temperature. CONSTITUTION:The low-molecular component which cannot produce mesophase or produces at a slow rate, is removed from the raw material pitch, by heating the pitch in an inert gas pref. at 350-400 deg.C usually for 5-20hr under stirring. The heat-treated pitch is then heated at a mesophase-producing temperature, i.e. at 400-450 deg.C in an inert gas stream under stirring to obtin mesophase pitch containing 50-70% of mesophase of 50-200mum in diameter. The raw material pitch is most pref. the straight asphalt of petroleum asphalt which is free of the extremely high molecular weight component inhibiting the growth of mesophase. |
