软沥青热聚合制备高含量中间相预聚体的研究

STUDY ON THE THERMAL POLYMERIZATION PREPARATION OF PRE-POLYMER WITH HIGH-CONTENT MESOPHASE FROM COAL TAR PITCH

以煤系软沥青为原料,采用多管井式坩埚炉进行沥青热聚合反应.通过跟踪反应过程样品族组成及显微结构变化,探究软沥青热转化制备高含量中间相预聚体工艺及机理.实验发现,软沥青非等温热聚合过程中甲苯不溶喹啉可溶物(TI-QS)含量呈抛物线型变化,在480℃～500℃之间出现极大值20.70%～24.38%.快速升温至340℃恒温热聚合,TI-QS含量变化同样呈现抛物线型变化,10h时存在极大值达37.49%.同时观察显微结构发现,在TI-QS极值出现之前中间相微球形成及生长,TI-QS极值出现之后中间相微球融并.因此可得出,制备高含量中间相预聚体的关键在于合理选择聚合温度和反应时间,选择相对较低温度,延长热聚合时间有利于制备高含量中间相预聚体.高含量中间相预聚体具有一定的流动性,在外力或流体流动的引导作用下能够实现有序融并,这为制取高质量的针状焦等新型炭材料提供了一条新的途径.

Mesophase pitch has been synthesized from coal tar pitch, in well-crucible stove. The techniques and pricinple preparation of pre-polymer with high-content mesophase, have been researched into through conversion rules of coal tar component and microstructure. During non-isothermal polymerization of coal tar pitch, TI-QS content changes as parabola, and its maximum（20.70 %-24. 38 %） appears in a narrow temperature range （480 ℃-500 ℃ ）. During thermal treatment of coal tar pitch to 340 ℃ and invariableness, TI-QS content also changes as parabola, its maximum（37.49%） appears at 10 h. By the observation of microstructure, nucleation and growth of mesophase spheres take place before appearance of TI-QS content maximum. the coalescence occurs after appearance of TI-QS content maximum. In conclusion, the key of preparation of pre-polymer with high-content mesophase is the selection of treatment time and temperature, and comparatively low treatment temperature as well as prolonged treatment time are propitious to preparation of pre-polymer with high-content mesophase. Pre-polymer with high-content mesophase is provided with rheology, therefore its coalescence in order could be carried out with induction of liquid flow or outside force. A new route to preparation of new type carbon material such as needle coke is discovered.