烷基在针状焦形成中的作用

采用煤焦油沥青的甲苯可溶物和废聚苯乙烯共碳化制备针状焦，考察了中间相沥青中烷基含量对针状焦性能的影响。结果表明，通过添加废聚苯乙烯共碳化,中间相沥青中烷基的质量分数从12.0%增加到33.3%，可以制备出热膨胀系数更低、光学各向异性排列更好的针状焦。代表光学各向异性指数的两个量,在光学结构单元中，平行于热膨胀系数方向的轴向分矢量平均长度和光学结构单元的矢量平均长度，分别从20.8μm 和23.4μm增加到28.4μm和28.8μm，热膨胀系数从0.8×10^-6 /K降低到0.1×10^-6 /K。针状焦形成过程中中间相沥青的烷基含量增加使体系黏度降低，有利于光学各向异性相的融并和定向排列。烷基的增多在固化阶段产生足量的气体，在向外逸出过程中使融并中间相的芳香平面大分子沿轴向排列的更为规整。

Influences of alkyl group on the formation of needle coke

Needle coke was prepared through the co-carbonization of toluene soluble fraction(TS) of coal tar pitch and waste polystyrene(WPS) in a tube bomb.The effects of the content of alkyl groups in the mesophase pitches on the properties of needle coke were investigated.By adding WPS into TS,the alkyl content in the mesophase pitches is increased from 12.0% to 33.3%;the resultant needle coke exhibits lower coefficient of thermal expansion(CTE) and better anisotropic orientation.The anisotropic indices of average ...