论文部分内容阅读
以煤焦油沥青为原料 ,鳞片石墨为添加剂 ,在 4 10℃温度下反应 7h制得了中间相炭微球 (MCMBs)。在扫描电子显微镜下对它们的表面和断面进行了分析 ,并用X射线衍射对其结构进行了研究。结果表明 :MCMBs的表面被接近球形的小颗粒所覆盖而呈现出粗糙不平。MCB1(未加石墨 )的织构主要是平行层型 ,而MCB2 (加石墨 )的织构却是复杂的。加入煤焦油沥青中的大片石墨存在于MCMBs的中心而被认为是它们的核 ,而小片石墨却不能象大片石墨那样在反应体系内充当核的作用。认为在成核过程中 ,大片石墨聚集到一起而形成晶种 ,同时一些低分子量的沥青组分被包裹在这些晶种的内部 ,石墨片以及它们的积聚体的形状、大小决定了MCMBs的织构。然而 ,小石墨片只能使MCMBs的织构变得杂乱。MCMBs的XRD谱图表明石墨的添加改变了其结构 ,并降低了它的石墨化能力和晶体大小。
The mesocarbon microbeads (MCMBs) were prepared by using coal tar pitch as raw material and flake graphite as additive, and reacting at 4 10 ℃ for 7h. Their surface and cross sections were analyzed by scanning electron microscopy and their structures were investigated by X-ray diffraction. The results show that the surface of MCMBs is covered with small particles close to spherical shape, showing rough appearance. The texture of MCB1 (without graphite) is mainly parallel and the texture of MCB2 (plus graphite) is complex. Large pieces of graphite added to coal tar pitch are present in the center of the MCMBs and considered as their nuclei, whereas small pieces of graphite do not act as nuclei in the reaction system as large pieces of graphite. It is considered that during the nucleation process, large pieces of graphite are aggregated together to form seeds while some low-molecular-weight bitumen components are entrapped inside the seeds. The shape and size of graphite sheets and their aggregates determine the weaving of MCMBs Structure. However, small graphite sheets can only mess the texture of MCMBs. The XRD patterns of MCMBs show that the addition of graphite changes its structure and decreases its graphitization capacity and crystal size.