采用超声波?磁力搅拌的方法, 实现了纳米碳管(CNTs)在中间相沥青(MP)中的均匀分散, 并考察了CNTs对泡沫炭的超临界发泡行为及其压缩强度的影响. 研究结果表明: 在超临界发泡过程中, 处于过饱和状态的甲苯将优先在CNTs/MP固-液界面处成核, 进而不断扩散、聚集、膨胀和发泡, 导致泡沫炭孔结构的均一性得以提高; 当在中间相沥青中均匀分散3.5wt%的CNTs后, 所制泡沫炭的压缩强度由3.2MPa提高到4.7MPa, 升高了46.9%; CNTs良好的导热性能降低了基体碳在石墨化过程中的热应力差异, 使得微裂纹的数量减少, 并且其一维纳米结构使得石墨化泡沫炭的孔壁和韧带结构得以增强.
Carbon nanotubes (CNTs) were dispersed uniformly into mesophase pitch (MP) by the co-dispersion of ultrasonic and magnetic force stirring. Effects of CNTs on the supercritical foaming behaviors and mechanical performance of carbon foams were investigated. The results indicate that cell nuclei will form firstly at the CNT/MP interface in the supercritical foaming process, and then diffuse, aggregate, expanse and foam. CNTs can improve the homogenicity of pore structure due to the uniform dispersed CNT/MP interface. When MP is mixed with 3.5wt% CNTs, the compressive strength of graphitized foam increases from 3.2MPa to 4.7 MPa. In the graphitization process, the heat-stress different of carbon will decrease due to the high thermal conductivity of CNTs, leading to the decrease of the amount of microcracks. Meanwhile, the one-dimensional structure of CNTs reinforces the mechanical strength of pore walls and ligaments.
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