Effect Mechanisms of Carbon Nanotubes on the Supercritical Foaming Behaviors and Mechanical Performance of Carbon Foam

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 proc-ess,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 mechani-cal strength of pore walls and ligaments.