Preparation of Mesophase Pitch-Based Carbon Foams with Supercritical Toluene

Mesophase pitch-based carbon foams were prepared with supercritical toluene. The effects of the foaming conditions, such as the solvent proportions, temperatures, initial pressures, and pressure drop rates, on the cell densities and mean cell diameters of the carbon foams were studied. The foaming mechanism was analyzed with the theories of homogeneous nucleation. The carbon foams varied in cell densities and cell structure from three-dimensional interconnected to closed sizing in the range 200 to 800 mu m when they were generated under different conditions. The carbon foam structure could be optimized with cell densities of 10-16 x 10(3) cm(-3) and cell diameters from 400 to 450 mu m, under the conditions where the temperature was 588 K, the initial pressure was 3.0 MPa, the pressure drop rate was 1.5 MPa/s, and the solvent proportion was 30 wt %. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 336-341, 2011