Preparation of mesophase-pitch-based carbon foams at low pressures

A simple method for preparing the mesophase-pitch-based carbon foams at low pressures through prolonging the soaking time in the preparation process of the mesophase pitch was disclosed. The physical properties, morphologies and the crystal structure of the as-obtained foams were investigated. Bulk density of the resultant carbon foams cover a range 0.514–0.624 g/cm3, under the preparation pressure range 0.5–2 MPa. The SEM micrographs revealed that the thermal shrinkage of the graphitized foams derived from the higher softening point mesophase pitch was less than that of the foam from the lower softening point; Optical micrographs showed that higher softening point mesophase pitch derived carbon foams exhibited better orientation and less microcracks in both junctions and ligaments; The XRD results revealed that higher softening point pitch derived graphitized foams exhibited smaller interlayer spacing and larger crystallite size. The properties of the carbon foam can be severely affected by the properties of the precursor, so it is critical to tailor the properties of the pitch precursor so as to obtain high performance and low cost products.