Preparation of mesophase pitch based graphite foams at atmospheric pressure

Abstract

Mesophase pitch based graphite foams have attracted an increasing attention because of their broad applications in thermal management, catalysis and so on. However, the common approach of high pressure method to fabricate graphite foams is complex and risky. Herein, the research reports a simple and relatively safe technique for preparation of mesophase pitch based graphite foams, which is conducted under atmospheric pressure.Through foaming of mesophase pitch in the presence of epoxy resin at 700°C under atmospheric pressure and graphitization at 3000°C, the graphite foam is fabricated.The obtained graphite foam is highly graphitic and has an open pore structure, the interlayer spacing of the (002) plane of which is about 0.3366 nm. Its density is 0.52 g/cm3 with a porosity of 73.5%. The properties of graphite foams can be tailored by pitch particle sizes and foaming temperatures. With the increase of pitch particle sizes from <25 to 75-150 μm or foaming temperatures from 400 to 850°C, the pore sizes vary from 10-25 μm to 35-90 μm, and their bulk densities change from 0.50 to 1.11 g/cm3. Also, a foaming mechanism is proposed that the residue of epoxy resin can form a framework during heating, in which the pitch softens and decomposes forming the foam. This study suggests a relatively simple and safe method for production of graphite foams from the mesophase pitch.