Preparation Of Carbon Foam Based On Resins As Precursors

Carbon foams are a new class of porous lightweight carbon materials with certain features, such as light weight, high temperature tolerance, high strength, large external surface area with open cell structure, and adjustable thermal and electrical conductivity. The potential applications of carbon foam include such diverse areas as high-temperature thermal insulation, high thermally conductive heat sinks, electrodes for energy storage, energy absorption material, catalyst supports and filters, etc. Therefore, many practical potential uses are laid in carbon foams. However, few of references on carbon foams were reported, most of which are patents. It is obviously important for us to carry on this research, which will be much better if it can be put into industry.Two materials regarded as precursors are made into carbon foams in this paper by using different methods.Phenolic resins foams were prepared in high-pressure autoclave by employing phenol formaldehyde resin as precursor, pentane as the blowing reagent and Tween-80 as foam stabilizers. Then the phenolic foams were carbonized at 1000℃ to produce carbon foams. The thermal stability of phenolic foams, the microstructure and crystal structure of the resultant carbon foams were characterized by thermal gravimetric analysis (TGA), scanning electron microscope (SEM) and X-ray diffraction (XRD). The results indicate that as-prepared carbon foams are porous amorphous carbon materials with very light bulk density of about 0.15 g·cm^-3. The influence of depressurization rate of high-pressure autoclave on the structure of carbon foams was investigated. The results show that carbon foams of interconnected pore and uniform pore size were obtained by controlling the depressurization rate of 0.05MPa·min^-1.