| Carbon foams are porous and sponge—like carbon materials with many novel features such as high temperature tolerance, adjustable thermal and electrical conductivity, and large specific surface area with open cell structures. These materials are attractive and promising candidates for use and application in, for instance, thermal management, microwave absorption, supercapacitors, aircraft brakes, catalytic support and electrodes and so on.Different methods of preparation of carbon foam, such as foaming method, hard-templating method and soft-templating method have been discussed here. IR, TG, SEM, BET, XRD, etc have been carried out to characterize the properties and structures of carbon foams.In the foaming method, hydroxyphenol-formaldehyde resin was used as the carbon sourse and foaming agent method and supersonic foaming method have been adopted to make pores in the systems. The carbon foams forerunner have been obtained after the hardening of the systems, and carbon foams have been got after carbonization. Meanwhile, RF foam has been carbonized directly to compare with the other two kinds of carbon foams. Through these ways of foaming method, open-cell carbon foams with their pore diameter been 50-100, 100-200, 100-130μm and the specific area been 591, 516, 297m~2/g have been fabricated. The mechanism of the foam forming has been discussed in the paper.In the hard-templating method, silicon sol has been adopted as the template material and hydroxyphenol-formaldehyde resin as the carbon sourse. After mixing all the initial materias thouroughly, hardener was added in to solidify this system. This hardened system was carboniazed after immersing and washing stratage. The product has been characterized by IR, SEM, BET, and XRD. Carbon foam with specific area of 300-700 m~2/g and multilevel pore structure has been fabricated. The size of the macro-pore was distributing in 5-20μm and the micro-pore in 4nm or 10-15nm. Effects on the carbon foam structures under different situations have been discussed when factors changed, which included the solvent phase, the way of solidification, the amount of harden agent, ethanol as solvent phase, acetone as solvent phase, the use of surfactant, and the proportion of oil phase. The causes of the forming of different pores have been deduced in this section. Macro-pore was derived from the volatilization of the water in the hardening and drying stratage; and the micro-pore was derived from the silicon template after its removing.The soft-templating method included emulsion templating method and surfantant templating method. The products have been characterized by SEM, BET, and TEM. And the causes of different pore structures have been discussed in this chapter. A system of hydroxyphenol-formaldehyde resin/liquid paraffin/surfantant has been introduced to prepare the carbon foam and the products of the specific area been 700m~2/g and the pore size distributed in 2-3μm and 0.5-1μm have been synthesized in the emulsion templating method. The cause of the macro-pore in this carbon foam was the removing of the liquid paraffin, and the cause of the micro-pore was the self-assembling and then removing of the surfactant. In the surfanctant templating method, the system of hydroxyphenol-formaldehyde resin/surfantant has been adopted and the carbon foam with 670m~2/g in its specific area and 4nm in its pore diameter has been fabricated. The pore in this carbon foam was derived from the self-assembling and then removing of the surfactant.
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