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Carbon foam is a sophisticated porous material with wide applications that depend on its structure, low density, thermal conductivity and electrical characteristics. This study deals with the preparation of carbon foam by the thermo-oxidative modification with HNO3 of mixtures containing different organic materials with appropriate chemical characteristics—furfural and tar pitch derived from RDF. Carbon foam is characterized by thermogravimetry, differential scanning calorimetry, elemental analysis, Raman spectroscopy, N2 sorption, infrared spectroscopy and scanning electron spectroscopy. The investigation of adsorption activity of carbon foam towards nickel (II) in water solution is carried out. Experimental results fit very well with the Langmuir adsorption model. The carbon foam, obtained from tar pitch derived from RDF and furfural, shows a high adsorption capacity towards nickel ions (203.67 mg/g). The high adsorption capacity could be explained by the properties of the adsorbent—moderately high surface area, micro-mesoporous texture and presence of oxygen-containing surface groups. [ABSTRACT FROM AUTHOR]

This work reports the microstructural evaluation of carbon foams derived from coal-tar pitch precursors treated with H 2 SO 4 and HNO 3 and finally annealed at 1000 °C and 2000 °C. Our experimental investigations combine scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) imaging, X-ray photoelectron spectroscopy (XPS) and micro-spot near-edge X-ray absorption fine structure (μ-NEXAFS) spectroscopy. This set of complementary techniques provides detailed structural and chemical information of the surface and the bulk of the carbon foams. The high-resolution microscopy data indicate the formation of carbonaceous amorphous microspheres (average diameters of 0.28 ± 0.01 μm) embedded in the partially graphitized carbon foam matrix at 1000 °C. The microspheres are enriched with sp-bonded species and their microstructural characteristics depend on the reagent (nitric vs. sulfuric acid) used for pitch treatment. A complete chemical transformation of the microspheres at temperatures >1000 °C occurs and at 2000 °C they are spectroscopically identical with the bulk material (sp 2 - and sp 3 -hybridised forms of carbon). The microstructure-property relationship is exemplified by the compressive strength measurements. These results allow a better description of coal-tar pitch-derived carbon foams at the atomic level, and may account for a better understanding of the processes during graphitization step. [ABSTRACT FROM AUTHOR]

Abstract: The steam activation of carbon foams obtained after thermo-oxidation treatment of coal tar pitch using inorganic acids (H2SO4 and HNO3), and subsequent low pressure foaming process without stabilization step, was investigated. The characterization of the activated carbon foams showed a strong dependence of the final structure of these materials from the chemical composition of the pitch precursor. This was related to the conditions of thermo-oxidation pre-treatment with inorganic acids, used to modify the composition of the initial pitch. In both cases carbon foams with uniform open cell structures were obtained, although they showed very different properties. When nitric acid was used in the initial thermo-oxidative treatment, the steam activation process of the carbon foam proceeded to a larger extent; the porosity parameters of this sample are twice higher than those obtained when using sulfuric acid. This was attributed to the catalytic effect of H2SO4 during the foaming step, which leads to the formation of dense carbon foams with highly ordered structure as inferred from XRD. At converse, densification of the carbon foam did not occur when using nitric acid in the initial thermo-oxidative treatment; the resulting material displayed labile surface groups decomposing at moderate temperatures, as well as an incipient microporosity, which further increased during the steam activation. [Copyright &y& Elsevier]

Carbon foam is an advanced porous material with multiple high-technology applications, due to its cell structure, light weight, high thermal stability, high thermal and electrical conductivity, as well as exceptional electromagnetic and acoustic properties. This work is dedicated to development of a new method for synthesis of carbon foam from a mixture of organic substances with suitable chemical properties and appropriate oxidation treatment, which allows synthesis of foam without the use of high pressure and stabilization step. The appropriate treatment conditions (thermo-oxidative modification with conc. H 2 SO 4 or conc. HNO 3 of mixtures of furfural and industrial coal tar pitch in different proportions), allowing the formation of porous structure of the resulting carbon foam, are established. The properties of the synthesized carbon foam can be controlled by varying the composition of the starting mixture and the type of oxidant. The formation mechanism of the porous structure of carbon foams is considered. Obtained carbon foam samples are characterized by XRD, Scanning Electron Microscopy, TG and DSC analysis, elemental analysis. The proposed new, less energy consuming synthesis method enables the production of carbon foam with very good physico-chemical properties. Unlabelled Image • Graphite carbon foams are synthesized from mixtures of organic substances. • The precursor mixture is composed of furfural and industrial coal tar pitch. • The precursor is subjected to thermo-oxidative modification with H 2 SO 4 and HNO 3. • Modification method allows avoiding the use of pressure and stabilization step. • The synthesized material has very good physico-chemical properties. [ABSTRACT FROM AUTHOR]

The effect of dimension of carbon foam (CF) grains used as a filler of epoxy matrix on the morphology and thermomechanical and tribological properties of final composites was described. The carbon foam proposed as particle reinforcement of composites was prepared from epoxy resin of diglycidyl ether of bisphenol A type cured with phenol-formaldehyde resin (novolac) in a self-foaming process followed by carbonization. Structures of the carbon foam filler and resultant composites were studied by microscopic and spectroscopic methods. Three different carbon foam grain fractions, below 200 μm, 200–315 μm and below 315 μm, keeping CF porous structure and specific properties, were used to obtain new composite materials. There were observed good quality dispersion of CF grains in epoxy matrix and excellent adhesion at interfacial areas, regardless of carbon foam fraction. In the effect, these composites have enhanced thermomechanical and tribological properties and relatively low density compared to carbon-polymer composites produced so far. It was found that all CF fractions used reduced friction coefficient of resultant composites compared to pure epoxy matrix, however the influence of individual filler fraction on composite's COF was different. The morphology of worn surfaces of epoxy composites after friction tests showed that the effect depends on grain fraction of CF filler as well as on the load used. • Carbon foam grains as reinforcement of epoxy matrix were used. • Carbon foam fraction had an effect on thermomechanical properties of composites. • Dependence of composites friction coefficients on foam grain fractions was found. • Epoxy composites with various foam fractions showed different wear characteristics. [ABSTRACT FROM AUTHOR]