ISSN 0020-1685, Inorganic Materials, 2014, Vol. 50, No. 4, pp. 344–348. © Pleiades Publishing, Ltd., 2014. Original Russian Text © V.M. Ogenko, L.V. Dubrovina, O.V. Naboka, I.V. Dubrovin, 2014, published in Neorganicheskie Materialy, 2014, Vol. 50, No. 4, pp. 372–376. 344 INTRODUCTION Carbon-based composites are already in practical use as sorbents, catalysts of chemical reactions, and anodes of lithium ion batteries and are potentially attractive as magnetic, electrically conducting, and heat-conducting materials. The fabrication of com- plex-shaped high-temperature heaters (including flexible configurations), pipes for aggressive media, and high-temperature thermal shields is based on the use of carbon–carbon–carbon–carbon composites: C(exfoliated graphite)–C(pyrolytic carbon)–C(car- bon fiber)–C(pitch etc.). Exfoliated graphite (EG) is a relatively new carbon material, which possesses all the properties of graphite but has a very low bulk den- sity, large specific surface area, and high plasticity. EG is characterized by a small thickness of stacks of graphene layers (20–70 nm) and a high concentration of pores 2–5 nm in size. Owing to the presence of nan- opores, EG-based composites can be thought of as promising sorbents, membranes, and hydrogen stor- age materials. Moreover, when EG is used as a matrix, its structural characteristics can be varied via modifi- cation with pyrolytic carbon [1–6]. Several groups [7– 9] have studied the synthesis conditions, structure, and properties of EG having metal or metal oxide nanoparticles supported on its surface, which increase the capability of the material for adsorption, ion exchange, and atomic exchange. The use of microporous carbon–carbon materials is currently limited by their high cost, so the ability to reduce their cost remains a priority issue. The purpose of this work was to fabricate carbon– carbon composites based on exfoliated graphite mod- ified with pyrolytic carbon produced via carbonization of organic and polymeric precursors. EXPERIMENTAL As a carbon support for the preparation of pyrolytic carbon nanostructures, we used exfoliated graphite (EG) (Sivash Pilot Works, Chuiko Institute of Surface Chemistry, National Academy of Sciences of Ukraine). The following carbon precursors, chosen based on previous results [10, 11], were used: (1) com- mercially available poly(vinylidene fluoride) (PVDF) with a characteristic viscosity [η] = 1.2 dL/g, as deter- mined at 25°C in dimethylformamide (DMFA), and samples consisting of PVDF and a cobalt(II) chloride solution in DMFA; (2) a mixture of tolylene 2,4-diiso- cyanate (70 wt %) and tolylene 2,6-diisocyanate (30 wt %) (TDI); and (3) IsoPMDI92140 polyisocy- anate (PIC) (Elastogran, Germany), which is a mix- ture of 4,4'-diphenylmethane diisocyanate with highly functional oligomers and isomers (average functional- ity, 2.7; concentration of NCO groups, 31 wt %). A PVDF solution (4.0 g/100 mL) and TDI and PIC solutions in DMFA were used to impregnate EG (at room temperature). The precursor : matrix ratios were [PVDF] : [EG] = 1 : 4, [TDI] : [EG] = 1 : 10, and [PIC] : [EG] = 1 : 5 by weight. Dried samples were carbonized at 750°C in flowing argon. The samples were characterized by scanning elec- tron microscopy (SEM) on a Carl Zeiss Leo Ultra 55 FEG SEM. Before SEM examination, the samples were applied to a double sided conductive adhesive tape. The accelerating voltage was 1.5–2.0 kV. The surface topography of the samples was examined in secondary-electron mode. The compositional con- trast was estimated using an EsB low-energy back- scattered electron detector (filtering grid voltage, 1.3– 1.5 kV). The composition of the carbon samples was determined by energy dispersive X-ray (EDX) spec- 1 Exfoliated Graphite Modified with Pyrolytic Carbon V. M. Ogenko a , L. V. Dubrovina a , O. V. Naboka a , and I. V. Dubrovin b a Vernadsky Institute of General and Inorganic Chemistry, National Academy of Sciences of Ukraine, pr. Akademika Palladina 32/34, Kyiv, 03680 Ukraine b Chuiko Institute of Surface Chemistry, National Academy of Sciences of Ukraine, vul. Generala Naumova 17, Kyiv, 03164 Ukraine e-mail: divexfoliated@ua.fm Received June 27, 2013 Abstract—Exfoliated graphite (EG) has been modified with pyrolytic carbon produced by 750°C carboniza- tion of poly(vinylidene fluoride) (PVDF), tolylene diisocyanate (TDI), and polyisocyanate (PIC) applied to the EG surface from solutions. The pyrolytic carbon obtained had the form of particles ranging in size from 200 nm to 1 μm. The microstructural characteristics of the carbon–carbon materials depend on the chemical composition of the carbon precursor: S = 15.8 to 63 m 2 /g; nitrogen sorption from 24.7 to 59.2 cm 3 /g (– 190°C); micropore volume, up to 7.4 mm 3 /g; benzene vapor absorption from 0.07 to 0.27 g/g (20°C). DOI: 10.1134/S002016851404013X