Brief introduction of expanded graphite

Graphite is a two-layered structure of macromolecules, each in the plane of the c atoms are combined to c c Covalent bonds, combined with the weak van der Waals forces between the layers. Graphite of layer-like structure is typical, each layer tablets is a carbon atomic layer, layer within carbon Atomic Zhijian to SP2 miscellaneous of track into is strong of Covalent bonds, that 1 a 2s electronic and 2 a 2p electronic miscellaneous of equivalent of miscellaneous of track, is located in same plane Shang, each other formed σ key, and two a not participate in miscellaneous of of 2P electronic is vertical Yu plane, formed two key π. This layered structure made of graphite there is a certain gap between layers. Under certain conditions, therefore, some reactant (such as acid, alkali, halogens) atoms (or individual) to enter the interlayer space and plane formation and carbon NET compound. This plug is expandable graphite graphite intercalation compounds. Very weak van der Waals forces between the carbon atoms linked, this structure allows the intercalation substance can smoothly enter the carbon the original layer without disturbing the layers of carbon atoms in hexagonal mesh, natural graphite is the best parent material preparation of graphite intercalation compounds. Graphite is a physical or chemical methods of non-carbon reaction inserted between the graphite layers, carbon hexagonal plane combined with the network while maintaining the graphite crystals with layered structure compounds. It has not only kept excellent physical and chemical properties of graphite, and because of the inserted material and interaction between graphite layers and shows the original graphite intercalation substance and does not have new features. Plug the graphite intercalation compounds in case of high temperatures, interlayer compounds will decompose along the c-axis direction of thrust between the graphite layers, this force much larger than the force of graphite particles, under the thrust of graphite intercalation is pushed so that the graphite particles along the c axis high expansion and formation of expanded graphite worm-shaped L2]. Between graphite can be "embedded" into the expansion of the chemical. By sulfuric acid treatment of graphite, graphite at elevated temperatures expansion after drying, this is because of the sulfuric acid molecule "embedded" into the graphite layers.