ELABORATION AND STRUCTURE OF SILICATE CARBON LAMELLAR NANOCOMPOSITES/

The interlamellar cations of Na-montmorillonite and Li-taeniolite were exchanged for aromatic ammonium cations (acriflavine, aminoacridine, safranine, indoine) to lead to silicate-organic cation complexes. The subsequent thermal treatment of the complexes, under neutral atmospher e, led to the lamellar silicate-carbon nanocomposites. X-ray diffracti on measurements on the silicate-organic cation complexes demonstrated that the organic cations are perpendicular to the silicate sheets, but slightly tilted. The nanocomposites were formed when carbonization of the interlamellar organic cation started, i.e. at 400 degrees C. Tran smission electron microscopy observations strongly suggested that, at 400-500 degrees C, basic structural units (BSUs), stackings of two or three aromatic carbon layers of nanometric dimensions, are formed, and are almost randomly distributed in the interlayer space of the nanoco mposite. Upon increasing the heat treatment temperature, the interlaye r distance d(001) in the composite decreases, and due to the lattice c onstraints, the BSUs tend to become more and more parallel to the sili cate sheets. Above 1000 degrees C, the highly dispersed carbon starts to react with the silicate host, and through carbo-reduction a ceramic material can be formed.