Study of multiwalled graphite nanotubes and filaments formation from carbonized products of polyvinyl alcohol via catalytic graphitization at 600-800degrees C in nitrogen atmosphere

The catalytic graphitization of amorphous carbon matrix was carried out at the temperature range of 600-800 degrees C in nitrogen atmosphere. Amorphou s carbon matrix with uniformly distributed Fe particles was obtained via ca talytic carbonization of polyvinyl alcohol (PVA) at temperatures up to 600 degrees C in nitrogen atmosphere. Using transmission electron microscopy (T EM), selected area diffraction (SAD), scanning electron microscopy (SEM), a nd X-ray diffractometry (XRD), graphite structures of three types were foun d in products of catalytic graphitization of amorphous carbon matrix: multi walled graphite shells wrapping the catalyst particles, cockle-shelled grap hite filaments (CSF), and multiwalled graphite nanotubes (MWNT). We suppose that the formation of CSF proceeds through the dissolution of amorphous ca rbon in the metal, transformation of the catalyst particles into a liquid s tate, and transfer of dissolved carbon via intermediates to growing filamen ts. Graphite nanotubes nucleate at the matrix surface and then grow in the porous space of the matrix. (C) 2000 Elsevier Science Ltd. All rights reser ved.