Abstract:
Pyrolysis of pyrene has been carried out to examine whether it is possible to
produce condensed planar sheets of aromatic rings toform graphite and also to
investigate whether the degree of graphitization relatively increases compared
with other lower aromatic ring compounds or not. In the initial stages of
nucleation and growth, a liquid-state mesophase of optical anisotropy appears
as spherules in the sample. As carbonization progresses, the growing
mesophase spherules change in shape in forming relatively complex bulk
mesophase and mosaic texture. Reflected polarized-light micrography using
cross polarizers with a gypsum plate at 45° with one of the polars [Sensitive Tint
Technique] has been employed to investigate the microstructure of
carbonaceous mesophase displaying maltese cross patterns and nodes as well
as mosaic texture. Differential thermal analysis has been employed to locate the
temperature region of mesophase formation. Thermogravimetric analysis has
been used to see the quantitative analysis of the sample and to calculate the
dynamic weight loss of the sample during carbonization. Interlayer spacing
calculated from the X-ray diffractograms of the carbonized samples is found to
decrease with heat-treatment temperature and duration. A comparative study
has been carried out with the interlayer spacings of some lower aromatic
compounds under. similar condition. IR spectra have been used to substantiate
the above results about the structural modifications of the carbonized samples.
The broadening of the peak area of the aromatic band by IR study reveals about
the order of the degree of graphitization.
