Pitch terms Links

This phase transition is initially reversible, as demonstrated by Lewis (10), but as carbonization progresses chemical cross-linking makes it irreversible The liquid crystal droplets grow and coalesce until all the isotropic melt has undergone the phase transition This new phase is then termed the liquid crystal mesophase, i e the phase intermediate between the isotropic fluid pitch and solid semi-coke ... 

This research by Dumont et al. (2002) describes the development of Raman spectra from a parent pitch to a resultant coke. The RMS spectrum of the coke originates from within one (embryonic) graphene layer which most probably forms part of a cross-linked carbon network. The proposed existence of a graphitic crystallite" composed of several grapherte layers stacked parallel to each other is not required. Hence, the frequent use of the term "graphitic microcrystallite within the RMS literature is simply an uncritical carry-over of words from WAXD studies and which unfortunately impart seriously misleading ideas. 

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