G. Bhatia et al., FORMATION OF MESOPHASE SPHERULES IN LOW-QL COAL-TAR PITCHES AND DEVELOPMENT OF MONOLITHIC CARBONS THEREFROM, Journal of Materials Science, 29(18), 1994, pp. 4757-4763
Three coal tar pitches having different and low contents of primary qu
inoline insolubles (QI) were subjected to a series of thermal treatmen
ts at a predetermined temperature for different periods of soaking. Th
e development of mesophase, in terms of its size and content in the he
at-treated pitches, was studied as a function of the soaking time and
content of primary quinoline insolubles in the original pitches. Mesop
hase spherules, with an average size of about 5 mu m, formed in one of
the coal tar pitches were separated using solvent extraction employin
g a suitable tar oil. These spherules, also called ''mesocarbon microb
eads (MCMB)'', after being moulded into small rectangular plates, were
carbonized at temperatures of 950 and 2700 degrees C to obtain fine t
extured monolithic carbons possessing apparent densities of 1.66 and 1
.85 g cm(-3), respectively, at these heat-treatment temperatures.