A comparative study on the development of pitch precursor for general-purpose carbon fibres

A comparative study on the development of suitable pitch precursor from coal tar pitch and a petroleum pitch was carried out using the techniques of condensation, polymerisation and distillation. The properties of modified pitch blend resulted from the combination of the petroleum and coal tar pitch in a suitable ratio were compared from the pitches obtained from coal tar and petroleum pitch alone, to find an appropriate condition of preparing isotropic pitch for general-purpose carbon fibres. The effect of various processing parameters, namely temperature, time and atmosphere (inert/partial vacuum) on the characteristics of the pitches was studied. The study revealed that neither a coal tar pitch nor a petroleum pitch, alone, can lead to a high softening point as well as high coking value pitch without mesophase contamination, under thermal conditions. Whereas, proper blending of these two proved to be an efficient method to prevent the mesophase growth along with an increase in the other desired properties under same conditions.