Study on rheological properties of coal tar pitch modified with terephthalic aldehyde

In order to study the rheological properties of coal tar pitch modified with terephthalic aldehyde (TPA), the apparent viscosity of parent coal tar pitch and that of the modified coal tar pitch were measured using rotating coaxial-cylinder viscometer; thermal behavior of the pitches was analyzed with differential scanning calorimetry (DSC). The experimental findings are as follows: (1) The curve of the relations between the viscosity and temperature is the 'W' profile. There is low viscosity flow area at 200~225°C in the modified coal tar pitch. The apparent viscosity is 200~400 mPa · s. (2) The viscous activation energy of the modified coal tar pitch is lower than that of parent coal tar pitch, which is beneficial to the process for producing carbon materials. (3) The apparent viscosity of the modified coal tar pitch increases rapidly after 225°C which would make the modified coal tar pitch not flow backwards during impregnation and carbonization.