Rheological investigations of pitch material: Part II: viscosity measurement of A240 and ARA-24 pitches using a high-temperature high-pressure rheometer Original Research Article

Fluid behavior of carbonaceous pitch materials, such as A240 and ARA-24, is evaluated using the high-temperature, high-pressure (HTHP) viscometer. The measured viscosity of A240 pitch using the HTHP viscometer shows excellent agreement with that obtained using a Brookfield viscometer (DV III+). Further, the viscosity of ARA-24 (mesophase) pitch is measured and reported as a function of temperature at elevated temperature. Finally, the viscosity of pitch materials, both A240 and ARA-24, is modeled using the modified William–Landel–Ferry (WLF) equation. The shear activation energy for the 100% mesophase pitch (ARA-24 pitch) increased with the shear rate while that for the A240 pitch remained constant. Moreover, the shear activation energy for ARA-24 pitch was higher than that for A240 pitch at the shear rates investigated.