Determination of viscoelastic properties of pitches by torsional creep

摘要: Abstract Creep behavior of a petroleum pitch and two kinds coal tar pitch, as they are mixed in various portions, were studied by measuring the torsional creep at temperatures 30–90°C. The pitches used viscoelastic, viscous elastic terms separately evaluated from steady state viscosity η compliance J e o . shows negative temperature dependence, which activation energy for flow is found 63 kcal/mol all used. , increases with increase temperature. This indicates importance inter- intra-molecular potential elasticity pitch. A time-temperature superposition rule was to be satisfactorily applicable data observed. rheological meaning softening point discussed, differences emphasized. Viscoelastic analysis useful giving important parameters characterization pitch-like materials.