分散系にみられる非線形粘弾性

抄録

To determine non-linear viscoelasticity parameters for disperse and high-polymeric systems, the fundamental relations have been derived between these parameters and the experimental quantities by viscoelastometry, particularly with a torsionally oscillating rheometer, on the basis of the general theory presented by Green and Rivlin.
The non-linear viscoelasticity of several disperse systems consisting of polystyrene solutions and carbon black has been measured by means of the torsionally oscillating rheometer at various temperatures ranging from 100 to 220°C and in a frequency range from 4×10^-3 to 0.5 cycle per second. As a result of the harmonic analysis of the experimental results, it has been revealed that the resultant torque consists of the fundamental component and odd harmonics, and that the energy dissipated during one cycle is the same as that calculated from the fundamental component alone.
The frequency dependence curves at various temperatures for G₁' and G₁", which correspond to G' and G" for linear viscoelastic materials, can be superposed into master curves by horizontal and vertical shifts. The master curves manifest a plateau lower than the ordinary rubbery plateau on the low frequency side.