Theoretical and experimental investigation of shearing in elastic polymer liquids

Abstract

In the present paper a rheologic theory (1) has been compared to results of different shear experiments in the region of moderate elastic strains using a polymer solution as an example. The 40% butyl rubber solution (M ≈ 3 {dot operator} 104) in transformer oil has been employed as tested liquid. A major part of the experimental data has been obtained on the Weissenberg Rheogoniometer. The three and five constants rheologic models (the first and second approximations) have been discussed. Model constants have been defined in the linear region of the rheologic behaviour of the solution using dynamic characteristics. The theory has been compared to experiments employing the steady rheologic characteristics (dependence of tangential stress and the two differences of normal stress on shear velocity), transition to steady flow (under the condition of constant shear velocity) and relaxation of tangential and normal stresses from steady flow using the "cone-plate" and "disk-disk" units, generation of steady flow under the condition of constant tangential stress and aftereffect strain, superposition of small oscillations on the non-linear steady shear flow. It was shown that taking the experimental data in total, the theory is in satisfactory agreement with the experiments both for the first and second approximations. In all cases considered, the second approximation theory is in better agreement with the test then the first one. © 1976 Dr. Dietrich Steinkopff Verlag.