Dynamic modulus of polyisobutylene solutions in superposed steady shear flow

Abstract

Measurements are reported for the first time of the effect on the dynamic modulus of a viscoelastic liquid of the superposition of a steady shearing orthogonal to the oscillatory shearing. The author believes that the study of this flow, together with the case of parallel superposition of a steady and an oscillatory shearing, will clarify the importance of the second invariant of the rate of deformation tensor used in a number of rheological equations of state for viscoelastic liquids. 8.54, 6.86 and 5.39% solutions of polyisobutylene in cetane were studied using a recently developed electromagnetic transducer over the frequency range 0.3 to 150 c.p.s. Preliminary experiments on the orthogonal superposition of two oscillatory shear flows are also reported.