Method of Viscoelasticity Measurement under Shear-Flow

Abstract

In anticipation of that direct examination of the shear flow affection on the dynamic viscoelasticity might bring more comprehensive results than the LAOS method, a series of dynamic viscoelasticity measurements with parallel superposition of steady shear flow was planned. The measured values which are function of shear rate ̇γ, that is, storage and loss moduli G′(̇γ), G″(̇γ) and viscosity η(̇γ), are analyzed as three non-dimensional parameters G′(̇γ) / G′(0), G″(̇γ) / G″(0) and η(̇γ) / | η*(ω, ̇γ) |, where η* is complex viscosity. A Couette rheometer ONRH-1b (OhnaTech) was employed, and for the samples, hydroxypropyl cellulose, xanthan gum, carboxyvinyl polymer and C24-hydrophobically modified ethoxylated urethane ware used. All three analyzing parameters show clearly the differences of samples. It is found that the nature of their responses are subjected not by the shear itself, but by the value that divided shear rate with measure frequency (̇γ/ω). On the other hand, it is found that the properties that are subjected by the shear rate do exist. Observation of these results asserts that multifactorial rheological measurement including this superposition method is worthwhile.