New Techniques for Measuring Complex Shear Viscosity of Dilute Polymer Solutions at Frequencies from 2 to 300 kHz

Abstract

Two new techniques for measuring complex shear viscosity (r/-irJ'') of a liquid, especially of a dilute solution of polymer including polyelectrolyte, have been developed. The first of them, "the travelling torsional wave method", consists essentially of measuring incremental attenuation and phase retardation of torsional waves travelling along a long circular rod when a liquid is applied around the rod. The waves are generated and received by a quartz torsional resonator soldered on the top of the rod. ' Electronic circuits are designed so as to observed frequency ranges from 20 to 300kHz and the error is within 1% for the sample with the viscosity of I0-2 poise. A sample of 10 cc is required for the measurement. The second method, "the torsional reverberation method", employs the same vibration system as the above but the system is excited into a resonant oscillation. The method consists of measuring decrease in resonant frequency and increase in decay-rate when a liquid is applied around the rod. The method can be used at a fundamental resonance and overtones, 2 to 10kHz in the present case. The accuracy is of the order of 1% for the sample with viscosity of I0-2 poise. KEY WORDS Complex Viscosity I Technique I Polymer Solution I Polyelectrolyte I 2-300kHz 1 A technique for measuring complex shear viscosity of a liquid was first proposed by Mason 1 who measured variation in resonant frequency and equivalent resistance of a torsional quartz resonator when the liquid was applied. The method covered the frequency range from 20 to 200 kHz by use of resonators of different length. Torikai and Negishi" employed a phase-sensitive detector for measuring the equivalent resistance of the resonator. Application of this technique to dilute polymer solutions was made by Tanaka, Sakanishi, and Furuichi. 3 One of the present authors (Wada) and his coworkers 4 employed a modification of this method, which is applicable to an electrically conductive liquid. In this case, the lower one-fourth of the resonator was dipped into the liquid.

Bulk rheometry at high frequencies: a review of experimental approaches

“…The fluid impedance Z f (12−13) could be derived semiempirically from the measured attenuation and phase shift of the wave after reflection from the free end. Excitation and detection are carried out either using piezoelectric or magnetostrictive materials (McSkimin 1952;Nakajima and Wada 1970;Glover et al 1968;Poddar et al 1978). While most setups make use of immersed rods, hollow tube instruments with increased sensitivity and reduced sample volume were developed as well (Glover et al 1968).…”

Measurement of Viscoelastic Properties of Polymer Solutions by Torsional Crystals

“…25, No. 6,1993 instrument to measure the viscoelasticity of polymer solutions precisely using torsional crystal. From the results it is found that the complex shear modulus of polystyrene in toluene can be explained by Rouse theory, when the concentration is smaller than the critical solution and the values of WT 1 are below 102.…”

Automatic apparatus, based upon a nickel-tube resonator, for measuring the complex shear modulus of liquids in the kHz range

“…As a consequence of [5] and using the antisymmetry of the problem, 0(0) = O, [13] the following solution of [7] for 0 < z < L/2 is obtained:…”

“…This method offers a continuous frequency fange and enables the measurements of viscoelastic data of electrically conducting liquids. Combining this geometry with a resonance method the frequency range can be extended at the lower side (7,8,9).…”