Birefringence in a strained viscoelastic fluid under steady-state rotary conditions. II
✍ Scribed by Gill, Stanley J. ;Dintzis, Frederick R.
- Publisher
- John Wiley and Sons
- Year
- 1962
- Weight
- 563 KB
- Volume
- 57
- Category
- Article
- ISSN
- 0022-3832
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✦ Synopsis
Abstract
A rotary strain device for introducing a calculable amount of strain into a viscoelastic fluid under essentially zero flow conditions has been built and tested. The principle of the device is based upon the continuous deformation of a flexible Teflon tube which is rotated within a closely fitting, stationary, rigid metal tube that has an elliptical cross section. A polymer solution placed in such a rotating tube is subjected to an alternating strain and rotation of the bulk material. Under such conditions a steady‐state situation occurs where the material has well defined anisotropic properties. This anisotropic state is characterized by measuring both the retardation and orientation of the principle axes of the induced birefringence with a Soleil Babinet compensator. Measurements made on fluid systems at rotations of approximately 50–400 rpm yield experimental results that agree with general theoretical requirements. Mooney has analyzed the analogous situation of a microscopic rotating region. This analysis, when applied to measurements made in the rotary strain device, permits calculation of functions proportional to the storage modulus, the loss modulus, and the relaxation function of the polymer. Measurements and calculations are presented for carboxymethyl cellulose solutions in water.