National Physical Laboratory

Rotational rheometry

Rotational rheometers can be used to determine transient and steady shear flow properties of materials; typically shear viscosity, creep or stress relaxation. Furthermore, the first and second normal stress differences, indicative of the elasticity of the material, can also be measured.

The principle, and often the instrument, is the same as for the oscillatory rheometer except that the deformation of the sample is obtained by rotating rather than oscillating one plate relative to the other.

The standard, ISO 3219, describes the measurement of shear viscosity. Such measurements tend to be limited to an upper shear rate of approximately 10 s-1 as at higher rates some of the sample can be ejected out from between the plates thereby critically changing the sample geometry.

NPL Facility: Controlled stress oscillatory rheometer covering a wide range of temperatures and shear rates, suited for measurement of stable and curing/degrading materials having viscosities in the range from approximately 1 mPa.s upwards.

Last Updated: 18 Aug 2016
Created: 1 Sep 2008


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