A distinction is made between rheometers according to the type of force exerted in or on the sample to be measured. In a rotational rheometer, a measuring body rotates in a sample in one direction around an axis. In the capillary rheometer, the sample is pushed through thin capillary nozzles and their throughput time is evaluated.
NETZSCH offers both!
NETZSCH is the only company on the market, offering both types of rheometer and, in combination with other thermal analysis instruments, creates far-reaching analysis possibilities from a single source.
The shear rate, which is of great interest for rheological measurements, is dependent on the application. Spraying, for example, requires high shear rates, other applications such as sedimentation are related to low shear rates. Accordingly, the choice of the rheometer depends on the required shear rate. While the Kinexus, as a rotational rheometer, is the instrument of choice to measure in the low shear rate range, one will work with a Rosand capillary rheometer to reach high shear rates up to 1,000,000 s-1.
With the unique combination of rotational and capillary rheometer measurements offered by NETZSCH, a very broad shear rate range is achieved. This is important, for example, for the analysis of polymers because their behavior depends strongly of the shear rate to which they are subjected.
In our latest application note, we obtained the viscosity curve of a polypropylene material over almost seven decades. For that, both the new NETZSCH Kinexus rotational rheometer and the NETZSCH Rosand capillary rheometer are used.
Please visit our website for further information about our wide rheology product portfolio: Rheometers - NETZSCH Analyzing & Testing