LCR7000 & RHEOSIGHTS P/N: 974194 |
Rev: A
|
ECO: 52468
www.dynisco.com
From lab to production,
providing a window into the process
-51-
A shear rate sweep is a test where variable speeds (mm/min) or shear rates
(sec
-1
) are applied to the polymer. In doing so we can assess the rheological behavior of the
material at various shear rates.
PVC, PP, PET Example Rate Sweep Data
Note the Newtonian-like character of the PET at 285
°
C. The PP shows some signs of
turning toward a constant viscosity at lower rates, but the PVC looks like a powerlaw fluid
(straight line) throughout the sweep.
Constant Stress vs. Constant Rate
Constant stress tests on degrading material tested in the non-Newtonian region have
viscosity vs. time curves, which fall faster than the corresponding viscosity vs. time data,
collected at constant rate.
5.
Shear Rate Sweep
6.
Shear Stress Sweep
