Dynamic shear rheometer and method for its use

摘要

An improvement in a rheometer (10) and a method for measuring rheological properties of a viscoelastic test specimen at different temperatures, at which different temperatures the viscoelastic properties exhibit a relatively wide difference, wherein the test specimen is placed between and is coupled with opposed plates, one of the opposed plates (42) is oscillated angularly relative the other of the opposed plates (40), and the angular displacement of one of the plates relative to the other of the plates and the torque associated with the relative angular displacement are measured within an optimum range of torque and angular displacement for determining the rheological properties, wherein a first contact area (64) on one of the opposed plates (42) is coupled with the test specimen when the test specimen is at one of the different temperatures, and a second contact area (66) on the one of the opposed plates (42) is coupled with the test specimen when the test specimen is at another of the different temperatures, the first contact area (64) being different from the second contact area (66) such that, by virtue of the difference between the first and second contact areas, the torque and the relative angular displacement measured at each of the one and the other of the different temperatures fall within the optimum range.