Measurement of Temporary and Permanent Shear with the Instron Capillary Rheometer

The Instron Capillary Rheometer, with special extremely fine capillaries, has been used to measure the apparent viscosities of non-Newtonian polymer-thickened multigrade oils at temperatures from 100°F to 320°F and shear rates to 10⁶ sec^-1. The same apparatus can produce permanent shear under extreme conditions. Temporary shear data at 100°, 150°, 210°, 280° and 320°F are reported for eight commercial oils and five experimental oils formulated with different VI improvers in the same base oil. Permanent shear data are given for a larger set of oils.