ABSTRACT
These investigators also determined the temperature dependence of the extensional viscosity of TUPAC A, and their measurements are plotted in Fig. 7.6 as a function of tensile stress [5[. It is seen that the shape of the extensional viscosity curve is not altered by changing the temperature. ln fact, all the data can be made to overlap by means of a vertical shift, demonstrating the validity of the time-temperature superposition principle; the temperature shift factors are identical to those obtained from shear data.
