On the measurement and modeling of viscosity of polymers at low temperatures

Viscosity was measured for three amorphous polymers, PS, PMMA and PC, down to temperatures well below those normally available. Measurements were made in the dynamic mode and the Cox-Merz rule was applied to obtain the shear viscosity versus shear rate data. The Carreau-Yasuda viscosity model with WLF-type temperature dependence was found to provide good fits to the measured data over a wide range of temperatures.