RHEOLOGICAL CHARACTERIZATION OF THE FLUID M1 AND OF ITS COMPONENTS

An opposing jet rheometer was used to measure the apparent elongational viscosity of fluid M1. The behaviour in simple shear was characterized by using different types of rotational rheometers. From the dynamic moduli in oscillatory shear the steady-state compliance and a characteristic relaxation time were calculated. The steady-state viscosity and the primary normal stress difference versus shear rate, as well as the temperature dependence of the zero shear viscosity, were measured. A study of flow instabilities becoming apparent above a critical shear stress was performed. The flow instabilities cause irreversible degradation. The molecular weight and the Mw/Mn ratio of the PIB component were deduced from measurements of the melt viscosity and the melt compliance, respectively. The relaxation time of the solvent could be evaluated both from oscillatory shear and normal stress measurements taking into account fluid inertia effects. © 1990.