Low frequency/shear rate measurements on polymer melts with a novel rheometer

To obtain the time dependent viscosity function over a wide experimental window, data from two different measuring instruments and methods were combined. The instruments involved were a conventional dynamic rheometer and the magnetoviscometer (MVM), a novel apparatus specially designed for measuring at low shear rates. For most of the investigated materials the MVM-data allow an expansion of the known time-range to higher values, thus giving additional information about the longest relaxation times in the systems, which in turn correspond to the high-molecular tail of the molar mass distribution. Especially in the long time range where it is difficult to get good dynamical data the experimental error of the MVM-data is very small.