LOW FREQUENCY SHEAR RATE MEASUREMENTS ON POLYMER MELTS WITH A NOVEL RHEOMETER/

To obtain the time dependent viscosity function over a wide experiment al window, data from two different measuring instruments and methods w ere combined. The instruments involved were a conventional dynamic rhe ometer and the magnetoviscometer (MVM), a novel apparatus specially de signed for measuring at low shear rates. For most of the investigated materials the MVM-data allow an expansion of the known time-range to h igher values, thus giving additional information about the longest rel axation times in the systems, which in turn correspond to the high-mol ecular tail of the molar mass distribution. Especially in the long tim e range where it is difficult to get good dynamical data the experimen tal error of the MVM-data is very small.