Expanding the industrial use of linear viscoelastic material functions

Polymer melts usually have relaxation times in a broad frequency range. To capture the full rheological behaviour, multiple rheometers are used. Due to the different modes of operation, combination of the data into a single rheological function often involves solving one or more inverse, ill-posed problems. Here, as an alternative approach, a new approximate direct analytical method is presented that allows the broadening of oscillatory shear data obtained from dynamic mechanical spectrometers, to low frequencies by using converted constant stress compliance data. The accuracy of the broadened curves depends on the experimental accuracy and the specific time scales of the polymer and the rheometers. The method is most effective when used in combination with inverse problem solvers. By doing so, translucence, insight, and directness from the analytic method is added to the potential accuracy of the full inverse problem solver