Optimized data collection for determination of the MWD from the viscosity data of polymer melts

Abstract

Numerical differentiation is one source of loss of resolution in the differential transformation of viscosity to MWD. Resolution can be improved by increasing the amount of viscosity data, keeping in mind that optimizing this process is necessary for practical reasons. This problem was approached by finding the minimum point density and coverage required to resolve bimodality. For given point density and range, the higher the superposition between the viscosity data and the "knee" in the viscosity function produced by each mode, the better the resolution. Testing time can be reduced and resolution can still be preserved by placing more points in the "knee" region in the viscosity function and by skipping the unnecessary points at low shear rates.