OPTIMIZED DATA-COLLECTION FOR DETERMINATION OF THE MWD FROM THE VISCOSITY DATA OF POLYMER MELTS

Numerical differentiation is one source of loss of resolution in the d ifferential transformation of viscosity to MWD. Resolution can be impr oved by increasing the amount of viscosity data, keeping in mind that optimizing this process is necessary for practical reasons. This probl em was approached by finding the minimum point density and coverage re quired to resolve bimodality. For given point density and range, the h igher the superposition between the viscosity data and the ''knee'' in the viscosity function produced by each mode, the better the resoluti on. Testing time can be reduced and resolution can still be preserved by placing more points in the ''knee'' region in the viscosity functio n and by skipping the unnecessary points at low shear rates.