Modelling of capillary rheometer data and extrapolation of the viscosity function into the linear viscoelastic region

3- and 4 parameter models (Carreau-Winter, Sabia, Yasuda) are used for fitt ing capillary rheometer tests. These fitted data are then compared with rot ational viscosimeter test data in the region of small deformation speeds. T he results clearly demonstrate that the extrapolated capillary rheometer da ta acc. to the Sabia and Yasuda models yield good practice-relevant results . A good correlation was achieved between the calculated "zero viscosity" a nd the mean molecular mass and between the model curvature parameters and t he width of the molecular mass distribution. For quality assurance in labor atory rheometery and on-line rheometry these obtained good results are of h igh importance.