The intrinsic viscosity η (short: IV), also called Staudinger’s index, describes the structural and rheological properties of highly concentrated solutions and polymer melts in cm³/g. It is used to characterize the average molecular weight of PET and PA-based polymers.

The determination of the intrinsic viscosity (IV) is possible with all GÖTTFERT melt indexers via a correlation. This correlation is determined from a data set of measured melt indexes and measured intrinsic viscosity (IV), representative for the product-spectrum. Once established, the correlation is used by the melt indexer to calculate the intrinsic viscosity (IV) directly from the measured MFR/MVR. Both values are displayed and stored as result.

This makes it possible to determine the intrinsic viscosity together with the MFR/MVR quickly and easily in one test without the use of solvents.