The rheological properties of polymers in shear as well as in extensional flow are essential for their processing.
Unfortunately their complete characterisation in the laboratory requires the complementary use of sophisticated techniques which are time consuming and need great expertise. Therefore quality control is mainly limited to the measurement of a melt flow index, a shear viscosity and eventually a melt strength test to assess extensional properties. The on-line monitoring of material parameters would be very helpful but is today mostly restricted, whenever performed, to MFI or a capillary shear viscosity measurement.
The HAAKE X-die has been developed to cover the need for a quick characterisation in shear and extension, with little or even no operator intervention. It can be mounted on a traditional capillary rheometer or directly on-line with a melt pump feeding it. Data obtained by this die with a standard LDPE already tested in round robin tests, are presented and confirm the validity of this new approach.
A copy of this Laboratory Report is available by requesting LR-39