ELONGATIONAL TESTING

ELONGATIONAL TESTING Elongational Rheometer for Polymer Melts It is well known that the elongational flow behavior which dominates many processing techniques can not be determined from shear experiments. The patented RHEOTENS melt elongation testing technique has proven to be highly reproducible and sensitive and will differentiate even polymer melts showing small differences in molecular structure which can not be detected with analytical methods. The RHEOTENS 71.97 offers the following new features: Tandem pulley system Patented) An additional pair of pull-off wheels have been integrated to...

From a technological trial on extension to the function of the extensional viscosity In the technical elongation diagram the maximum draw-off speed (v) is a relative measurement for the „elongation" of the melt, while the maximum force (F) is a relative value for the melt strength. The RHEOTENS test is a rather complicated function of the characteristics of the polymer, dimensions of the capillary, length of the spin line and of the extrusion history. F=F (Polymer, Geometry, Process conditions) In the first step approach, invariance with respect to different mass flow rates can be found. This...

ELONGATIONAL TESTING „RHEOTENS curves allow you to differentiate between the smallest differences in the behavior of your batches, otherwise not detectable with shear The material producer has found that sample B has a wider molecular distribution (MW/Mn = 11.1), versus sample E (MW/Mn = 10). Sample B and E were run three times (with the respective curves lying on top of each other). The RHEOTENS curves (picture left) show significant changes in the melt strength between the two batches. This information could not have been gathered by looking at the viscosity curves (picture right). Function...