DETERMINATION OF EXTENSIONAL VISCOSITY OF POLYPROPYLENE MELT USING THE REHOTENS TEST

摘要

In this work, the extensional viscosity of the polypropylene (PP) melt was determined using the rheotens test. Three different extrusion velocities were employed and the extensional viscosities were calculated following a "Newtonian local approach". A new test mode, the "steady state rheotens test", was tentatively used. The results indicate that an obvious difference exists among the extensional viscosities obtained at different extrusion velocities from the standard rheotens test. An overlapping of the extensional viscosity curves appeared at low two extrusion velocities in the steady state rheotens test. This indicates that, compared with the standard rheotens test, the steady state test is more accurate in determining the extensional viscosity of polymer melt.