| Abstract: | A self‐made dynamic capillary rheometer (DCR) was designed to investigate the dynamic viscoelastic characteristic of polypropylene (PP) melt during the pulsatile pressure extrusion. A vibration force field was parallel superposed upon steady shear flow in this DCR by means of a vibration driven piston. During the pulsatile pressure extruding process in DCR, the PP melt displayed apparent viscoelasticity. The experiment results proved the pressure pulsatile extrusion could reduce the viscosity of polymer melts effectively. The phase difference between the shear stress and the shear rate decreased with the superposed vibration. But, at large amplitude conditions, the viscosity has an increasing tendency. This maybe illuminated that large amplitude could be harmful for the vibration‐assistant polymer processing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1834–1838, 2006 |
