| In this study, the shear viscosity of calcium carbonate filled polypropylene was determined in two ways. In the first case, samples of calcium carbonate filled polypropylene were prepared using a counter rotating intermeshing twin screw extruder equipped with a gear pump between the extruder and die. The compounded product was pelletized and evaluated using a standard imposed rate capillary rheometer. In the second case, the shear viscosities of the same formulations were determined directly from the gear pump assisted twin screw extrusion process by extruding through instrumented capillary dies. In both cases, end error corrections were performed. The results of this study indicate that the lab scale gear pump assisted twin screw extrusion process can be used to generate rheological data on filled thermoplastics and that the results are generally in good agreement with the data obtained from more conventional capillary rheometers. |
