Comparison of off-line, on-line and in-line measuring techniques used for determining the rheological characteristics of polyethylene composites with calcium carbonate

Abstract

The article has presented comparative tests of the rheological characteristics of lowdensity polyethylene (LDPE) with an addition of calcium carbonate (CaCO 3 ), containing 7, 14, 21 and 28 wt % of filler, respectively. The measurements were carried out by an off-line measuring technique (using a modified dead-weight plastometer), an on-line measuring technique (with a gear pump capillary rheometer) and an in-line measuring technique (with an extruder rheometer). The rheological parameters of the polymeric materials were determined based on the OstwalddeWaele powerlaw model at a temperature of 170 °C. The effect of calcium carbonate addition on the characteristic of operation of each of the employed instruments, the flow curves, the viscosity curves, and the values of power-law index (n) and consistency factor (K) have been determined.