Figure 8. Excess attenuation and viscosity in the extrusion process. A series of samples was run through the extruder, beginning with polyethylene (10 min). A polystyrene (PS) sample with a melt flow index (MFI, g/10 min) of 1.2 was extruded for the next hour, followed by another PS sample, MFI = 9.0. To demonstrate the reproducibility of the measurements, another PS sample (MFI = 1.2) was extruded at the end of the run. The measurements were taken at 193 °C. Return to article