Compounding of polyethylene composites using high speed twin and quad screw extruders

Abstract

The effect of high screw speed twin and quad screw extruders on mixing was investigated using polyethylene microcomposites with 1 wt% calcium carbonate. Using screws with similar designs extruder type influenced the effects that screw speeds of 300 to 200 rpm had on extruder residence time, melt temperature, drive torque, and head pressure. Parallel plate rheology indicated significant chain scission of the polymers, but better filler dispersion at screw speeds of 900 and 1500 rpm and better dispersion in the quad screw extruder. In the quad screw extruder, the lower melt temperatures and greater shear allowed better mixing at higher screw speeds than the twin screw extruder. The dispersion was confirmed with transmission electron microscopy.The effect of high screw speed twin and quad screw extruders on mixing was investigated using polyethylene microcomposites with 1 wt% calcium carbonate. Using screws with similar designs extruder type influenced the effects that screw speeds of 300 to 200 rpm had on extruder residence time, melt temperature, drive torque, and head pressure. Parallel plate rheology indicated significant chain scission of the polymers, but better filler dispersion at screw speeds of 900 and 1500 rpm and better dispersion in the quad screw extruder. In the quad screw extruder, the lower melt temperatures and greater shear allowed better mixing at higher screw speeds than the twin screw extruder. The dispersion was confirmed with transmission electron microscopy.