A review with 36 refs. covering techniques and equipment used to shear-extrude solid polymeric materials. the technique involves the application of normal and shear forces in combination with high pressure and suitable modifications of polymer temperature, viz., first preheating to plastify and to homogenize the polymer and subsequently cooling to bring the polymer below the solidification point. Two technical modifications are described, involving comminution of the polymer carried out either inside or outside of the extruder's plastifying system; modified extruder designs are shown. The technique enables homogeneous fine (particle size even <100 #mu#m) polymer powders to be preprared. Incompatible polymers, which phase-separate and cannot be processed by conventional melt extrusion, can be homogenized and comminuted (and thereby later recycled) in a continuous way and also copulverized to yield blends.
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