High-Speed-Extrusion amorpher Polymere am Beispiel von Polycarbonat (PC) und Polymethylmethacrylat (PMMA)

Increasing the efficiency of extrusion lines in plastics processing has been an important research topic for many years. This dissertation analyses the possibilities of processing amorphous thermoplastics at high speeds to increase throughput. The evaluations of the test series of a pilot plant show important influencing parameters as well as recommendations for the extrusion of these polymer types. In addition to adaptation to the screw geometry, the barrel properties and the external thermal control of the extruder, the flow behavior of the polymer was analyzed in more detail. Of particular interest for this type of processing is the structurally viscous behavior of polymer melt, which can be adjusted to the requirements of high-speed extrusion by using material mixtures. This method makes it possible to extrude a polycarbonate that is not suitable for high speeds on a high-speed extruder with correspondingly high throughputs. In addition to the experimental investigations, models were developed for the performance calculation of an extruder, the stress analysis of the extruder screw and the scaling of degassing zones on different line sizes. These models can generally be used for the design of single-screw extruders. In addition, a study on the strength behaviour of screw steels at room temperature or at operating temperature is presented on a testing plant for torsion.