IN-LINE ULTRASONIC MONITORING OF POLYMER BLENDING IN A TWIN-SCREW EXTRUDER

摘要

Polymer blending using a twin-screw extruder is a widely used process in polymer processing industry by which more than one polymers are blended under molten state to achieve properties that are not available with each of the individual polymer. In the current work, high temperature ultrasonic sensors have been installed at several locations on a twin-screw extruder to monitor the blending process at various locations along the polymer flow direction inside the mixing channel of the extruder and at the exit of the extruder. The polymer blends were composed of a high-density polyethylene (HDPE) and a polystyrene (PS). The experiments were carried out under different mixing intensities, feed rates, and PS concentrations. Samples were collected at ultrasonically probed locations and then compared with the ultrasonic measurement data. The study has revealed close relations between the ultrasonic data and the status of the polymer blends and demonstrated that the ultrasonic technology presented in this communication can be a valuable tool for providing in-process information about polymer blending processes.