Ultrasonic Monitoring Technology for Polymer Compounding Extrusion

Abstract In order to optimize control of the extrusion process of polymer compounds in the screw extruder, it is necessary to monitor the compounding state in-line. Therefore a polyetheretherketone (PEEK) buffer rod with a cooling device is analyzed and designed. The ultrasound probe, whose performance is tested at high temperature, is composed of a newly developed PEEK buffer rod and ultrasonic transducer. Then the ultrasonic probe is applied for the in-line ultrasonic monitoring of polymer extrusion of low-density polyethylene (LDPE)/CaCO3 compounds and LDPE/BaSO4 compounds. The results show that the attenuation has a relation to the composition of the polymer compounds and filler concentration. The results also indicate that the presented ultrasonic technique may be used for determining the mixing status of polymer/filler systems with multi-probes at different locations inside the extruder barrel during the extrusion processes.