Title: Representation of polymer mixing status during extrusion based on the model of ultrasonic reflection at screw

Authors: Youxing Chen; Haijun Xi; Ya Li; Zhaoba Wang

Addresses: National Key Laboratory for Electronic Measurement Technology, North University of China, Taiyuan, China ' Liaoning Qingyang Specialty Chemical Co., Ltd., Liaoyang City, Liaoning Province, China ' National Key Laboratory for Electronic Measurement Technology, North University of China, Taiyuan, China ' National Key Laboratory for Electronic Measurement Technology, North University of China, Taiyuan, China

Abstract: In the process of ultrasonic in-line monitoring the polymer mixing status, the screw structure has significant impacts on the ultrasonic echoes. The standard deviation of normalised ultrasonic attenuation coefficient is got by using correction methods based on the model of ultrasonic reflection at screw, which can be used to determine the status of polymer compounding. The model of ultrasonic reflection at screw, which is composed of the model of screw structure and the model of reflection attenuation ratio coefficient, is established by using the ultrasonic propagation time and amplitude for monitoring the pure polymer. Then the model is used to remove the impacts of the screw structure during polymer extrusion. The normalised ultrasonic attenuation coefficient is regarded as the characteristic, to determine the polymer mixing status. The results show that this method is effective and stable for monitoring the inline mixing processes of LDPE/CaCO3 and LDPE/BaSO4 compounds in the single screw extruder.

Keywords: polymer mixing status; extrusion; modelling; ultrasonic attenuation coefficient; screw structure; in-line monitoring; ultrasonic monitoring; single screw extruders.

DOI: 10.1504/IJMPT.2015.072234

International Journal of Materials and Product Technology, 2015 Vol.51 No.3, pp.209 - 219

Received: 19 Jul 2014
Accepted: 03 Oct 2014

Published online: 06 Oct 2015 *

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