Real time measurement and control of viscosity for extrusion processes using recycled materials

Nguyen, Bao Kha, McNally, Gerald and Clarke, Alan (2014) Real time measurement and control of viscosity for extrusion processes using recycled materials. Polymer Degradation and Stability, 102. pp. 212-221. ISSN 0141-3910

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Abstract

The aim of this paper is to develop a new generation of extruder control system for recycled materials which has ability to automatically maintain constant a polymer melt viscosity of mixed recycled polymers during extrusion, regardless of variations in the Melt Flow Index (MFI) of recycled mixed grade high density polyethylene (HDPE) feedstock. The variations in MFI are due to differences in the source of the recycled material used. The work describes how melt viscosity for specific extruder/die system is calculated in real time using the rheological properties of the materials, the pressure drop through the extruder die and the actual throughput measurements using a gravimetric loss-in-weight hopper feeder. A closed-loop controller is also developed to automatically regulate screw speed and barrel temperature profile to achieve constant viscosity and enable consistent processing of variable grade recycled HDPE materials. Such a system will improve processability of mixed MFI polymers may also reduce the risk of polymer melt degradation, reduce producing large volumes of scrap/waste and lead to improvement in product quality. The experimental results of real time viscosity measurement and control using a 38 mm single screw extruder with different recycled HDPEs with widely different MFIs are reported in this work.

Item Type: Article
Keywords: Viscosity, Real time control, Recycled polymers
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Subjects: T Technology
T Technology > TJ Mechanical engineering and machinery > TJ0212 Control engineering systems. Automatic machinery (General)
T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK0275 Electric standards and measurements
Depositing User: Bao Kha Nguyen
Date Deposited: 17 Jul 2017 07:15
Last Modified: 17 Jul 2017 07:15
URI: http://sro.sussex.ac.uk/id/eprint/69281
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