The Effect of Materials’ Rheology on Process Energy Consumption and Melt Thermal Quality in Polymer Extrusion

Chamil Abeykoon, Paula Pérez, Adrian L. Kelly

Research output: Contribution to journalArticlepeer-review


Polymer extrusion is an important but an energy intensive method of processing polymeric materials. The rapid increase in demand of polymeric products has forced manufactures to rethink their processing efficiencies to manufacture good quality products with low-unit-cost. Here, analysing the operational conditions has become a key strategy to achieve both energy and thermal efficiencies simultaneously. This study aims to explore the effects of polymers’ rheology on the energy consumption and melt thermal quality (i.e., a thermally homogeneous melt flow in both radial and axil directions) of extruders. Six commodity grades of polymers (LDPE, LLDPE, PP, PET, PS and PMMA) were processed at different conditions in two types of continuous screw extruders. Total power, motor power, and melt temperature profiles were analysed in an industrial scale single-screw extruder. Moreover, the active power, mass throughput, torque, and power factor were measured in a laboratory scale twin-screw extruder. The results confirmed that the specific energy consumption for both single and twin screw extruders tends to decrease with the processing speed. However, this action deteriorates the thermal stability of the melt regardless the nature of the polymer. Rheological characterization results showed that the viscosity of LDPE and PS exhibited a normal shear thinning behaviour. However, PMMA presented a shear thickening behaviour at moderate-to-high shear rates, indicating the possible formation of entanglements. Overall, the findings of this work confirm that the materials’ rheology has an appreciable correlation with the energy consumption in polymer extrusion and also most of the findings are in agreement with the previously reported investigations. Therefore, further research should be useful for identifying possible correlations between key process parameters and hence to further understand the processing behaviour for wide range of machines, polymers and operating conditions.
Original languageEnglish
Pages (from-to)1244-1265
JournalPolymer Engineering and Science
Issue number6
Publication statusPublished - 11 Apr 2020


  • Polymer extrusion
  • Process monitoring
  • Specific energy consumption
  • Torque
  • Power factor
  • Polymer rheology
  • Thermal stability


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