Wood Plastic Composites: determination and comparison of the specific energy consumption for WPC compounding methods based on two state-of-the-art formulations

Sonja Kahr

Research output: ThesisMaster's Thesis

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This work focuses on the economic and qualitative comparison of four compounding methods for Wood Plastic Compounds (WPC), using two state-of-the-art formulations. In detail a counter-rotating twin screw extruder (TSE), co-rotating TSE and one heating-cooling mixer concept were tested processing a Polypropylene (PP) 40/60 and a Polyvinylchloride (PVC) 50/50 formulation. The measurements were done with the software WarpNet using ring- and flap- converters for the current transformation. To analyze the qualitative aspects of the compounds bulk density-, flowability- and SEM- (Scanning electron microscope) tests were done. All tests were done with two output rates to ensure industrial relevant processing ranges. Differences between the two materials were detected. PP leads to higher specific energy consumptions and a higher degree of efficiency than PVC. The higher output rates result in a better workload of the main drive and consequently to lower, unwanted process losses. Regarding the thermal and mechanical losses, PVC shows higher values than PP. The co-rotating TSE and the heating-cooling mixer lead to difficulties in the process control. Focusing on PP, the counter-rotating TSE showed the most economic results, followed by the co-rotator and the heating-cooling mixer. For PVC, the heating-cooling mixer is the most economic technology followed by the counter-rotator. Regarding the quality, significant differences were detected for all defined quality standards. The highest value for bulk density and flowability shows the co-rotator followed by the counter-rotator and the heating-cooling mixer. The lowest moisture level with 1% ± 0,38% rH was achieved by the counter-rotator which was 1% lower than with the other two machines. The homogeneity was given for all compounds, whereas the co-rotator led to a high degree of fiber manipulation and a darkening of the material.
Translated title of the contributionErfassung und Vergleich des spezifischen Energieverbrauchs für gängige Compoundiermethoden von holzfasergefüllten Kunststoffen am Beispiel der zwei verbreitetsten Rezepturen
Original languageEnglish
Awarding Institution
  • Montanuniversität
  • Holzer, Clemens, Supervisor (internal)
  • Laske, Stephan, Co-Supervisor (internal)
Award date17 Dec 2010
Publication statusPublished - 2010

Bibliographical note

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  • wood plastic compounds
  • extrusion
  • energy balance
  • compounding

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