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Recycling of thermoplastic materials: Development of a self-adaptive process to the recycled materials
FARAH Elena, EL HAJJ SLEIMAN Ghinwa, LE GAL LA SALLE Eric, BAILLEUL Jean-Luc
download PDFAbstract. Over the last few decades, thermoplastic polymers have become increasingly popular and widely used materials in our lives. However, these mass consumptions remain difficult to reuse. Although mechanical recycling is being seriously proposed as an alternative solution [1], until now many obstacles prevent its application to polymers. Undetermined initial properties and aging conditions of post-consumer waste, which are, in fact, extremely variable, result in an ignorance of the aged material rheological properties before their reprocessing. As a consequence, the adjustment of extrusion parameters becomes very difficult and can vary over time and between supply batches. In this context, the project RECYPLAST-DEMO was proposed aiming at developing a prototype able to characterize, in real-time [2], the rheological properties of extruded waste materials and self-adjust the operating parameters of the machine, with the help of artificial intelligence, to maintain products of required quality. Our work concerns inline rheological characterization of materials using an instrumented die numerically tested with the software POLYFLOW® for the viscosity range of a PP, designed and experimentally validated in a later step of the project. The goal is to obtain the rheological behavior of the material from pressure difference measurements along the length of the developed die and assess data compared to rheological characterization measurements performed in laboratory on virgin material and aged ones. This paper highlights the effect of the processing temperature and the residence time on the aging of the polymer. Moreover, the numerical work of the developed extrusion die is presented and explained.
Keywords
Mechanical Recycling, Aging, Thermoplastics, Rheology, Inline Measurements
Published online 4/24/2024, 10 pages
Copyright © 2024 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: FARAH Elena, EL HAJJ SLEIMAN Ghinwa, LE GAL LA SALLE Eric, BAILLEUL Jean-Luc, Recycling of thermoplastic materials: Development of a self-adaptive process to the recycled materials, Materials Research Proceedings, Vol. 41, pp 2638-2647, 2024
DOI: https://doi.org/10.21741/9781644903131-289
The article was published as article 289 of the book Material Forming
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
References
[1] A. Tominaga, H. Sekiguchi, R. Nakano, S. Yao, and E. Takatori, “Advanced recycling process for waste plastics based on physical degradation theory and its stability,” J Mater Cycles Waste Manag, vol. 21, 2019. https://doi.org/https://doi.org/10.1007/s10163-018-0777-7
[2] J. A. Covas, “MONITORING OF POLYMER EXTRUSION AND COMPOUNDING PROCESSES,” 2020.
[3] European Comission, “The European Green Deal: COM(2019) 640 Final,” European Commission: Brussels, Belgium 2019.
[4] European Comission, “A New Circular Economy Action Plan for a Cleaner and More Competitive Europe: COM(2020) 98 Final,” European Commission: Brussels, Belgium 2020.
[5] P. Main et al., “Impact of Multiple Reprocessing on Properties of Polyhydroxybutyrate and Polypropylene,” Polymers, vol. 15, no. 20, p. 4126, Oct. 2023. https://doi.org/10.3390/polym15204126
[6] P. Phanthong, Y. Miyoshi, and S. Yao, “Development of Tensile Properties and Crystalline Conformation of Recycled Polypropylene by Re-Extrusion Using a Twin-Screw Extruder with an Additional Molten Resin Reservoir Unit,” Applied Sciences, vol. 11, no. 4, p. 1707, Feb. 2021. https://doi.org/10.3390/app11041707
[7] S. Aid, “Etude de la miscibilité des polymères par la méthode de coalescence des grains en vue du recyclage des DEEE par rotomoulage”.
[8] V. Massardier, “Le recyclage des mélanges de polymères thermoplastiques. Aspects thermodynamiques, chimiques et applications industrielles,” Comptes Rendus Chimie, vol. 5, no. 6–7, pp. 507–512, Jun. 2002. https://doi.org/10.1016/S1631-0748(02)01412-1
[9] S. Hermanová, J. Tocháček, J. Jančář, and J. Kalfus, “Effect of multiple extrusion on molecular structure of polypropylene impact copolymer,” Polymer Degradation and Stability, vol. 94, no. 10, pp. 1722–1727, Oct. 2009. https://doi.org/10.1016/j.polymdegradstab.2009.06.016
[10] M. Alotaibi, T. Aldhafeeri, and C. Barry, “The Impact of Reprocessing with a Quad Screw Extruder on the Degradation of Polypropylene,” Polymers, vol. 14, no. 13, p. 2661, Jun. 2022. https://doi.org/10.3390/polym14132661
[11] J. Tochacek and J. Jancar, “Processing degradation index (PDI) – A quantitative measure of processing stability of polypropylene,” Polymer Testing, vol. 31, no. 8, pp. 1115–1120, Dec. 2012. https://doi.org/10.1016/j.polymertesting.2012.08.004
[12] J. Tocháček, J. Jančář, J. Kalfus, and S. Hermanová, “Processing stability of polypropylene impact-copolymer during multiple extrusion – Effect of polymerization technology,” Polymer Degradation and Stability, vol. 96, no. 4, pp. 491–498, Apr. 2011. https://doi.org/10.1016/j.polymdegradstab.2011.01.018
[13] M. Padmanabhan and M. Bhattacharya, “Effect of extrusion processing history on the rheology of corn meal,” Journal of Food Engineering, vol. 18, no. 4, pp. 335–349, Jan. 1993. https://doi.org/10.1016/0260-8774(93)90051-K
[14] P. X. Li, O. H. Campanella, and A. K. Hardacre, “Using an In-Line Slit-Die Viscometer to Study the Effects of Extrusion Parameters on Corn Melt Rheology,” Cereal Chemistry Journal, vol. 81, no. 1, pp. 70–76, Jan. 2004. https://doi.org/10.1094/CCHEM.2004.81.1.70
[15] F. Robin et al., “Adjustable Twin-Slit Rheometer for Shear Viscosity Measurement of Extruded Complex Starchy Melts,” Chem. Eng. Technol., vol. 33, no. 10, pp. 1672–1678, Sep. 2010. https://doi.org/10.1002/ceat.201000151
[16] M. Horvat, M. Azad Emin, B. Hochstein, N. Willenbacher, and H. P. Schuchmann, “A multiple-step slit die rheometer for rheological characterization of extruded starch melts,” Journal of Food Engineering, vol. 116, no. 2, pp. 398–403, May 2013. https://doi.org/10.1016/j.jfoodeng.2012.11.028
[17] R. Rathner, W. Roland, H. Albrecht, F. Ruemer, and J. Miethlinger, “Applicability of the Cox-Merz Rule to High-Density Polyethylene Materials with Various Molecular Masses,” Polymers, vol. 13, no. 8, p. 1218, Apr. 2021. https://doi.org/10.3390/polym13081218
[18] S. Syrjälä and J. Aho, “Capillary rheometry of polymer melts — Simulation and experiment,” Korea-Aust. Rheol. J., vol. 24, no. 3, pp. 241–247, Sep. 2012. https://doi.org/10.1007/s13367-012-0029-7
