Accelerated Ageing of Unidirectional Flax Fibers Reinforced Recycled Polypropylene Composites

Authors: Lara Alam, Laetitia Van-Schoors, Olivier Sicot, Benoit Piezel, Shahram Aivazzadeh

Abstract:

Over the last decades, worldwide environmental awareness has grown due to the depletion of raw material resources and global warming. This awareness has prompted the development of new products more environmentally friendly. Among these products are biocomposite materials reinforced with natural fibers. The main challenge in developing the use of biocomposites in exterior applications is the lack of knowledge about their durability and the evolution of their mechanical and physicochemical properties in the long term. The aim of this work is to study the photooxidation of unidirectional (UD) composites based on recycled matrix. For this purpose, UD flax fiber composites based on recycled polypropylene were prepared by thermocompression. An accelerated aging test was carried out using a xenon arc WeatherOmeter. The consequences of UV exposure on the chemical composition and morphology of the surface of composites as well as on their tensile mechanical properties have been reported. The results showed that accelerated aging had a significant effect on the surface of these composites while it had little impact on their mechanical properties.

Keywords: Flax fiber, photooxidation, physico-chemical properties, recycled polypropylene, tensile properties.

References:

[1] C. Baley, A. Bourmaud, et P. Davies, « Eighty years of composites reinforced by flax fibres: A historical review », Composites Part A: Applied Science and Manufacturing, vol. 144, p. 106333, mai 2021, doi: 10.1016/j.compositesa.2021.106333.
[2] D. Mathijsen, « The renaissance of flax fibers », Reinforced Plastics, vol. 62, no 3, p. 138‑147, juin 2018, doi: 10.1016/j.repl.2017.11.020.
[3] C. Baley et A. Bourmaud, « Average tensile properties of French elementary flax fibers », Materials Letters, vol. 122, p. 159‑161, mai 2014, doi: 10.1016/j.matlet.2014.02.030.
[4] R. Seldén, B. Nyström, et R. Långström, « UV aging of poly(propylene)/wood-fiber composites: UV Aging of Poly(propylene)/Wood-Fiber Composites », Polym Compos, vol. 25, no 5, p. 543‑553, oct. 2004, doi: 10.1002/pc.20048.
[5] L. Soccalingame et al., « Reprocessing of artificial UV-weathered wood flour reinforced polypropylene composites », Polymer Degradation and Stability, vol. 120, p. 313‑327, oct. 2015, doi: 10.1016/j.polymdegradstab.2015.07.013.
[6] M. D. H. Beg et K. L. Pickering, « Accelerated weathering of unbleached and bleached Kraft wood fibre reinforced polypropylene composites », Polymer Degradation and Stability, vol. 93, no 10, p. 1939‑1946, oct. 2008, doi: 10.1016/j.polymdegradstab.2008.06.012.
[7] D. Scida et al., « Hygrothermal/UV Aging Effect on Visual Aspect and Mechanical Properties of Non-Woven Natural-Fiber Composites », Journal of Renewable Materials, vol. 7, no 9, p. 865‑875, 2019, doi: 10.32604/jrm.2019.06609.
[8] C. Homkhiew, T. Ratanawilai, et W. Thongruang, « Effects of natural weathering on the properties of recycled polypropylene composites reinforced with rubberwood flour », Industrial Crops and Products, vol. 56, p. 52‑59, mai 2014, doi: 10.1016/j.indcrop.2014.02.034.
[9] D. J. Carlsson et D. M. Wiles, « The Photooxidative Degradation of Polypropylene. Part I. Photooxidation and Photoinitiation Processes », Journal of Macromolecular Science, Part C: Polymer Reviews, vol. 14, no 1, p. 65‑106, janv. 1976, doi: 10.1080/15321797608076113.
[10] A. François-Heude, E. Richaud, E. Desnoux, et X. Colin, « A general kinetic model for the photothermal oxidation of polypropylene », Journal of Photochemistry and Photobiology A: Chemistry, vol. 296, p. 48‑65, janv. 2015, doi: 10.1016/j.jphotochem.2014.08.015.
[11] D. J. Carlsson, A. Garton, et D. M. Wiles, « Initiation of Polypropylene Photooxidation. 2. Potential Processes and Their Relevance to Stability », Macromolecules, vol. 9, no 5, p. 695‑701, sept. 1976, doi: 10.1021/ma60053a002.
[12] D. M. Philip, J. Attwood, D. A. Hulme, et D. P. Shipton, « Evaluation of Weathering in Mixed Polyethylene and Polypropylene Products », p. 113, mars 2004.
[13] M. S. Rabello et J. R. White, « Crystallization and melting behaviour of photodegraded polypropylene– 1. Chemi-crystallization », p. 9.
[14] A. Cogulet, P. Blanchet, et V. Landry, « Wood degradation under UV irradiation: A lignin characterization », Journal of Photochemistry and Photobiology B: Biology, vol. 158, p. 184‑191, mai 2016, doi: 10.1016/j.jphotobiol.2016.02.030.
[15] L. Soccalingame, D. Perrin, J.-C. Bénézet, et A. Bergeret, « Reprocessing of UV-weathered wood flour reinforced polypropylene composites: Study of a natural outdoor exposure », Polymer Degradation and Stability, vol. 133, p. 389‑398, nov. 2016, doi: 10.1016/j.polymdegradstab.2016.09.011.
[16] C. Badji, J. Beigbeder, H. Garay, A. Bergeret, J.-C. Bénézet, et V. Desauziers, « Exterior and under glass natural weathering of hemp fibers reinforced polypropylene biocomposites: Impact on mechanical, chemical, microstructural and visual aspect properties », Polymer Degradation and Stability, vol. 148, p. 104‑116, févr. 2018, doi: 10.1016/j.polymdegradstab.2017.12.015.
[17] Y. Peng, R. Liu, J. Cao, et Y. Chen, « Effects of UV weathering on surface properties of polypropylene composites reinforced with wood flour, lignin, and cellulose », Applied Surface Science, vol. 317, p. 385‑392, oct. 2014, doi: 10.1016/j.apsusc.2014.08.140.
[18] S. Ghahri, S. K. Najafi, B. Mohebby, et M. Tajvidi, « Impact strength improvement of wood flour-recycled polypropylene composites », J. Appl. Polym. Sci., vol. 124, no 2, p. 1074‑1080, avr. 2012, doi: 10.1002/app.34015.
[19] S. Butylina, M. Hyvärinen, et T. Kärki, « A study of surface changes of wood-polypropylene composites as the result of exterior weathering », Polymer Degradation and Stability, vol. 97, no 3, p. 337‑345, mars 2012, doi: 10.1016/j.polymdegradstab.2011.12.014.
[20] H. Du, W. Wang, Q. Wang, Z. Zhang, S. Sui, et Y. Zhang, « Effects of pigments on the UV degradation of wood-flour/HDPE composites », J. Appl. Polym. Sci., p. n/a-n/a, 2010, doi: 10.1002/app.32430.
[21] M. Hamzah et al., « Surface chemistry changes and microstructure evaluation of low density nanocluster polyethylene under natural weathering: A spectroscopic investigation », J. Phys.: Conf. Ser., vol. 984, p. 012010, mars 2018, doi: 10.1088/1742-6596/984/1/012010.
[22] Y. Lv et al., « Outdoor and accelerated laboratory weathering of polypropylene: A comparison and correlation study », Polymer Degradation and Stability, vol. 112, p. 145‑159, févr. 2015, doi: 10.1016/j.polymdegradstab.2014.12.023.
[23] S.-S. Choi, H.-S. Chung, Y.-T. Joo, B.-K. Min, et S.-H. Lee, « Analysis of the whitening phenomenon of a thermoplastic elastomer article by UV weathering », Polymer Testing, vol. 30, no 4, p. 415‑419, juin 2011, doi: 10.1016/j.polymertesting.2011.02.010.
[24] T. Cadu, L. Van Schoors, O. Sicot, S. Moscardelli, L. Divet, et S. Fontaine, « Cyclic hygrothermal ageing of flax fibers’ bundles and unidirectional flax/epoxy composite. Are bio-based reinforced composites so sensitive? », Industrial Crops and Products, vol. 141, p. 111730, déc. 2019, doi: 10.1016/j.indcrop.2019.111730.
[25] P. M. Giuliani, O. Giannini, et R. Panciroli, « Characterizing flax fiber reinforced bio-composites under monotonic and cyclic tensile loading », Composite Structures, vol. 280, p. 114803, janv. 2022, doi: 10.1016/j.compstruct.2021.114803.
[26] C. Baley et al., « Flax/PP manufacture by automated fibre placement (AFP) », Materials & Design, vol. 94, p. 207‑213, mars 2016, doi: 10.1016/j.matdes.2016.01.011.