Mechanical and Rheological Behavior of High-Density Polyethylene under the Reversible Crosslinking Method and Comparison to a Conventional Method
Received: 21 August 2025 | Revised: 25 September 2025, 15 October 2025, and 7 November 2025 | Accepted: 9 November 2025 | Online: 12 January 2026
Corresponding author: Riadh Nemri
Abstract
This study investigates a Reversible Crosslinking (RXR) technique that enables the melt-state crosslinking of High-Density Polyethylene (HDPE). Reactive extrusion was carried out using a Brabender mixer, after which the RXR-crosslinked HDPE was ground in the solid state and subsequently reprocessed by compression molding. Dynamic Rheological Analysis (DRA) was employed to evaluate the crosslinking efficiency and viscosity variation through torque time curves. The Melt Flow Index (MFI) and gel content measurements were correlated with the DRA results after the second processing cycle. Differential Scanning Calorimetry (DSC), Wide-Angle X-ray Scattering (WAXS), Fourier-Transform Infrared Spectroscopy (FTIR), and mechanical measurements were conducted after the second compression molding. The RXR methodology provided a tunable rheological response, offering clear advantages in processing versatility and industrial optimization. FTIR confirmed the formation of new interchain C–S bonds, demonstrating effective bridging between HDPE main chains. WAXS and DSC revealed a slight reduction in crystallinity, whereas Thermogravimetric Analysis (TGA) indicated enhanced thermal stability in the early stages of decomposition. Mechanical tests showed a strong correlation between the crosslinking degree and crystallinity with both Young’s modulus and impact strength, suggesting that higher structural organization improves stiffness and impact resistance.
Keywords:
reactive extrusion, reversible crosslinking, TGA, microstructure, HDPEDownloads
References
H. Ahmad, E. Rostami-Tapeh-Esmaeil, and D. Rodrigue, "The effect of chemical crosslinking on the properties of Rotomolded high density polyethylene," Journal of Applied Polymer Science, vol. 141, no. 1, 2024, Art. no. e54744. DOI: https://doi.org/10.1002/app.54744
K. J. Kim and B. K. Kim, "Crosslinking of HDPE during reactive extrusion: Rheology, thermal, and mechanical properties," Journal of Applied Polymer Science, vol. 48, no. 6, pp. 981–986, 1993. DOI: https://doi.org/10.1002/app.1993.070480605
L. H. U. Andersson, B. Gustafsson, and T. Hjertberg, "Crosslinking of bimodal polyethylene," Polymer, vol. 45, no. 8, pp. 2577–2585, Apr. 2004. DOI: https://doi.org/10.1016/j.polymer.2004.01.073
Y. Ren et al., "Structures and impact strength variation of chemically crosslinked high-density polyethylene: effect of crosslinking density," RSC Advances, vol. 11, no. 12, pp. 6791–6797, Feb. 2021. DOI: https://doi.org/10.1039/D0RA10365A
A. S. Alghamdi, "Synthesis and Mechanical Characterization of High Density Polyethylene/Graphene Nanocomposites," Engineering, Technology & Applied Science Research, vol. 8, no. 2, pp. 2814–2817, Apr. 2018. DOI: https://doi.org/10.48084/etasr.1961
M. C. Montoya-Ospina, H. Verhoogt, M. Ordner, X. Tan, and T. A. Osswald, "Effect of cross-linking on the mechanical properties, degree of crystallinity and thermal stability of polyethylene vitrimers," Polymer Engineering & Science, vol. 62, no. 12, pp. 4203–4213, 2022. DOI: https://doi.org/10.1002/pen.26178
H. A. Khonakdar, J. Morshedian, U. Wagenknecht, and S. H. Jafari, "An investigation of chemical crosslinking effect on properties of high-density polyethylene," Polymer, vol. 44, no. 15, pp. 4301–4309, July 2003. DOI: https://doi.org/10.1016/S0032-3861(03)00363-X
H. Wu, M. Liang, and C. Lu, "Non-isothermal crystallization kinetics of peroxide-crosslinked polyethylene: Effect of solid state mechanochemical milling," Thermochimica Acta, vol. 545, pp. 148–156, Oct. 2012. DOI: https://doi.org/10.1016/j.tca.2012.07.008
M. Nikolova and M. Mateev, "Influence of fillers on the deformation behaviour of crosslinked HDPE: Part II—Radiation crosslinking," Polymer Degradation and Stability, vol. 31, no. 2, pp. 203–210, Jan. 1991. DOI: https://doi.org/10.1016/0141-3910(91)90075-3
S. Magana, A. Zerroukhi, C. Jegat, and N. Mignard, "Thermally reversible crosslinked polyethylene using Diels–Alder reaction in molten state," Reactive and Functional Polymers, vol. 70, no. 7, pp. 442–448, July 2010. DOI: https://doi.org/10.1016/j.reactfunctpolym.2010.04.007
K. Sirisinha, M. Boonkongkaew, and S. Kositchaiyong, "The effect of silane carriers on silane grafting of high-density polyethylene and properties of crosslinked products," Polymer Testing, vol. 29, no. 8, pp. 958–965, Dec. 2010. DOI: https://doi.org/10.1016/j.polymertesting.2010.08.004
W. Lv, Y. El-Hebshi, B. Li, Y. Xia, R. Xu, and X. Chen, "Investigation of thermo-reversibility of polymer crosslinked by reversible covalent bonds through torque measurement," Polymer Testing, vol. 32, no. 2, pp. 353–358, Apr. 2013. DOI: https://doi.org/10.1016/j.polymertesting.2012.11.017
M. Selvin, S. Shah, H. J. Maria, S. Thomas, R. Tuladhar, and M. Jacob, "Review on Recycling of Cross-Linked Polyethylene," Industrial & Engineering Chemistry Research, vol. 63, no. 3, pp. 1200–1214, Jan. 2024. DOI: https://doi.org/10.1021/acs.iecr.3c02580
S. Liu, R. Zhang, C. Fu, T. Zheng, and P. Xue, "Changes in Heat Resistance and Mechanical Properties of Peroxide Cross-Linking HDPE: Effects of Compounding Cross-Linkers," Polymers, vol. 17, no. 4, Jan. 2025, Art. no. 535. DOI: https://doi.org/10.3390/polym17040535
L. Di et al., "Influence of Crosslink Density on Electrical Performance and Rheological Properties of Crosslinked Polyethylene," Polymers, vol. 16, no. 5, Jan. 2024, Art. no. 676. DOI: https://doi.org/10.3390/polym16050676
J. K. Mishra, Y.-W. Chang, B. C. Lee, and S. H. Ryu, "Mechanical properties and heat shrinkability of electron beam crosslinked polyethylene–octene copolymer," Radiation Physics and Chemistry, vol. 77, no. 5, pp. 675–679, May 2008. DOI: https://doi.org/10.1016/j.radphyschem.2007.12.004
A. Martínez-Romo, R. González-Mota, J. J. Soto-Bernal, and I. Rosales-Candelas, "Investigating the Degradability of HDPE, LDPE, PE-BIO, and PE-OXO Films under UV-B Radiation," Journal of Spectroscopy, vol. 2015, 2015, Art. no. 586514. DOI: https://doi.org/10.1155/2015/586514
C. Charalambous, M. Danikas, Y. Yin, N. Vordos, J. W. Nolan, and A. Mitropoulos, "Study of the Behavior of Water Droplets Under the Influence of a Uniform Electric Field on Conventional Polyethylene and on Crosslinked Polyethylene (XLPE) with MgO Nanoparticles Samples," Engineering, Technology & Applied Science Research, vol. 7, no. 1, pp. 1323–1328, Feb. 2017. DOI: https://doi.org/10.48084/etasr.813
S. Bouhelal, M. E. Cagiao, D. Benachour, and F. J. B. Calleja, "Structure modification of isotactic polypropylene through chemical crosslinking: Toughening mechanism," Journal of Applied Polymer Science, vol. 103, no. 5, pp. 2968–2976, 2007. DOI: https://doi.org/10.1002/app.25406
P. D. Dharmaratne, G. H. Galabada, S. N. Malkanthi, and R. U. Halwatura, "Waste Polyethylene Reinforced with Coconut Fibers for Sustainable Construction: A Mechanical and Physical Property Evaluation Study," Engineering, Technology & Applied Science Research, vol. 15, no. 5, pp. 28136–28143, Oct. 2025. DOI: https://doi.org/10.48084/etasr.12512
E. Tarani, I. Arvanitidis, D. Christofilos, D. N. Bikiaris, K. Chrissafis, and G. Vourlias, "Calculation of the degree of crystallinity of HDPE/GNPs nanocomposites by using various experimental techniques: a comparative study," Journal of Materials Science, vol. 58, no. 4, pp. 1621–1639, Jan. 2023. DOI: https://doi.org/10.1007/s10853-022-08125-4
H. Saci, S. Bouhelal, B. Bouzarafa, D. López, and M. Fernández-García, "Reversible crosslinked low density polyethylenes: structure and thermal properties," Journal of Polymer Research, vol. 23, no. 4, Mar. 2016, Art. no. 68. DOI: https://doi.org/10.1007/s10965-016-0965-x
M. Bengtsson, P. Gatenholm, and K. Oksman, "The effect of crosslinking on the properties of polyethylene/wood flour composites," Composites Science and Technology, vol. 65, no. 10, pp. 1468–1479, Aug. 2005. DOI: https://doi.org/10.1016/j.compscitech.2004.12.050
Downloads
How to Cite
License
Copyright (c) 2025 Riadh Nemri, Said Bouhelal, Eleftheria Roumeli, Konstantinos Chrissafis, Dimitrios Bikiaris, Lhadi Otmani
This work is licensed under a Creative Commons Attribution 4.0 International License.
Authors who publish with this journal agree to the following terms:
- Authors retain the copyright and grant the journal the right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) after its publication in ETASR with an acknowledgement of its initial publication in this journal.
