Iran Polymer and Petrochemical Institute Polyolefins Journal 2322-2212 12 4 2025 12 01 Influence of heat treatment on the mechanical, thermal and thermophysical properties of low-density polyethylene 241 250 2127 10.22063/poj.2025.35741.1368 EN Derradji Dadache Faculty of Technology, Process Engineering Laboratory, University of Bordj Bou Arreridj, 34000 Algeria Farid Rouabah Laboratory of Physico-Chemistry of High Polymers, Institute of Materials science and Techniques, Setif 1 University Ferhat Abbas, Setif, 19000 Algeria 0009-0006-0081-0435 Zahir Rahem Laboratory of Multiphase Polymeric Materials, Institute of Materials science and Techniques, Setif 1 University Ferhat Abbas, Setif 19000, Algeria Journal Article 2025 07 27 This study demonstrates that quenching and annealing significantly influence the mechanical and thermophysical behavior of low density polyethylene (LDPE). Rapid quenching at temperature of –25 °C enhances ductility by increasing elongation at break, despite reducing thermophysical properties, likely due to microstructural refinement. In contrast, post-quenching annealing especially at 100 °C improves thermal conductivity and crystallinity but reduces ductility. The results underscore a tunable balance between thermal and mechanical performance, governed by the interplay of beta (β-) and alpha (α-) relaxation modes during heat treatment. Post-quenching annealing of low density polyethylene LDPE, particularly at 100 °C, significantly enhanced thermal conductivity, diffusivity, and crystallinity, albeit with a trade-off in ductility and increased brittleness. Quenching within the beta (β-) relaxation range promoted maximum ductility, while annealing in the alpha (α-) relaxation range improved thermophysical properties. These findings reveal that precise control of heat treatment conditions enables a tunable balance between mechanical flexibility and thermophysical performance in LDPE http://poj.ippi.ac.ir/article_2127_284d2111fe4cd918106c216cf69bc2d9.pdf