Effect of accelerated ageing on flax reinforced high-density polyethylene composites

Flax fibers are gaining popularity as promising sustainable materials for production of green composites; however, its durability under prolonged environmental exposure remains a challenge for real-world structural applications. This study explores the effects of accelerated ageing on mechanical and microstructural behavior of flax reinforced high-density polyethylene (HDPE) composites exposed to ultraviolet radiation (UV), moisture and temperature for periods up to 1000 h. Material degradation was evaluated through tensile tests; Fourier transform electron microscopy (FTIR) and scanning electron microscopy (SEM). Tensile tests showed a reduction in failure strain and strength by 56% and 48% respectively, while increase in modulus by 27% after 1000 h. SEM revealed surface roughness and degradation of flax fibers, indicating weakened fiber-matrix bonding. Thermo-mechanical observations further confirmed a progressive embrittlement of HDPE because of ageing.