Deformation mechanism of high-density polyethylene/liquid paraffin films during stretching

In this study, the deformation mechanism of high-density polyethylene (HDPE)/liquid paraffin (LP) films is systematically investigated. The findings demonstrates that the structural changes are significantly influenced by the LP content. Pure HDPE displays a pronounced cavitation phenomenon, whereas HDPE/LP films deform without cavitation. The yielding mechanism observed in HDPE/LP films is related with the extension of molecular chains and rotation/shearing of the lamellae. At high strains, pure HDPE and LP content lower than 20 % form a fibril-like crystal structure. However, samples with LP content exceeding 40 % form a highly oriented and periodically arranged fibrillar crystal structure. Last but not least, distinctly different cross-section morphologies are observed after extraction for HDPE/LP films. When LP content is below 20 %, the films exhibit a non-porous morphology. When the LP content exceeds 40 %, a loose porous morphology is observed after extraction. These findings provide valuable insights into the structural evolution and deformation behavior of HDPE/LP films under mechanical stress.