Analysing the Relationship between Mechanical Properties and Inner Structure of LLDPE Virgin Film for Optimizing Extrusion Condition

In this study, we investigated the mechanical properties and inner structure of the films of linear low-density polyethylene (LLDPE) It was re-pelletized by a twin-screw extruder equipped with and without a molten-resin reservoir (MRR) with different extrusion conditions. The thin sample films (thickness: 0.1 mm) were prepared by a compression moulding machine and then their mechanical properties and inner structure were analysed by a tensile test machine and XRD, Imaging FT-IR, AFM and RAMAN analyses. From the tensile results, the mechanical properties of re-pelletized pellet films were improved compared to the film made from virgin LLDPE pellets. Besides, from the analysis results, some inner-structural changes were confirmed in films made from re-pelletized pellets by AFM and Raman analyses and they depend on the re-pelletizing process. Our results suggest that the re-pelletizing treatment affected the inner structure of the films, resulting in the improving their mechanical properties.