Mixing and Compounding of Graphene/High Density Polyethylene Nanocomposites Using Twin‐Screw and Octa‐Screw Extrusions: A Comparative Study

Multi‐screw extrusions are crucial for compounding polymeric nanocomposites. However, achieving homogeneous nanomaterial dispersion in high‐viscosity matrices without severe thermal degradation remains a significant challenge. This study presents a comparative investigation evaluating the compounding efficacy of conventional twin‐screw extruders (TSE) against a uniquely designed octa‐screw extruder (OSE) for graphene‐filled high‐density polyethylene (HDPE) nanocomposites. The structural, thermal, flow, and mechanical properties of 5.0 wt% graphene/HDPE nanocomposites were systematically assessed. Morphological results indicate that the OSE's unique multi‐stage intermeshing geometry yields a significantly more uniform graphene dispersion and effectively reduces agglomeration compared to the TSE. Benefiting from a narrower residence time distribution and lower processing temperature profile, the OSE minimized thermal degradation while allowing highly exfoliated graphene to act as nanoscale solid lubricants. Consequently, OSE‐compounded nanocomposites exhibited superior macroscopic properties over TSE counterparts, including enhanced crystallinity (63.3% vs. 62.1%), improved ultimate tensile strength (28.5 MPa vs. 27.5 MPa), higher decomposition temperature (461°C vs. 457°C), and better melt flowability. These findings demonstrate that octa‐screw extrusion provides a scalable processing advantage for developing advanced, high‐performance polymer nanocomposites.