Stability and Rheological Characteristics of <scp>UHMWPE</scp>/Paraffin Oil Thermo‐Reversible Sols, Obtained via Twin Screw Extrusion

ABSTRACT In this study, we produced UH‐PO sols using twin screw extrusion and characterized their thermal and rheological properties to evaluate changes induced by composition variation and extrusion process parameters. Extruder screw configuration, temperature profile, and UHMWPE mass fraction were varied, and the influence of N 2 inert gas purge during processing was also assessed. Rheological measurements using parallel plate rheology served as a diagnostic tool to study the sol‐state viscoelastic behavior and to identify thermal‐mechanical and oxidative degradation, evident through changes in UHMWPE molar mass. Thermogravimetric analysis was employed to examine the extrudates' composition and solvent evaporation dynamics. The trials demonstrated the feasibility of increasing polymer concentration while maintaining proper sol and gel formation. Additionally, N 2 gas tests highlighted that degradation of UH‐PO sols is predominantly oxygen‐driven, with inert gas purge showing significant protective effects, particularly at elevated temperatures. These findings underscore the potential of tuning process parameters to improve UHMWPE material properties while promoting cost efficiency and sustainability.