Structure and properties evolution of UV crosslinked ultra‐high molecular weight polyethylene fiber during processing

Abstract With the development of heat and creep‐resistant UHMWPE fiber via UV crosslinking, its structure‐properties evolution during processing needs attention. The structures of UHMWPE fiber in different forms, the pre‐oriented yarn (POY), the full stretch yarn (FDY) and UV crosslinked FDY (UVFDY), obtained from our pilot line were systematically studied with differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD), small‐angle X‐ray scattering (SAXS), and solid‐state 13 C NMR. Additionally, the heat and creep resistance of UVFDY were evaluated by the temperature at break ( T b ), glass transition temperature ( T g ), time at break ( t b ) for a given aging temperature, and creep elongation ( L c ). The results demonstrated that UVFDY possessed high gel content (89.0%), high crystallinity (84.2%), and high orientation (91.7%). These characteristics caused UVFDY not only with excellent mechanical properties but also process extraordinary heat and creep resistance, especially for its much higher T b (220 °C), T g (−75.7 °C) and t b (20 h) while lower L c (7.8%), comparing with FDY ( T b = 158 °C, T g = −86.8 °C, t b = 1.3 h and L c = 38.2%). This work provides insights into the structure‐properties relationship of UVFDY, which will aid in the development of UV crosslinked UHMWPE fiber with better heat and creep resistance.