Effect of Ultraviolet Aging on the Structure and Wear Resistance of Ultra-high-Molecular-Weight Polyethylene Ropes

Ultra-high-molecular-weight polyethylene (UHMWPE) fiber ropes are widely used in towing, transportation, and outdoor rescue operation due to their exceptional strength and durability. However, prolonged exposure to ultraviolet (UV) light accelerates aging, significantly affecting their fiber structure and mechanical properties. To investigate the aging behavior of UHMWPE fiber ropes under ultraviolet light, their chemical composition, morphology, and strength of UHMWPE fiber ropes under ultraviolet light were analyzed using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy(FTIR), tensile test, and wear resistance experiments. The results indicate that ultraviolet light can break the main chain of ultra-high-molecular-weight polyethylene and induce the molecular degradation of polyethylene. Initially, the fiber surface is smooth, but progressive UV exposure causes the formation of cracks. Their mechanical properties deteriorate significantly, with tensile strength decreasing significantly from the original 1066 N to 265 N after six cycles of ultraviolet irradiation, representing a 75% strength loss. In addition, the wear resistance of UHMWPE ropes decreases with prolonged UV exposure. Ultraviolet radiation breaks the internal C–C bond, reducing the melting peak of folded chain crystallization. At elevated temperatures, irradiation facilitates the penetration of oxygen molecules and other gases through microcracks, leading to the formation of C=O bonds and initiating oxidation reactions. Ultimately, this results in the degradation of UHMWPE and a decrease in its mechanical properties.