Abstract: Polymeric materials are widely used in the petrochemical industry and infrastructure sector due to their excellent performance and low cost. However, under certain utilization conditions, these materials are prone to aging, manifesting as structural fracture and performance degradation, which consequently shortens their service life. This paper takes polyethylene as a representative example to review the oxidative degradation mechanisms of polymers, and analyzes how aging-induced changes, such as chain scission and crystallinity changes, affect the performance of PE. On this basis, the study further discusses major recycling pathways for polymers, with a focus on comparing the characteristics and challenges of PE recycling via physical processing, pyrolysis, hydrogenolysis, and oxidative degradation. These findings may provide theoretical support for the green development and circular utilization of polymers, and contribute to the sustainable advancement of the polymer industry.

Key words: aging of polymeric materials, polyethylene, oxidative degradation, polymer recycling, sustainable utilization