Multi-Regional Natural Aging Behaviors and Degradation Mechanisms of Polyurethane-Coated Fabrics Under Coupled Multiple Environmental Factors

Polyurethane-coated fabrics are widely employed as tarpaulin materials. However, due to the long duration and large space requirements of natural exposure tests, studies on fabric degradation remain scarce. To systematically investigate the natural aging patterns and mechanisms of polyurethane-coated fabrics, this study conducted 24-month natural aging tests in three representative regions: Xishuangbanna (tropical monsoon climate), Xiamen (subtropical maritime monsoon climate), and Jinan (temperate monsoon climate). Changes in appearance, mechanical properties, surface morphology, elemental composition, and microstructure were thoroughly analyzed. The results indicated that gloss decreased by over 60%, the color difference exceeded 5.8, and tear strength was reduced by more than 50%. SEM, ATR-FTIR, and XPS analyses revealed that hydrolysis and oxidation occurred in the coating, leading to coating thinning, fiber exposure, and even damage. In Xishuangbanna, high temperature, high humidity, and strong solar radiation are responsible for the most severe degradation of fabrics. High temperature, humidity, and salt fog synergistically accelerated the aging process. In Jinan, significant thermal strain contributed to deterioration, and fabrics exhibited the mildest degradation. This multi-region natural exposure study realistically simulates in-service aging behavior, providing important validation for accelerated laboratory aging methods, product reliability improvement, and service-life modeling.