Objective With the development of the offshore photovoltaic (PV) industry and the large-scale construction of floating PV power stations, the environmental durability of marine buoys, which serve as the load-bearing structures of floating photovoltaic systems, directly affects the long-term stability and operational safety of offshore platforms. During service, buoy materials are exposed to significant degradation risks caused by multiple marine environmental factors, including high temperature, high salinity, intense ultraviolet (UV) radiation, and wave loading. To address the insufficient durability evaluation of floating buoy materials for offshore PV systems under complex marine conditions, high-density polyethylene (HDPE) was selected as the representative floating body material for weathering performance investigation, with the aim of providing a basis for material selection, lifetime assessment, and the development of relevant standards for offshore floating PV systems.

Method Considering the main influencing factors in marine service environments, including temperature, humidity, salinity, UV radiation and external loading, a weathering evaluation framework was established by combining single-factor tests, including UV radiation, hygrothermal exposure, and seawater immersion, with multi-factor coupled tests, including thermo-mechanical, hygrothermal-UV, and hygrothermal-UV-salt aging.

Result The results show that the HDPE material exhibits excellent performance under single-factor environments such as UV radiation and seawater immersion. Under multi-factor coupled conditions, it also demonstrates good environmental adaptability and weathering stability, indicating its ability to satisfy the long-term service performance requirements of buoy materials used in offshore floating PV systems.

Conclusion The established weathering evaluation method based on single-factor and multi-factor coupled conditions can more comprehensively reflect the aging behavior and performance retention characteristics of HDPE materials in complex marine environments. The results provide a technical basis for the structural design of offshore floating photovoltaic platforms.