Obtaining the highest possible level of weathering resistance to protect the polymeric composites against sunlight and free radicals is the primary function of every exterior composite, such as polyurethane (PU). In this paper, a typical PU matrix was modified by two differently reduced graphene oxide nanosheets to enhance long-term weathering stability. The synthesized graphene oxide nanosheets were reduced by Nettle leaves extract as a green reductant and hydrazine as a typical reducing agent. The graphene oxide and two reduced species were embedded in PU to investigate their impact on weathering stability. Several techniques were employed to assess the weathering performance during 1400 h exposure to artificially accelerated conditions. Achieving superior weathering performance approved the effective role of reduced graphene oxide (especially green reduced) in elevating weathering stability of PU nanocomposites. The active mechanisms involved in such improvement were extensively discussed.

获得最高水平的耐候性以保护聚合物复合材料免受日光和自由基的侵蚀是每种外部复合材料（例如聚氨酯（PU））的主要功能。在本文中，典型的PU基质被两种不同还原度的氧化石墨烯纳米片改性，以增强长期耐候性。通过荨麻叶提取物作为绿色还原剂和肼作为典型的还原剂还原合成的氧化石墨烯纳米片。将氧化石墨烯和两种还原物种嵌入PU中，以研究它们对耐候性的影响。几种技术被用来评估在1400 h暴露于人工加速条件下的耐候性能。实现优异的耐候性能，证实了氧化石墨烯（特别是绿色还原）在提高PU纳米复合材料的耐候稳定性方面的有效作用。广泛讨论了涉及这种改进的积极机制。