Reinforced protection of fragile bronze cultural relics based on nano-cuprammonium fiber material

Bronze artifacts often suffer from “bronze disease” due to the presence of chloride ions, which result from copper chlorides forming on their surfaces during storage. Therefore, reinforced protection is essential for these unearthed cultural artifacts, and new materials for the reinforced protection of fragile bronzes are urgently needed. In this study, cuprammonium solvent and nanocellulose (CNC) were utilized as reinforcement materials to protect fragile bronzes. The chemical and aesthetic properties before and after reinforcement were analyzed using ultra-depth field microscopes, SEM-EDX, XRD, and Raman spectroscopy. The results indicated that at a nano-cuprammonium reinforcer concentration of 2.5 mol/L, the optimal reinforcement effect on simulated bronze powdery rust samples was achieved.Mechanical strength increased by an average of 77.59%. The mass growth rate reached 84.8%, while the color difference \(\Delta E\) remained below 4.0. Additionally, aging resistance significantly improved, aligning with cultural artifact protection standards.Meanwhile, a compact and stable protective membrane formed on the surface of the bronzes, isolating the bronze matrix from direct contact with the external environment, which delayed bronze corrosion and contributed to long-term stable preservation.

Graphical Abstract