Study on the Reinforcement and Antioxidant Protection of Paper Cultural Relics by Fullerenol/Hydroxypropyl Cellulose Composites

As one of the most widely used materials for paintings and archival records, paper has laid the foundation for the flourishing development of human civilization. However, during long-term storage, paper inevitably undergoes deterioration processes such as acid hydrolysis and oxidative degradation under the combined influence of intrinsic and extrinsic factors, resulting in yellowing and a decline in mechanical properties. Consequently, there is an urgent need to develop comprehensive conservation materials that integrate both reinforcement and antioxidant functions. In this work, fullerenol (FOL) was introduced into the field of paper cultural relic conservation as an efficient radical scavenger and ultraviolet (UV) shielding component. It was compounded with hydroxypropyl cellulose (HPC), which possesses excellent film-forming ability and fiber affinity, to construct an FOL/HPC (FH) composite protective system. This system addressed the limitations of single-component protective materials, namely restricted functionality and insufficient durability. Experimental screening and optimization demonstrated that the formulation comprising 0.067 g/L FOL and 6.0 g/L HPC (denoted FH4) exhibited the best overall performance. FH4 treatment not only further enhanced the mechanical properties of the paper but also demonstrated superior protective efficacy under accelerated aging conditions. The incorporation of FOL effectively shielded UV radiation and scavenged reactive oxygen species (ROS) generated during cellulose degradation, thereby blocking the photo-oxidative chain reaction at its source. When applied to acidified old newspapers, the system likewise delivered excellent protective performance, validating its applicability and compatibility across different substrates. Furthermore, the synergistic mechanism of the FH composite system was elucidated by combining experimental characterizations with theoretical calculations. This study provides both experimental and theoretical foundations for the expanded application of fullerenol in paper cultural relic conservation and offers new insights into the development of multifunctional, long-lasting, and safe preventive conservation materials for paper-based cultural heritage.