Study on the Deacidification and Reinforcement of Paper Cultural Relics Using Polyethyleneimine-Grafted Carboxylated Nanocellulose

In this study, polyethyleneimine (PEI)-grafted carboxylated nanocellulose (CNC) was used for the deacidification, reinforcement, and protection of paper cultural relics. The optimal mass ratio of PEI to CNC during the synthesis process and the optimal aqueous solution concentration for protecting paper cultural relics after the reaction were investigated by evaluating indicators such as tensile strength and pH value. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and other techniques were employed to reveal the protective mechanism of PEI-modified CNC on paper cultural relics. The experimental results showed that when the mass ratio of PEI to CNC was 1:1 and the solution concentration was 1.5 wt%, the best deacidification and reinforcement protection effect on paper cultural relics was achieved. At this point, the pH value of the paper reached 7.6, representing a 97% increase, and the tensile strength increased to 1.22 N/mm, a 17% increase. In addition, the ability of PEI-g-CNC to chelate iron ions was successfully verified, providing a basis for protecting paper cultural relics containing metal ions.