Deacidification plays an important role in the conservation of paper-based cultural heritage objects. Herein, a novel approach for the conservation of scale paper-based cultural heritage objects is proposed using a mixture of argon and ethylene oxide (EO-Ar) for the first time. The optimum process conditions for deacidification of ethylene oxide and argon mixture system are determined by orthogonal testing. To evaluate the stabilization effect of paper treated with EO-Ar, the degradation of the mechanical properties (tensile strength, folding endurance and tearing strength tests) of paper after artificial aging was evaluated. The results show that the treated paper had better durability with respect to tensile strength, folding endurance and tearing strength. Additionally, thermal stability, crystallinity and fiber wall thickness increased after EO-Ar treated, which was determined by scanning electron microscope (SEM), diffraction of X-rays (XRD), and thermo gravimetric (TG) analysis. Some compounds, such as polyethylene glycol, organic acids, esters, were detected by GC-MS after treatment with EO-Ar. Two hundred and forty books including acidic, weak acidic and alkaline books were successfully deacidified, resulting in pH values of paper ranges suitable for paper preservation. Finally, a possible mechanism of deacidification of EO-Ar was proposed.

The scroll paintings for ancestor trees have been used to inherit the spirit of ancestor worship as a historical record of family development since the late Ming Dynasty in China. A severely degraded scroll painting of an ancestor tree (made of cotton textiles) needs intervention and conservation treatment to mitigate further deterioration. On the basis of the previously reported characterization results for the painting, in this paper, a suspension that is composed of 0.6% cellulose nanofibril (CNF) and nanosized 0.15% MgO in aqueous solvent (denoted as the CNF-MgO susairpension) was prepared. Conventional characterization methods were used to assess the properties of model samples before and after treatment with the CNF-MgO suspension, as well as before and after degradation under two sets of conditions. The results show that the treated model samples are slightly alkaline, given the deposit of alkaline particles, and demonstrate good mechanical properties before and after degradation due to the increase in fiber-to-fiber bond and mitigation of acid-catalyzed hydrolysis. In spite of the non-transparency of CNF and MgO nanoparticles, they have little impact on the optical properties of textiles, as verified by transmittance data and the determination of color changes. This suspension was then used to reinforce and restore the scroll painting in a practical conservation process. The application of CNF and MgO nanoparticles on textile objects investigated in this study would expand our understanding of the conservation of such objects, especially for those that have already become acidic and degraded.