Effect on the deacidification performance of paper by the synergism of fluorocarbon solvents

By blending multiple solvents, a deacidification solution that balances cost and performance can be achieved. However, the high inertness of fluorinated organic solvents acts as a double-edged sword—while preventing fiber degradation, it also hinders researchers from making improvements. In this study, a deacidification suspension with synergistic intermolecular interactions was prepared using nano-magnesium oxide (3 g/L) as the deacidifying agent and two cost-effective fluorocarbon solvents, perfluorobutyl methyl ether (PFM) and perfluorohexanone (PFH). The dispersion stability of nano-MgO in these solvents was investigated by comparing them with the Bookkeeper deacidification solution. The pH, alkaline reserve, and tensile strength of paper were measured before and after deacidification, as well as before and after dry-heat aging. The effects of solvents on different ink compositions and color changes were examined, and the mechanism of solvent synergy was analyzed through molecular electrostatic potential surface calculations. Additionally, scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FTIR) were employed to evaluate the effects of deacidification on paper properties. The results demonstrated that the deacidification solution prepared with the mixed PFM and PFH solvents significantly improved the dispersion of nano-MgO, enhanced its penetration depth into the paper cross-section, and achieved a more uniform surface distribution, all without compromising the paper's physical and chemical properties. The stability of the deacidification solution was maintained for up to 4 h, and when the PFH content reached 75 %, the deacidified paper exhibited a maximum pH of 8.21 and an alkaline reserve of 0.709 mol/kg, with only a 2 % change in tensile strength compared to untreated paper. After dry-heat aging, the reductions in pH, alkaline reserve, and tensile strength were all below 17 %.