Croitoru Catalin, Roata Ionut Claudiu
Materials Engineering and Welding Department, Transilvania University of Brasov, Eroilor 29 Str., 500039 Brasov, Romania.
Molecules. 2024 Feb 22;29(5):963. doi: 10.3390/molecules29050963.
This research explores the potential of ionic liquids (ILs) in restoring paper artifacts, particularly an aged book sample. Three distinct ILs-1-ethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide, 1-methyl-3-pentylimidazolium bis(trifluoromethylsulfonyl)imide, and 1-methyl-3-heptylimidazolium bis(trifluoromethylsulfonyl)imide -both in their pure form and isopropanol mixtures, were examined for their specific consumption in conjunction with paper, with 1-ethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide displaying the highest absorption. Notably, the methyl-3-heptylimidazolium ionic liquid displayed pronounced deacidification capabilities, elevating the paper pH close to a neutral 7. The treated paper exhibited significant color enhancements, particularly with 1-heptyl-3-methylimidazolium and 1-pentyl-3-methylimidazolium ILs, as evidenced by CIE-Lab* parameters. An exploration of ILs as potential UV stabilizers for paper unveiled promising outcomes, with 1-heptyl-3-methylimidazolium IL demonstrating minimal yellowing post-UV irradiation. FTIR spectra elucidated structural alterations, underscoring the efficacy of ILs in removing small-molecular additives and macromolecules. The study also addressed the preservation of inked artifacts during cleaning, showcasing ILs' ability to solubilize iron gall ink, particularly the one with the 1-ethyl-3-propylimidazolium cation. While exercising caution for prolonged use on inked supports is still recommended, ILs are shown here to be valuable for cleaning ink-stained surfaces, establishing their effectiveness in paper restoration and cultural heritage preservation.
本研究探索了离子液体（ILs）在修复纸质文物，特别是一本陈旧书籍样本方面的潜力。研究了三种不同的离子液体——1-乙基-3-丙基咪唑双（三氟甲基磺酰）亚胺、1-甲基-3-戊基咪唑双（三氟甲基磺酰）亚胺和1-甲基-3-庚基咪唑双（三氟甲基磺酰）亚胺——它们的纯形式以及与异丙醇的混合物，结合纸张考察了它们的特定消耗量，其中1-乙基-3-丙基咪唑双（三氟甲基磺酰）亚胺的吸收量最高。值得注意的是，1-甲基-3-庚基咪唑离子液体显示出显著的脱酸能力，能将纸张pH值提升至接近中性的7。经处理的纸张在颜色上有显著增强，特别是使用1-庚基-3-甲基咪唑和1-戊基-3-甲基咪唑离子液体时，CIE-Lab*参数证明了这一点。对离子液体作为纸张潜在紫外线稳定剂的探索取得了有前景的成果，1-庚基-3-甲基咪唑离子液体在紫外线照射后变黄程度最小。傅里叶变换红外光谱（FTIR）阐明了结构变化，突出了离子液体在去除小分子添加剂和大分子方面的功效。该研究还探讨了在清洁过程中对有墨水痕迹文物的保护，展示了离子液体溶解铁胆墨水的能力，特别是含有1-乙基-3-丙基咪唑阳离子的墨水。虽然仍建议在有墨水痕迹的载体上长时间使用时要谨慎，但此处表明离子液体对于清洁有墨水污渍的表面很有价值，确立了它们在纸张修复和文化遗产保护方面的有效性。
