Zhao Xing, Wang Liqin, Guo Lang, Ma Yanni, Wang Ziming, Niu Qing, Zheng Liping
Key Laboratory of Cultural Heritage Research and Conservation (Northwest University), Ministry of Education, Xi'an, People's Republic of China.
School of Cultural Heritage, Northwest University, Xi'an, People's Republic of China.
Sci Rep. 2020 Dec 10;10(1):21724. doi: 10.1038/s41598-020-78705-4.
In situ consolidation is the most common treatment to conserve cultural relics, but materials for preserving fragile organic cultural relics in humid archaeological excavation sites are scarce. To solve the problem, a moisture-curable polyurethane (MCPU) prepolymer was synthesized by reacting isophorone diisocyanate with polyethylene glycol 600. The standard acetone-dibutylamine method, Fourier transform infrared spectroscopy, gel chromatography and thermogravimetric analysis were utilized to determine the change in isocyanate groups before and after the reaction, the prepolymer molecular weight, the thermal decomposition kinetic parameters and the MCPU film lifetime. The results showed that the number-average molecular weight of the prepolymer was 749, and the weight average molecular weight was 1684. Isophorone groups in the prepolymer react with moisture in the air to form colorless, transparent, flexible films. The thermal decomposition of the MCPU films was a first-order reaction, and the decomposition process consisted of two stages. The Dakin equation was used to obtain the thermal aging equation lg t = 4600.82/T - 8.07, meaning that at 15 °C, the sample has an approximately 150-year lifetime. A new conservation material was developed, and its thermal decomposition kinetics were studied, which are significant for the conservation of fragile organic cultural relics in humid environments.
原位加固是文物保护中最常用的处理方法，但在潮湿考古发掘现场用于保护脆弱有机文物的材料却很稀缺。为解决这一问题，通过异佛尔酮二异氰酸酯与聚乙二醇600反应合成了一种湿气固化聚氨酯（MCPU）预聚物。采用标准丙酮-二丁胺法、傅里叶变换红外光谱法、凝胶色谱法和热重分析法来测定反应前后异氰酸酯基团的变化、预聚物分子量、热分解动力学参数以及MCPU膜的寿命。结果表明，预聚物的数均分子量为749，重均分子量为1684。预聚物中的异佛尔酮基团与空气中的水分反应形成无色、透明、柔韧的薄膜。MCPU膜的热分解为一级反应，分解过程包括两个阶段。利用达金方程得到热老化方程lg t = 4600.82/T - 8.07，这意味着在15℃时，样品的寿命约为150年。开发了一种新型保护材料，并研究了其热分解动力学，这对于潮湿环境中脆弱有机文物的保护具有重要意义。
