合成碳酸钙分散稳定性调控及其对纸质文献脱酸效果研究

Research on the Regulation of Dispersion Stability of Synthetic Calcium Carbonate and Its Effect on Deacidification of Paper-based Documents

关键词:  纸质文献保护  脱酸  合成碳酸钙  甲基纤维素

Key Words:paper-based document protection  deacidification  synthesis calcium carbonate  methylcellulose

摘要:本研究提出了以甲基纤维素为分散助剂，对合成碳酸钙分散体系的粒径和分散稳定性进行调控的研究策略；并将合成碳酸钙分散体系应用于酸化纸质文献脱酸处理，并进行耐老化性能评估。研究发现，黏度为1 500 mPa·s的甲基纤维素与氢氧化钙以质量比1∶4在二氧化碳氛围中合成的碳酸钙分散体系具有最佳分散稳定性，碳酸钙的平均粒径为108 nm，静置5天仍保持稳定分散。碳酸钙分散体系处理后的旧书纸张的冷抽提pH值从4.7提升到7.7，碱储量为1.95%碳酸钙当量；经过湿热加速老化14天后，脱酸旧书纸张的冷抽提pH值仍保持7.5，碱储量为1.70%碳酸钙当量；脱酸处理后的旧书纸张机械性能明显高于未处理组，色差<1，对字迹油墨无影响，表明该体系对纸质文献具有优异的脱酸性能，并可赋予其耐老化性能。

Abstract:In this study， the particle size and dispersion stability of synthesized calcium carbonate dispersion system were regulated by methylcellulose as dispersion agent. Then the calcium carbonate dispersion system was applied to the deacidification of acidified paper literature， and the aging resistance was evaluated. The results showed that the calcium carbonate dispersion system synthesized in a carbon dioxide atmosphere using methylcellulose with viscosity of 1 500 mPa·s and calcium hydroxide at mass ratio of 1∶4 achieved optimal dispersion stability. The average particle size of the calcium carbonate was 108 nm， and it remained stably dispersed even after standing for 5 days. The pH value of the old-book paper treated with calcium carbonate dispersion system increased from 4.7 to 7.7， the alkali reserve was 1.95% calcium carbonate equivalent. After accelerated aging for 14 days， the deacidified old-book paper still maintained pH value was 7.5 and the alkali reserve was 1.70% calcium carbonate equivalent. The mechanical properties of the deacidified old-book paper were significantly higher than those of the untreated group， and the chromatic aberration was less than 1 which had no effect on the handwriting ink， indicating that the system had excellent deacidification and aging resistance to paper-based documents.