Deacidification and reinforcement of old books using sodium carbonate and latex composites

Old books suffer from aging and deterioration spurred by acidification, oxidation, and other factors. To preserve the important historical documents, a de-acidification and reinforcement method was studied using ultrasonic atomization via deacidification by Na2CO3 solution and styrene acrylic latex composite as reinforcing agent. These agents were atomized into micron-sized droplets and were absorbed by paper. In this study, the physical properties, internal structure, and surface morphology of the paper before and after aging were comprehensively studied for explaining the treatment mechanism. The paper pH, strength properties, brightness, color difference, and apparent morphology typically have been determined in detail as the important factors for evaluating the treatment effect of the preservation method for old paper. The analysis results showed that the pH of the paper after deacidification was successfully increased. Thus, even after aging, the pH of the deacidified paper was still higher than 7. The change of color difference of paper after treatment was not noticeable, meeting the requirement for the basic principle of an old book. Furthermore, the deacidification treatment had no clear influence on the breaking length and tear index of the paper. This study revealed a new perspective on the conservation of old books.