The Effect of Aluminum Ions on the Acidification and Aging of Paper

Abstract

Abstract Paper documents provide important records of human civilization and so understanding the causes of paper document aging is very important to delay the process and prolong the lifespan of paper. This study used an anionic rosin as a sizing agent and aluminum sulphate as a fixing agent, to produce paper with different amounts of aluminum sulphate. The effect of different contents of aluminum ions on the acidification and aging of the paper was studied by accelerated aging experiments. The results showed that the presence of aluminum ions in paper could accelerate the acidification and aging process, and the higher the content of aluminum ions, the worse the durability of paper. In the process of accelerated aging, with increasing aluminum ion content, the rate of decline in the strength and whiteness of paper increased whilst the pH value decreased. Accelerated aging under the same conditions for 15 days caused the pH value, whiteness, tensile index and tear index of paper without aluminum ions to decrease by 14.77%, 3.15%, 7.99% and 11.70% respectively. In comparison, paper which had aluminum sulphate added to 30 kg per ton of paper, showed the decreases of pH, whiteness, tensile index and tear index by 22.62%, 4.35%, 24.66% and 31.07% respectively.