EFFECT OF DRY- HEAT AND MOIST-HEAT AGING ON PROPERTIES OF PAPERS TREATED WITH NANO CALCIUM HYDROXIDE AND NANO CHITOSAN

Paper due to its structural properties, is gradually degraded by different destructive factors especially acidic hydrolysis. For this reason, deacidification of the old valuable papers in order to stop and neutralize this process and applying consolidation treatments for strengthening of degraded paper is necessary. In this study, for deacidification and consolidaton, by using dispersions of Nano Calcium hydroxide and Nano Calcium Hydroxide with companion of Nano Chitosan in Ethanol, a Nano coat was applied on the paper samples. Also, in order to investigate the effect of deacidification and consolidation treatments, the samples were subjected to dry-heat and moist-heat aging. Then, pH, folding endurance, and brightness of the treated aged and unaged papers were studied. The results of studying the chemical, mechanical and physical properties of treated papers before and after aging showed that the use of calcium hydroxide nanoparticles led to an increase in alkalinity improved the brightness, while using Nano chitosan with calcium hydroxide increased the mechanical properties of paper. But after moist-heat aging, the folding endurance of treated papers with Nano calcium hydroxide - Nano chitosan had more decrease. Also, in terms of optical properties, the papers treated with calcium hydroxide nanoparticles had more stability in comparison to control samples and treated papers with combination of Nano calcium hydroxide and Nano chitosan.