Aging effects of relative humidity on palm leaf manuscripts and optimal humidity conditions for preservation

Palm Leaf Manuscripts are valuable cultural assets, and understanding the impact of environmental factors on their properties is essential for effective conservation. This study simulated aging to assess the effects of relative humidity (RH) on the manuscripts using various techniques, including SEM, DVS, TMA, FT-IR, and XRD. The results show that exposure to extreme dry or humid conditions negatively affects the manuscripts. In dry conditions, they experience bending, cracking, reduced mechanical strength, lower hygroscopicity, and chemical degradation. In humid conditions, fungal growth compromises the manuscripts’ structure. These changes affect color, gloss, hygroscopic behavior, cellulose crystallinity, and thermal stability, weakening mechanical properties. Manuscripts stored at 50% RH showed no significant damage, suggesting that this level is optimal for their preservation. This study provides insights into the degradation mechanisms of Palm Leaf Manuscripts under different humidity conditions and offers recommendations for their preservation.