Aging study of palm-leaf manuscript based on carbonyl index and construction of deterioration characterization model

As key carriers of plant-fiber manuscripts, palm leaves’ aging behavior under temperature and humidity is crucial for their preservation. This study examined accelerated aging of palm leaf samples at 50 °C and 100 °C for 30 days using microscopy, color analysis, FTIR, and XRD. At 100 °C, lightness L* decreased, while chromaticity a* and b* increased, with color differences reaching 250% compared to 50 °C. FTIR revealed intensified C=O and C–O peaks and rapid accumulation of the carbonyl index (CaI). XRD showed increased relative crystallinity, indicating preferential degradation in amorphous regions. A preliminary predictive model relating temperature to CaI was established and correlated well with Arrhenius-based estimates. These results confirm the utility of the carbonyl index for evaluating degradation and provide a basis for preservation strategies for palm leaf manuscripts.