Study on the hygroscopicity and kinetic and thermodynamic properties of ancient Tibetan Palm Leaf Manuscripts
摘要
This study examines how natural aging affects the hygroscopic, kinetic, and thermodynamic properties of ancient Tibetan Palm Leaf Manuscripts. The results show aging increases equilibrium moisture content and hygroscopicity, with a noticeable hysteresis effect, suggesting enhanced moisture stability at low to moderate humidity. The GAB and H-H models indicate aging accelerates cellulose degradation, adds adsorption sites, and promotes physical adsorption. Kinetic studies reveal a faster moisture absorption and release rate with aging, especially under varying humidity. Thermodynamic analysis shows that as moisture content rises, the adsorption and desorption processes become more spontaneous. Infrared spectral analysis confirms significant degradation of cellulose and hemicellulose, increasing hydroxyl groups and hygroscopicity. The study suggests that these manuscripts are best preserved in a controlled environment with moderate humidity (50-60% RH) and cooler temperatures to maintain moisture stability and flexibility while preventing damage from excessive fluctuations.