Multi-Analytical Assessment of Deterioration in the Qianlong Tripitaka Wooden Scripture Plates

The Qianlong Tripitaka preserved in the Capital Museum is a distinctive large-scale wood block printing plates of the Qing Dynasty. It represents a unique type of Chinese documentary wooden heritage preserved in a dry museum environment, which has rarely been subjected to comprehensive physicochemical analysis, resulting in an inadequate understanding of their deterioration processes. This study applied a comprehensive multi-analytical method to investigate the deterioration of the scripture plates. The findings indicate that the Qianlong Tripitaka shows typical structural deformation, chemical depolymerization, and a decline in structural integrity and stability. Scanning Electron Microscopy (SEM) and Computed Tomography (CT) revealed thinning and the distortion of cell walls, reduced density, and partial collapse of tissue structures. Thermogravimetric Analysis (TGA) indicated lower decomposition temperatures and higher inorganic residues, while a Brunauer-Emmett-Teller surface area analyzer (BET) showed diminished surface area, expanded pores, and compromised connectivity. Moisture content analyses verified significant water loss, contributing to brittleness and susceptibility to microbial degradation. Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) analyses revealed considerable hemicellulose degradation, the disruption of cellulose crystallinity, and relatively stable lignin. This study highlights the value of a multi-analytical strategy for assessing the deterioration of wooden cultural heritage, providing a transferable framework for similar documentary wooden artifacts.