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According to the environmental conditions of acid rain and fog in Dazu， Chongqing， the corrosion resistance of traditional gold glue paint used for gilding of cultural relics to wet polluted atmosphere was studied by a variety of simulated accelerated aging tests and combining with analytical methods such as infrared spectroscopy， contact angle， and morphology observation.Results showed that atmospheric acid rain pollution accelerated the impact of the alternating wet and dry environment of water on gold glue paint.Additionally， light， humidity and the alternating wet and dry environment of polluted atmosphere had varying degrees of influence on gold glue paint.Among them， the alternating dry and wet environment of polluted atmosphere possessed the most serious damage to the aging resistance of gold glue paint， which eventually led to the corrosion damage of gold gule paint materials.

Palm leaf manuscripts (PLMs), venerable historical artefacts containing Buddhist scriptures, history, mathematics and literature, which are carried by palm leaves (Corypha umbraculifera) and are highly susceptible to microbial degradation during prolonged storage. This degradation results in significant alterations to both the appearance and material properties of PLMs, but the precise mechanism underlying this deterioration remains a mystery. To this end, the present study focused on ancient PLMs from Xishuangbanna Dai Autonomous Prefecture in Yunnan Province, China. The objective of present study was to isolate, culture and identify the microorganisms typically found in these manuscripts and to use them to biodegrade the carriers of PLMs. Detailed observations of the biodegradation behavior of these microorganisms on the carriers of PLMs were carried out, together with characterizations of the hierarchical structure and mechanical properties of the leaf fiber cell walls. This comprehensive analysis provided insights into the deterioration mechanisms of the carriers of PLMs. The study revealed the presence of the common fungus Aspergillus niger on ancient PLMs. Aspergillus niger can secrete cellulase, lipase, and acidic substances after colonizing on the carriers of PLMs. These substances sequentially damage the carrier's epidermal cells, mesophyll cells, and leaf fibers, leading to the separation of different tissue structures. At the molecular level, the lipids on the surface of the leaves were degraded initially, and sequential depolymerization of hemicellulose, amorphous cellulose, and crystalline cellulose occurred. Additionally, this study firstly applied nanoindentation technology in the research of PLMs. The mechanical properties of the cell walls underwent notable alterations due to the modifications in chemical and crystalline structure of the carriers of PLMs upon the biodegradation of Aspergillus niger. Specifically, the hardness and elastic modulus of leaf fiber cell walls showed an initial increasing and then decreasing trend, consistent with the trend of cellulose crystallinity, which also provided a new reference for assessing the degree of deterioration of PLMs. [ABSTRACT FROM AUTHOR]

Palm leaf manuscripts were a prevalent literary medium from South Asia and Southeast Asia prior to the widespread use of paper. This study focuses on the analysis of historical palm leaf manuscripts from South and Southeast Asia. Sample palm leaf manuscripts from Burma were used as a case study; simulated palm leaf manuscripts were also created as a reference for comparison. The anatomy, chemical composition, and mechanical properties of the manuscripts were analyzed to find various forms of deterioration, including damage, fractures, pollution, acidification, and microbial deterioration. Specifically, the S1–S3 layers of the cell walls exhibited complete cracking, and the S2 layer showed numerous circular or nearly circular cavities caused by microbial erosion, while the middle lamella remained intact. The severe degradation of polysaccharides and pectin, accompanied by an increase in the relative content of lignin, caused the historical manuscripts to become more brittle. Additionally, the tensile strengths of historical palm leaf manuscripts were markedly reduced; their longitudinal tensile strength was significantly greater than their transverse tensile strength. This study can contribute to a better understanding of the deterioration process of historical palm leaf manuscripts and provide valuable insights for their restoration and preservation. [ABSTRACT FROM AUTHOR]

Waterlogged archaeological wood samples may degrade during long-term immersion in microbial-activity environments, which causes its biodegradation. Simultaneous dynamic vapor sorption (SDVS) and two-dimensional correlation infrared (2D COS-IR) spectroscopy reveal the degradation inhomogeneity of waterlogged fir wood from the Shengbeiyu shipwreck. The waterlogged and reference wood exhibit type II sorption isotherms. The equilibrium moisture contents of waterlogged archaeological fir wood from a decay region (WFD) were 22.5% higher than those of waterlogged archaeological fir wood from a sound region (WFS). WFD exhibits a higher measurable sorption hysteresis than WFS, implying greater variation in the surface moisture content in the WFD region compared to the WFS region, which may compromise the dimensional stability of the shipwreck. 2D COS-IR spectra confirmed the inhomogeneous degradation of the waterlogged wood via numerous mechanisms. The efficacy of SDVS and 2D COS-IR spectroscopy in the evaluation of the degradation state of waterlogged wood was demonstrated. This study verifies the existence of hygroscopic and chemical differences between visually similar samples from the same shipwreck. [ABSTRACT FROM AUTHOR]

Thermogravimetry (TG) is used to measure the change of sample mass versus temperature or time under a program controlling temperature. It is a common thermal analysis tool with a precise built-in balance, and accurate data can be obtained through a small amount of sample at the level of milligrams. The feasibility of the TG method for determining maximum water content (MWC) measurement of waterlogged archaeological wood was studied. Simulated waterlogged wood and waterlogged archaeological wood were used to determine the test condition for the TG method. MWC data obtained through the oven-dry and TG methods with different mass gradients from 0–10 mg to >50 mg were analyzed statistically. Deviation, error bar, and coefficient of variation were evaluated. According to the results, when sample mass is no less than 30 mg, and holding time at 105°C is no less than 40 min, data deviation between these two methods is less than 5%. Effect of sampling depth and presence of inorganic deposits were also investigated. Specimens were taken from an archaeological wood with a sampling depth from 2 to 6 mm, then MWC was measured through the TG method. The results indicate MWC of the samples taken from a depth of 2–4 mm is higher than that taken from a depth of 0–2 mm and is lower than that taken from a depth of 4–6 mm, which is related to inorganic deposits. The presence of deposits was verified through SEM-EDX. MWC of three archaeological wood samples from China and five archaeological wood samples from Italy were measured to verify the effectiveness of the TG method when wood species and degradation degree are different. [ABSTRACT FROM AUTHOR]

Waterlogged archaeological wood (WAW) undergoes biological deterioration during long-term immersion in microorganisms-rich aquatic environments. The consolidants are commonly applied to avoid wood deformation upon drying. It is urgent to develop a systematic evaluation method to study the impact of the consolidant distribution and the intermolecular interactions among consolidants and cell wall components on the improvement of wood mechanical traits. In order to evaluate the effect of consolidant distribution and intermolecular interactions between consolidants and cell wall components on the mechanical improvement, herein, we proposed in situ analysis methods involving Nanoindentation (NI) technology (without prior embedding) along with attenuated total reflection Fourier transform infrared imaging (ATR-FTIR imaging). Moreover, PEG, sucralose, and trehalose were chosen as representative consolidants to treat moderately deteriorated WAW because of their different molecular weights and different hydrophilic groups. Results showed that the mechanical improvement in consolidated WAW was significant. The elastic modulus and hardness of WAW after consolidation with PEG, sucralose and trehalose increased, with improvements of 15.3% and 34.8%, 43.9% and 49.5%, 31.9% and 6.4%, respectively, compared to untreated WAW. All three consolidants were found under scanning electron microscopy (SEM) to have filled wood cell lumens and mesopores in cell walls to different extents. ATR-FTIR imaging and thermogravimetric analysis (TGA) results further indicated that consolidants partly penetrated the wood cell walls. PEG was more concentrated near the fiber lumina. In addition, TGA revealed that the relative contents of PEG and trehalose in consolidated archaeological woods were 54.0% and 39.8%, and the maximum decomposition temperature (T d) of consolidated WAW all differed from the untreated WAW, which suggested non-covalent intermolecular interactions were probably presented between consolidants and WAW cell wall components. • Non-embedding sample preparation of Nanoindentation was developed for hydrophilic consolidants treated archaeological wood. • Nanoindentation method is feasible to characterize the mechanical property of consolidated archaeological wood. • ATR-FTIR imaging method proved distribution regularities of consolidants in cell wall of consolidated archaeological wood. • Consolidants PEG, sucralose and trehalose had interacted with cell wall components. [ABSTRACT FROM AUTHOR]