Hygroscopicity of Waterlogged Archaeological Wood from Xiaobaijiao No.1 Shipwreck Related to Its Deterioration State
Hygroscopicity of Waterlogged Archaeological Wood from Xiaobaijiao No.1 Shipwreck Related to Its Deterioration State
复制标题
小白礁一号沉船浸水考古木材的吸湿性与其劣化状态相关
DOI：
10.3390/polym12040834
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发表时间：
2020-04-01
期刊：
影响因子：
5
通讯作者：
Yin, Yafang
中科院分区：
文献类型：
--
作者：
Han, Liuyang;Guo, Juan;Yin, Yafang
浸水考古木（WAW）文物，由天然生物可降解聚合物制成，是许多珍贵文化遗产的重要组成部分。了解不同变质状态下WAW的吸湿特性，对于制定最佳干燥工艺和选择不同条件下的安全贮存具有重要意义。本文以小白角1号沉船上采集的两份hope （Giam）和两份Tectona (Teak) WAW样品为例进行了研究。采用最大含水量法（MWC）和细胞形态结构评价WAW的变质状态。Hopea WAW和Tectona WAW均可分为中度和轻度衰减WAW。然后利用动态蒸汽吸收（DVS）测量和两种吸收拟合模型比较研究了中度和轻度衰减WAW的吸湿行为。WAW细胞壁的成分分析和羟基可及性测量与不同变质状态下WAW的吸湿性相关。结果表明，中度腐烂的WAW比轻度腐烂的WAW具有更高的吸湿性和滞回性，这是由于WAW中多糖的相对含量较低，木质素的相对含量较高，木聚糖的o -乙酰基水解缓慢，β-O-4连接部分断裂，羟基可及性增加。这项工作有助于决定在沉船修复中建议采取哪些加固措施，即在木材干燥期间使用特定加固措施进行预处理，特别是在博物馆中展出的木制文物。
Waterlogged archaeological wood (WAW) artifacts, made of natural biodegradable polymers, are important parts of many precious cultural heritages. It is of great importance to understand the hygroscopic behavior of WAW in different deterioration states for the development of optimal drying processes and choices of safe storage in varying conditions. This was investigated in a case-study using two Hopea (Giam) and two Tectona (Teak) WAW samples collected from the Xiaobaijiao No.1 shipwreck. The deterioration state of WAW was evaluated by the maximum water content (MWC) method and by the cell morphological structure. Both Hopea and Tectona WAW could be classified into moderately and less decayed WAW. The hygroscopic behavior of moderately and less decayed WAW was then comparatively investigated using Dynamic Vapor Sorption (DVS) measurements alongside two sorption fitting models. Compositional analysis and hydroxyl accessibility measurements of WAW cell walls were shown to correlate with the hygroscopicity of WAW in different deterioration states. It was concluded that moderately decayed WAW possessed higher hygroscopicity and hysteresis than less decayed WAW because of the lower relative content of polysaccharides and the higher relative content of lignin, including the slow hydrolysis of O-acetyl groups of xylan and the partial breakage of β-O-4 interlinks, accompanied by an increased hydroxyl accessibility. This work helps in deciding on which consolidation measures are advised for shipwreck restauration, i.e., pretreatments with specific consolidates during wood drying, particularly for wooden artifacts displayed in museums.