天然树脂加固淹埋木质文物

Reinforcement of buried and waterlogged wooden relics by natural resins

为了对剑川海门口遗址出土的古思茅松进行实验性加固保护,对古思茅松进行草酸脱色、甲醇溶剂脱水,然后使用松香和虫胶的甲醇溶液作为加固剂进行渗透、干燥等加固工序。加固后的样品表面色泽浅淡,保持了木材原有的色泽、纹理和质感。基本密度达到0.437g/cm3,已接近现代木材的基本密度。顺纹抗压强度较加固前增加了24.58%。绝干状态时测得的各向全干收缩率分别为:纵向2.22%、径向3.54%、弦向7.73%,均在正常木材干缩变化范围之内。扫描电子显微镜(SEM)研究表明:天然树脂附着在细胞壁表面,对细胞壁起到了足够的支撑作用,加固后的木材细胞壁切面平整、致密、轮廓清晰,胞壁间界面结合好,细胞腔较光滑。研究表明,本加固方法能有效降低木质文物的吸湿性、提高其各项物理力学性质。当木质文物需做其它处理时只需用甲醇或乙醇将松香和虫胶溶出即可,加固过程可逆,这解决了木质文物将来的再处理问题。

To reinforce ancient Pinus kesiya wood excavated from the Haimenkou site at Jianchuan, oxalic acid was used to for de - colorization, methanol for dehydration and rosin and shellac in methanol for enhancement. The whole enhancement process includes penetration and drying, and protection by experimental reinforcement. After reinforcement, the surface of the sample had a light color that preserved the original wood color, grain and texture. The density of the treated wood is 0. 437 g./cm3, close to its modern counterpart. The parallel - to - grain compres- sive strength increased by 24.6% after reinforcement. Shrinkage rate, when the wood when completely dried, was ： longitudinal direction, 2.2% ; radial 3.5% ; tangential, 7.7%. All shrinkage rates are within the normal rates seen when wood is dried. Scanning electron microscope （SEM） study showed that the natural resin stayed on the surface of the cell walls, providing great support for them. After reinforcement, the cell walls of the treated wood were smooth, dense and had clear outlines. There was good interface bonding between the cell walls, and the cell cavity was relatively smooth. This research shows that this reinforcement method can effectively decrease the hygro- scopic properties of waterlogged wooden relics and improve their physico - chemical properties. When necessary, methanol or ethanol can be used to dissolve the rosin and shellac used, which means the treatment is reversible, al- lowing for the possibility for other, future treatment.