出土脆弱、黏结丝织品文物自分层揭展技术研究

发布时间：2018-04-26 15:38

本文选题：自分层 + 脆弱　；参考：《中国科学技术大学》2017年博士论文

【摘要】：丝织品文物是中华文明史中浓墨重彩的一笔,其种类繁多、工艺精美,是古代中国劳动人民智慧的集中展现,具有极高的历史、科研、艺术价值。但出土丝织品文物经过长时间的埋藏,大多数腐蚀殆尽、不见踪迹,极少数保留下来的也多半糟朽不堪、触之即粉。丝织品文物的出土状况通常呈现出两个共性:严重糟朽、层间黏结。由于出土纺织品文物在埋藏过程中多数是折叠放置的,历经千百的埋藏之后,层与层之间发生黏结,折痕处断裂或极易断裂。为使埋藏地下的瑰宝重焕光彩,揭展无疑是纺织品文物保护、修复工作的首要工作。因此,利用现有的科学技术改善出土纺织品黏结、糟朽的现状就是揭展工作要解决的最主要问题。目前,针对丝织品文物揭展剂和揭展技术的研究主要是利用物理、化学、生物的手段,通过降低丝织品层间黏结的作用力,完成出土丝织品的揭展工作。揭展剂的化学成分多数为表面活性剂、柔软剂、渗透剂等生化助剂,可有效的降低丝织品层间黏结强度。然而脆弱出土丝织品文物即使成功降低层间黏结力,因丝织品自身强度太差,揭展工作仍会对丝织品文物有一定的损毁。丝织品文物满足揭展的关键在于:丝织品本体强度足够克服丝织品层间黏结的强度。也就是说,解决揭展难题的途径可以概括为两种:增加丝织品本体强度、降低层间黏结强度。一般而言,降低丝织品层间黏结力和提升丝织品力学强度是难以调和的悖论,也是制约揭展技术发展的主要矛盾。若使用加固剂以提升丝织品强度,则会使其渗透至丝织品层间,从而增加黏结强度。若仅降低层间黏结,而忽略加强丝织品的强度,则无法满足揭展的需要。针对这一难题,本研究利用自分层技术对丝织品文物进行揭展,在降低丝织品层间黏结强度的同时,增强蚕丝纤维的力学强度。本研究选取多种文物保护常用材料,利用表面能理论对自分层材料混合液成膜后的分层情况进行理论预判。选择使用聚醋酸乙烯酯、硬脂酸钠作为自分层材料,再通过扫描电子显微镜对样品进行观察,验证分层效果,确认硬脂酸钠、聚醋酸乙烯酯混合乳液符合自分层揭展前提条件。在此基础之上,将自分层揭展技术运用于模拟脆弱黏结丝织品的揭展中。通过剥离强度、抗拉强度表征揭展效果,对揭展剂浓度配比、作用时间设计正交试验。最终确认最优方案为硬脂酸钠浓度0.5%,聚醋酸乙烯酯浓度0.5%,作用时间为4h,揭展效果较好。使用聚焦离子束(FIB)加工技术对揭展剂膜进行刻蚀,获取了揭展剂膜不同深度的梯度空间样品,实现对样品做不同深度的立体分析。加工后样品分别用于原子力显微镜(AFM)分析、X射线光电子能谱(XPS)分析。扫描电子显微镜对揭展剂膜进行观察,发现薄膜纵向出现明显分层现象。通过比较上下表面、不同深度的揭展剂膜原子力相图发现:揭展剂膜上表面主要成分为硬脂酸钠,随着膜深度加深硬脂酸钠含量逐渐减少、聚醋酸乙烯酯含量逐渐增多,呈明显的梯度变化。利用对不同深度位置的X射线光电子能谱分析结果显示,揭展剂膜上表面、中间不同深度位置、下表面Na相对含量依次为5.05%、3. 03%、0.37%、0.42%,变化趋势明显。根据激光共聚焦拉曼定量分析聚醋酸乙烯酯在揭展剂膜的不同位置相对含量结果依次是:18. 7%、22%、、61.7%、69. 2%,浓度存在梯度变化。因此,原子力显微镜、X射线光电子能谱、激光共聚焦拉曼的分析结果共同验证了自分层揭展剂组分的分层情况。将自分层揭展技术应用于模拟样品、荆州谢家桥一号汉墓、荆州夏家台楚墓、南陵铁拐宋墓出土丝织品残片的揭展工作。利用超景深光学显微镜对各样品揭展效果进行观察,对比发现,样品在揭展前后无明显变化。使用扫描电子显微镜观察丝织品揭展前后微观形貌,则发现蚕丝表面形成了薄的包裹层。色差分析结果表明,模拟样品、谢家桥样品、南陵样品、夏家台样品的色差平均值依次是0. 82、0.56、0.96、0.70,符合文物保护的色差变化范围。对各个样品进行硬挺度测试发现,模拟样品、古代样品揭展后的悬垂硬挺度、抗弯刚度均较揭展前有大幅下降,说明黏附在蚕丝表面的黏结物、污染物在揭展过程中被部分清洗。揭展剂的使用在一定程度上也增加了蚕丝的柔软度。模拟样品、古代样品热重分析结果表明,使用揭展剂后,丝织品的热稳定性和热分解速率受揭展剂成分影响发生了部分改变。对比模拟样品、古代样品动态热机械分析结果后发现,揭展后丝织品抗拉强度有明显升高,断裂伸长率变化不明显。揭展属于整个丝织品文物保护工作中前序阶段,揭展剂必需具备良好的可再处理性才能符合现阶段文物保护的需要。因此,本研究采用等温滴定量热技术、热重分析、示差扫描量热分析对自分层揭展技术的可再处理性进行了评估,实验结果表明,其清除效果良好,进一步验证了自分层揭展技术的实际可操作性。通过对模拟样品、古代丝织品文物残片的揭展,综合考量揭展剂分层效果、揭展效果、揭展剂去除效果等因素。本研究将自分层揭展技术应用于湖北荆州谢家桥一号汉墓、安徽南陵铁拐宋墓、江西南昌海昏侯汉墓出土的不同时期、不同糟朽状况的珍贵丝织品文物(计20件)进行了揭展、揭取,均取得了较好的成果。丝织品文物的自分层揭展技术,改变了以往揭展技术以降低层间黏结强度为研究目的的单一途径。形成了以增加丝织品力学强度、降低丝织品黏结强度两者共同作用为目的的新研究视角,为丝织品文物揭展提供了新的思路和方法。自分层揭展技术的研究,也为其他类型文物的保护研究提供了一定的借鉴。
[Abstract]:Silk cultural relics are rich and heavy in the history of Chinese civilization, with a wide variety and exquisite craftsmanship. It is a concentrated display of the wisdom of the ancient Chinese working people. It has a high history, scientific research and artistic value. The unearthed condition of a silk cultural relic usually presents two commonalities: serious decay and interlayer bonding. Because most of the unearthed textile relics are folded in the course of burial, after hundreds of burial, the layers and layers are bonded, the creases are broken or very easily broken. No doubt, uncovering is the most important work for the protection of textile relics and repair work. Therefore, using the existing science and technology to improve the bonding of unearthed textiles is the most important problem to be solved. At present, the research of uncovering agents and uncovering techniques for silk fabrics is mainly the use of physical, chemical and biological hands. Section, by reducing the bonding force between the silk fabric, the soil silk fabric is uncovered. Most of the chemical components of the uncovering agent are surface active agents, softeners, and osmosis agents, which can effectively reduce the bond strength between the silk fabrics. As the body strength is too poor, the uncovering work will still have a certain damage to the silk cultural relics. The key of the silk cultural relics to meet the uncovering is that the strength of the silk is strong enough to overcome the bond strength between the silk fabrics. That is to say, the way to solve the problem can be summarized as two kinds: increasing the strength of the silk fabric and reducing the bond strength between the layers. It is an incompatible paradox to reduce the bonding force between the silk fabrics and enhance the mechanical strength of silk fabrics. It is also a major contradiction that restricts the development of uncovered technology. If the strength of silk is enhanced by the use of reinforcing agents, it will penetrate into the silk fabric and increase the bonding strength. If only the interlayer bonding is reduced, the strength of the silk fabric will be neglected. In order to solve this problem, this study uses self stratification technology to uncover the silk fabric and enhance the mechanical strength of silk fiber while reducing the bond strength between the silk fabrics. This study selects a variety of cultural relics to protect the common materials, and uses the theory of surface energy to form the self layered material after the film is formed. Polyvinyl acetate and sodium stearate are selected as self stratified materials, and then the samples are observed by scanning electron microscope to verify the stratification effect, and the sodium stearate is confirmed and the polyvinyl acetate emulsion conforms to the self delamination precondition. Based on this, the self delamination technology will be transported. It is used to simulate the uncovering of fragile bonded silk fabrics. Through the stripping strength, tensile strength characterizing the uncovering effect, the orthogonal test is designed for the concentration ratio of the uncovering agent and the action time. Finally, the optimum scheme is that the optimal solution is 0.5% of sodium stearate, 0.5% of the concentration of polyvinyl acetate, the effect time is 4h, and the effect of uncovering is better. Focusing ion beam (FIB) is used. The technology was used to etch the film of the uncovering agent, obtain the gradient space sample with different depth of the film and realize the stereoscopic analysis of the different depth of the sample. The samples were used for atomic force microscope (AFM) analysis, X ray photoelectron spectroscopy (XPS) analysis. By comparing the upper and lower surfaces, the atomic force phase diagram of the uncovering agent membrane in different depths shows that the main component of the surface of the film is sodium stearate, and the content of sodium stearate gradually decreases with the depth of the membrane, and the content of polyvinyl acetate increases gradually. The X ray light of different depth positions is used. The results of electronic energy spectrum analysis show that the relative content of Na in the upper surface of the film is 5.05%, 3.03%, 0.37%, 0.42%, and the change trend is obvious. According to the laser confocal Raman Raman quantitative analysis, the relative content of polyvinyl acetate in the film of the uncovering agent is 18.7%, 22%, 61.7%, 69.2%, and strong. There is a gradient change. Therefore, atomic force microscopy, X ray photoelectron spectroscopy and laser confocal Raman analysis jointly verify the stratification of the self stratified uncovering agent components. The self stratified uncovering technology is applied to the simulated samples, the tomb of the No. 1 Han tomb in Shijia bridge in Jingzhou, the chusantai tomb in Jingzhou, and the remnants of the native silk fabrics in the tombs of the iron Guixiang of Nanling. It is found that the sample has no obvious change before and after uncovering. Using scanning electron microscope to observe the micromorphology before and after the uncovering of silk fabrics, it is found that the silk surface forms a thin layer of wrapping. The color difference analysis results show that the sample, Shijia bridge, is the sample. The average color difference of the Nanling sample is 0. 82,0.56,0.96,0.70, which is in line with the color difference range of cultural relic protection. The use of the dye was partially cleaned during the uncovering process. The use of the uncovering agent also increased the silkworm softness to a certain extent. The results of the analogue samples. The results of the thermogravimetric analysis of the ancient samples showed that the thermal stability and the thermal decomposition rate of the silk fabrics were partly influenced by the composition of the uncovering agent after using the uncovering agent. The results of the thermal mechanical analysis showed that the tensile strength of the silk fabric increased obviously and the elongation at break was not obvious. The uncovering was the preorder stage of the whole silk cultural relic protection work, and the uncovering agent must have good reprocessing ability to meet the needs of the present protection of cultural relics. Therefore, the isothermal titration was used in this study. The reprocessing property of the self delamination technology is evaluated by thermogravimetry, thermogravimetric analysis and differential scanning calorimetry. The results of the experiment show that the removal efficiency is good and the practical operability of the self delamination technology is verified. In this study, the self delamination technology was applied to the Han Tombs No. 1 in Jingzhou, Hubei, the tomb of the Nanling iron guikuo in Anhui, and the different periods of the unearthed Tomb of the Han tomb in the Nanchang sea of Nanchang, Jiangxi, and the precious silk cultural relics (20 pieces) with different rotten conditions were uncovered and taken out. The self delamination technology of silk fabric has changed the single way to reduce the interlayer bonding strength in the past. A new research perspective has been formed to increase the mechanical strength of silk fabrics and reduce the bonding strength of silk fabrics, which provides a new way of thinking and method for the uncovering of silk fabrics. The research of layer unfolding technology also provides some reference for the protection research of other types of cultural relics.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TS146;K876.9

【参考文献】