聚醋酸乙烯酯乳液的表征、性能及其在彩绘类文物保护中的应用  

Characterization,property and application of PVAc emulsion as a kind of conservation material for painted cultural relics

作　　者：李燕飞[1,2,3] 赵林毅[2,3] 王磊 方晓芸 李菱志 LI Yanfei;ZHAO Linyi;WANG Lei;FANG Xiaoyun;LI Lingzhi(Conservation Research Institute, Dunhuang Academy, Jiuquan 736200, China;National Research Center for Conservation of Ancient Wall Paintings and Earthern Sites(Dunhuang Academy), Jiuquan 736200, China;Key Scientific Research Base of Conservation for Ancient Mural (Dunhuang Academy), State Administration for Cultural Heritage, Jiuquan 736200, China;Technical Service Center of Cultural Relic Conservation, Dunhuang Academy, Jiuquan 736200, China;Gansu Mogao Grottoes Cultural Heritage Protection Design Consulting Co. , Ltd. , Jiuquan 736200, China)

机构地区：[1]敦煌研究院保护研究所,甘肃酒泉736200 [2]国家古代壁画与土遗址保护工程技术研究中心(敦煌研究院),甘肃酒泉736200 [3]古代壁画保护国家文物局重点科研基地(敦煌研究院),甘肃酒泉736200 [4]敦煌研究院文物保护技术服务中心,甘肃酒泉736200 [5]甘肃莫高窟文化遗产保护设计咨询有限公司,甘肃酒泉736200

出　　处：《文物保护与考古科学》2021年第4期22-32,共11页Sciences of Conservation and Archaeology

基　　金：国家重点研发计划项目资助(2019YFC1520700)。

摘　　要：聚醋酸乙烯酯(PVAc)乳液是常见的彩绘类文物保护材料。采用激光粒度仪、热重/差热分析、红外光谱、X-射线衍射、扫描电镜、透射电镜等表征了PVAc乳液的粒径以及胶膜的热稳定性、结构和形貌;采用粘度计、表面张力仪、pH计、电导率仪等研究了乳液浓度与其粘度、表面张力、pH、电导率的关系;通过冻融、室温-高温放置、离心分离研究了乳液的稳定性;同时用PVAc乳液对模拟起甲和酥碱的壁画进行了修复。结果表明,PVAc乳液粒径呈双峰分布,小粒子的平均粒径为380 nm,大粒子的平均粒径为5.85μm;乳液胶膜为非结晶物质,胶膜热重的最终质量残留为1.54%,335℃出现放热峰。PVAc乳液的电导率随浓度的增大而增大,pH随浓度的增大而下降;相同温度下表面张力随浓度的增大而基本呈现低浓度下降,高浓度上升的趋势。相同浓度下,表面张力随温度升高而无显著变化,表明PVAc乳液的表面张力受温度变化影响不大。相同温度下,乳液粘度随浓度的增大而增大;相同浓度下,乳液的粘度随温度的升高而降低。冻融、离心分离和不同温度下静置发现,该乳液出现分层。用该乳液对模拟起甲和酥碱壁画修复后,再分别老化20个循环和12个循环,发现颜料层再次空鼓、起甲。综合分析,说明实验中所使用的该种PVAc稳定性和抗老化能力较弱,在修复彩绘类文物中应慎重选择PVAc的种类,综合考虑PVAc的使用浓度、环境因素对其性能的影响,以达到最佳使用效果。Polyvinyl acetate(PVAc)emulsion is a common conservation material used for conservation of painted cultural relics.In this study,the thermal stability,structure,morphology and particle size of PVAc emulsion were characterized and analyzed using thermogravimetric-differential thermal(TG-DTG)analyzer,Fourier transform infrared(FT-IR)spectrometer,X-ray diffractometer(XRD),scanning electron microscope(SEM),transmission electron microscope(TEM)and laser particle size analyzer.The relationship between the concentration of PVAc emulsion and its viscosity,surface tension,pH value and conductivity were investigated using a viscometer,surface tension meter,pH meter and conductivity meter,respectively.The stability of the PVAc emulsion was examined by freezing and thawing test,room temperature-high temperature placement,and centrifugal separation.In addition,to further verify its properties,the PVAc emulsion was used for the restoration of flaking and disrupted murals.The results show that 1)the particle size of the PVAc emulsion was bimodal,the average particle size of small particles was 380 nm and the average particle size of large particles was 5.85μm;2)the final mass residue of the film was 1.54%,the exothermic peak appeared at 335℃,and the emulsion was of amorphous structure;3)with the increase of the PVAc emulsion concentration,the surface tension decreased and the relative viscosity increased;4)PVAc emulsion is stratified by freeze-thaw,centrifugal separation and room temperature-high temperature placement.After repairing the flaking and disrupting murals,the samples are cycled for 20 times and aged for 12 times,respectively.It was found that the repairing murals were again flaking and disrupting.All results suggested that the PVAc emulsion used in this work has poor stability and anti-aging performance.Therefore,during the restoration of painted cultural relics,the influence of PVAc type,PVAc concentration,and environmental factors on its performance should be carefully selected to achieve the best effect in use

关 键 词：彩绘类文物 文物保护 粘合剂 聚醋酸乙烯酯(PVAc)乳液 

分 类 号：K879.4[历史地理—考古学及博物馆学]