陶质彩绘文物保护材料有效寿命预测方法的探索性研究

文物保护材料有效寿命的预测是文博领域十分关注的科学问题。为此,本研究通过对仿真样品进行多组平行老化实验,借鉴动力学方法探究环境对纯丙(纯丙烯酸乳液)、硅丙(有机硅-丙烯酸乳液)及B72(Paraloid B72)等保护材料有效寿命的影响。实验包括三个部分内容:一、测量仿真样品上保护材料在不同老化条件下的接触角及色度变化,以表征其耐候性;二、测量紫外光照射时间不同保护材料的可逆率变化,以表征其耐光性;三、对三种材料做热重分析,并利用热动力学原理预测其热老化寿命。所得结果如下:一、通过对仿真样品的老化循环可以直观地表达三种保护材料的耐候性,发现与文物本体的"相容性"是三种材料失效的主要原因,在不同组的老化实验中,可以看出三种材料各有优劣;二、通过测量几种保护材料的"可逆率"发现,紫外光照射下纯丙、硅丙、B72均符合二级反应,可以此为依据通过计算的方法推测保护材料在紫外老化条件下的耐久性;三、通过数据可知,在稳定、低温环境下,高分子材料的耐久性均非常优异。随着环境温度升高,保护材料的有效寿命会明显缩短。本研究探索的结果,可为现阶段较常使用的文物保护材料的寿命预测提供一些思路。

Exploratory research on prediction of effective lifetimes of several typical materials used for the conservation of polychrome potteries

Evaluation of the failure of typical polymeric materials used to conserve polychrome potteries has long been a focus of conservators. In contrast to the pure polymers themselves, the rules for failure of these polymers when used for repair of polychrome potteries are more complicated. In this study, we explored the effective lifetimes of three typical conservation materials, namely pure acrylic emulsion, silicone acrylic emulsion and paraloid-B72. The macroscopic properties of the samples were measured to determine the strength of these materials. Reversible rates of the conservation materials were analyzed by photodecomposition curves and linear regression method to calculate the ages of the three materials in UV irradiation environments. Thermogravimetric analysis methods were used to predict thermal aging lifetimes. The results show that the conservation materials are more durable in stable environments than in those with variation in UV light, water or temperature. The study provides theoretical guidance for storage of fragile polychrome potteries which have been conserved using polymeric materials. Although the experiments and calculations in this paper have some limitations, this exploratory work offers a way to predict the lifetimes of cultural relic conservation materials.