利用FT-IR、Py-GC/MS和THM-Py-GC/MS微损分析技术探索油画文物复杂的有机基质组成

近现代油画有机基质组分复杂、难辨，其分析鉴定是当今文物保护科技研究的难点之一。利用微损分析技术研究油画文物复杂的基质结构、材料和技法，可以阐明油画特定层的性质和状况，对于专业保护人员制定修复决策至关重要——这对选择正确修复技术非常有用，关系到修复后油画的安全状态，因此已成为许多研究者关注的焦点。本研究利用傅里叶变换红外光谱(FT-IR)、热裂解气相色谱-质谱(Py-GC/MS)和热辅助水解甲基化-裂解气相色谱-质谱(THM-Py-GC/MS)等微损分析技术对一幅中国国家博物馆藏油画《德涅泊尔河的秋天》进行科技分析。研究发现，综合运用这些微损分析技术可以有效识别油画用的胶结介质和其中添加剂的种类，最大限度、准确、完整地提取样品中所蕴含的信息。结果表明，该油画的有机胶结材料为聚乙烯醋酸酯类材料和亚麻籽油，同时聚乙烯醋酸酯类材料中使用了邻苯二甲酸二丁酯作为增塑剂。裂解产物中不含光油树脂类成分，说明画作下部的光亮层并非作者有意上的光油层。此外，油画部分区域还添加了蜂蜡作为改性材料，起到增加颜料稠度、可塑性和减弱光泽的作用。

Exploring the complex organic matrix composition of oil painting artifacts using micro-destructive analysis techniques of FT-IR, Py-GC/MS and THM-Py-GC/MS

Organic matrix components of modern oil paintings are complex and difficult to identify, and their analysis and identification is one of the difficulties in today’s scientific and technological research on the conservation of cultural relics. The use of micro-destructive analysis methods to investigate the structure, materials and techniques for complex oil painting matrices can elucidate the nature and condition of specific layers of painting. These physicochemical findings are crucial for conservation professionals to make restoration decisions as to the correct handling and concern the future state of restored painting, and thus have become a focus of attention for many researchers. In this paper, FT-IR, Py-GC/MS and THM-Py-GC/MS micro-destructive techniques were used to analyze the scientific and technological characteristics of an oil painting, Autumn on the Dnieper River, in the collection of the National Museum of China. It was found that the combination of these micro-destructive analysis techniques could effectively identify the binding media used for the oil painting and the type of additives present therein to maximally, accurately and integrally extract the information contained in the sample. The results show that the organic cementing materials for the oil painting are polyvinyl acetate materials and linseed oil, while dibutyl phthalate was used as a plasticizer in the polyvinyl acetate materials. The absence of varnish resin-like components in the pyrolysis products suggests that the glossy layer on the lower part of the painting is not the layer of varnish that the author intended to put on. In addition, beeswax was added to some areas of the painting as a modifying material that serves to increase pigment consistency and plasticity, and also to diminish gloss.