应用热辅助水解甲基化裂解气相色谱质谱技术对古代漆器漆膜的分析研究

为了改良漆器漆膜的性能,古代漆工在制作过程中通常向生漆中加入干性油等添加剂。为了确定生漆及添加剂的种类,本工作采用四甲基氢氧化铵(TMAH)作为甲基化试剂,利用热辅助水解甲基化裂解气相色谱质谱(THM-Py-GC/MS)技术对所选的参考样品进行分析,然后将成熟的方法和实验条件应用到古代漆器的分析研究中。在古代样品中检测出了3-十五烷基邻苯二酚(C15)、3-十五烯基邻苯二酚(C15:1)等来源于中国、日本地区种植的Rhus vernicifera树种的生漆的特征热裂解化合物,确定了所用生漆的种类。另外,本实验在古代漆器中检测到了棕榈酸、硬脂酸、庚酸、辛酸和壬二酸等脂肪酸,推断该漆膜中添加了干性油。利用三维视频显微镜、扫描电镜、X射线衍射分析方法发现古代漆器采用了在胎体上依次髹漆灰、底漆和色漆的髹漆工艺,其中漆灰主要由漆液和钠长石、石英调制而成,黑色漆膜的呈色颜料为含铁化合物,揭示了古代漆器的髹漆工艺。该研究结果不仅增强人们对古代漆器制作材料和工艺的科学认知,而且为保护漆器这一独特的文化遗产提供科学依据。

Research on the films of ancient lacquerwares by thermally assisted hydrolysis-methylation (THM) pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) analysis

In ancient times, drying oils and other additives were usually added to raw lacquer in the manufacture of lacquerwares for the purpose of improving the performance of lacquer film. In order to determine the types of the raw lacquer and additives, we first used thermally assisted hydrolysis-methylation pyrolysis-gas chromatography/mass spectrometry (THM-Py-GC/MS) to analyze the reference sample, and then applied the verified methods and experimental conditions to the study of ancient lacquerwares.The results show that 3-pentadecylcatechol(C15), 3-pentadecenylcatechol(C15:1), which are characteristic components of raw lacquer tapped from Rhus vernicifera, lacquer trees grown mainly in China and Japan, were found in the ancient samples. The type of raw lacquer was determined accordingly. In addition, some fatty acids such as palmitic acid, stearic acid, heptanoic acid, octanoic acid and azelaic acid were detected in the ancient lacquerwares, which are typical components of drying oil, indicating that drying oil was added to the lacquer films. Moreover, three-dimensional video microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were applied to reveal the lacquer-making techniques of the ancient lacquerwares described here. Ancient lacquerers applied ash, primer and color paint on the lacquer bodies successively. The black pigment is an iron compound, and the lacquer ash is made from lacquer, albite and quartz.