Banti Donatella, La Nasa Jacopo, Tenorio Anna Lluveras, Modugno Francesca, Jan van den Berg Klaas, Lee Judith, Ormsby Bronwyn, Burnstock Aviva, Bonaduce Ilaria
Courtauld Institute of Art Somerset House, Strand London WC2R 0RN UK.
Department of Chemistry and Industrial Chemistry, University of Pisa Via Moruzzi 13-56124 Pisa Italy
RSC Adv. 2018 Feb 6;8(11):6001-6012. doi: 10.1039/c7ra13364b. eCollection 2018 Feb 2.
The 20th century has seen a significant evolution in artists' paint formulation and technology which is likely to relate to the new conservation challenges frequently presented by modern oil paintings, including unpredictable water- and solvent-sensitivity. This study examined the molecular causes and mechanisms behind these types of modern oil paint vulnerability. Research performed up to now has suggested a correlation between the occurrence of water sensitivity and the presence of relatively high amounts of extractable free dicarboxylic acids. To explore this further, as well as the influence of paint formulation, a set of model paint samples, produced in 2006 using commercial tube paints to which known amounts of additives were added, were analysed. The samples were tested for water sensitivity by aqueous swabbing and characterised using transmission Fourier Transform-Infra Red spectroscopy (FTIR) to determine the molecular composition of the main paint constituents, High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS), to identify the type(s) of drying oils used as binders, and Gas Chromatography-Mass Spectrometry (GC-MS) using a recently developed analytical procedure that can discriminate and quantify free fatty and dicarboxylic acids, as well as their corresponding metal soaps (carboxylates of fatty and dicarboxylic acids). The results indicated that the addition of small amounts of additives can influence the water sensitivity of an oil paint, as well as its molecular composition. Additionally the nature of the ionomeric/polymeric network appears to be a significant determining factor in the development of water sensitivity.
20世纪，艺术家的颜料配方和技术有了重大发展，这可能与现代油画经常带来的新的保护挑战有关，包括不可预测的水敏感性和溶剂敏感性。本研究探讨了这类现代油画易损性背后的分子成因和机制。迄今为止的研究表明，水敏感性的出现与相对大量可提取的游离二元羧酸的存在之间存在关联。为了进一步探究这一点以及颜料配方的影响，对一组2006年用商业管状颜料制作的模型颜料样本进行了分析，这些样本中添加了已知量的添加剂。通过用水擦拭对样本进行水敏感性测试，并使用傅里叶变换红外光谱仪（FTIR）进行表征，以确定主要颜料成分的分子组成；使用高效液相色谱 - 质谱联用仪（HPLC - MS）来识别用作粘合剂的干性油的类型；使用气相色谱 - 质谱联用仪（GC - MS），采用一种最近开发的分析程序，该程序可以区分和量化游离脂肪酸和二元羧酸及其相应的金属皂（脂肪酸和二元羧酸的羧酸盐）。结果表明，添加少量添加剂会影响油画的水敏感性及其分子组成。此外，离聚物/聚合物网络的性质似乎是水敏感性发展的一个重要决定因素。
