Baij Lambert, Hermans Joen J, Keune Katrien, Iedema Piet D
Van't Hoff Institute for Molecular Sciences, University of Amsterdam, PO Box 94157, 1090GD Amsterdam, The Netherlands.
Conservation and Restoration, Rijksmuseum Amsterdam, PO Box 74888, 1070DN Amsterdam, The Netherlands.
Macromolecules. 2018 Sep 25;51(18):7134-7144. doi: 10.1021/acs.macromol.8b00890. Epub 2018 Sep 7.
In the restoration of paintings, solvent diffusion and swelling of polymeric oil paint binding media are important factors to consider. Common cleaning methods with organic solvents or aqueous solutions could lead to undesirable physicochemical changes in the paint in the long term, though the extent of this effect is not yet clear. We used tailored nonporous model systems for aged oil paint to measure paint swelling and solvent diffusion for a wide range of relevant solvents. Using dynamic mechanical analysis (DMA), the glass transition temperature of our model systems was found to be close to room temperature. Subsequently, with a custom sample cell and time-dependent attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, we were able to accurately track swelling and diffusion processes in the polymer films. To quantify the spectroscopic data, we developed a model that completely describes the solvent migration process, including significant film swelling and non-Fickian solvent diffusion. The relation between solvent properties, the diffusion coefficient, and the swelling capacity proved to be rather complex and could not be explained using a single solvent parameter. However, it was found that strongly swelling solvents generally diffuse faster than weakly swelling solvents and that pigmentation does not significantly influence solvent diffusion. These results contribute to a better understanding of transport phenomena in paintings and support the development of improved paint restoration strategies.
在绘画修复中，聚合物油性涂料粘结介质的溶剂扩散和溶胀是需要考虑的重要因素。长期来看，使用有机溶剂或水溶液的常见清洁方法可能会导致涂料出现不良的物理化学变化，尽管这种影响的程度尚不清楚。我们使用定制的无孔老化油画模型系统，来测量多种相关溶剂在涂料中的溶胀和溶剂扩散情况。通过动态力学分析（DMA），我们发现模型系统的玻璃化转变温度接近室温。随后，利用定制的样品池和随时间变化的衰减全反射傅里叶变换红外（ATR-FTIR）光谱，我们能够准确跟踪聚合物薄膜中的溶胀和扩散过程。为了量化光谱数据，我们开发了一个模型，该模型完整地描述了溶剂迁移过程，包括显著的薄膜溶胀和非菲克型溶剂扩散。结果表明，溶剂性质、扩散系数和溶胀能力之间的关系相当复杂，无法用单一的溶剂参数来解释。然而，我们发现强溶胀溶剂通常比弱溶胀溶剂扩散得更快，而且颜料对溶剂扩散没有显著影响。这些结果有助于更好地理解绘画中的传输现象，并为改进绘画修复策略的开发提供支持。
