Viana Carolina, Wieland Karin, França de Sá Susana, Angelin Eva Mariasole, Pintus Valentina, Ferreira Joana Lia
LAQV-REQUIMTE, Department of Conservation and Restoration, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
Competence Center CHASE GmbH, Ghegastrasse 3, A-1030 Vienna, Austria.
Polymers (Basel). 2024 Oct 8;16(19):2841. doi: 10.3390/polym16192841.
Vinyl acetate (VAc)-based emulsions represent one of the main media used by modern and contemporary artists. Their long-term behaviour is still not completely understood, especially due to the scarce knowledge on the influence of other compounds in the formulation, which may impact ageing over time. Besides the polymer backbone based on vinyl acetate, other co-monomers and additives can be added to the emulsion to alter the final film's physical, chemical, and optical properties. By extension, the formulation will also impact the long-term stability of artworks and objects on which it has been applied, as well as possible current and future conservation interventions such as cleaning. For those reasons, studies shedding light on the correlation between composition and long-term stability are largely necessary. In this study, different emulsions, including homopolymers, copolymers, plasticised, and un-plasticised compositions, were gathered and artificially aged. A multivariate analyses approach based on the application of principal component analyses (PCA) and hierarchical cluster analyses (HCA) was employed for the first time on the combination of data obtained by pH, contact angle (CA), colour measurements, Fourier transform infrared spectroscopy in attenuated total reflection (FTIR-ATR), and size exclusion chromatography (SEC). This approach helped to highlight the changes that occurred during ageing and find correlations with the formulation compositions. The results further sustain the thesis that not all vinyl acetate-based emulsions are chemically the same and that their formulation deeply impacts their long-term behaviour.
醋酸乙烯酯（VAc）基乳液是现代和当代艺术家使用的主要媒介之一。其长期性能仍未被完全理解，尤其是由于对配方中其他化合物影响的了解不足，这些化合物可能会随着时间影响老化过程。除了基于醋酸乙烯酯的聚合物主链外，还可以向乳液中添加其他共聚单体和添加剂，以改变最终薄膜的物理、化学和光学性能。进而，配方也会影响其所应用的艺术品和物品的长期稳定性，以及当前和未来可能的保护干预措施，如清洁。出于这些原因，深入研究成分与长期稳定性之间的相关性非常必要。在本研究中，收集了不同的乳液，包括均聚物、共聚物、增塑和未增塑的组合物，并进行人工老化处理。首次采用基于主成分分析（PCA）和层次聚类分析（HCA）的多变量分析方法，对通过pH值、接触角（CA）、颜色测量、衰减全反射傅里叶变换红外光谱（FTIR-ATR）和尺寸排阻色谱（SEC）获得的数据进行综合分析。这种方法有助于突出老化过程中发生的变化，并找出与配方组成的相关性。结果进一步支持了这样的论点，即并非所有醋酸乙烯酯基乳液在化学性质上都是相同的，其配方对其长期性能有深远影响。
