Technological Educational Institute of Athens, Department of Conservation of Antiquities & Works of Art, Egaleo 12210, Greece.
Appl Spectrosc. 2012 May;66(5):580-90. doi: 10.1366/11-06371.
An ethylene-methacrylic acid copolymer, formulated by BASF as a waterborne suspension of its alkylammonium salt and used, among other applications, in art conservation as a temporary protective coating was characterized using Fourier transform infrared (FT-IR) spectroscopy aided by modulated differential scanning calorimetry (MDSC) and ellipsometry. The thermal conversion of thin copolymer films from the freshly applied state, where carboxylic acid and carboxylate ion functional groups co-exist, to a purely acidic working state was spectroscopically followed. Transmission mid-infrared data of the working state showed a 1 : 12 ratio of methacrylic acid towards ethylene units. The glass transition temperature (T(g)) in the same state was found at 45 °C. Copolymer films spin-coated on mechanically polished bronze and iron coupons were characterized with transflection infrared spectroscopy and compared to corresponding transmission mid-infrared spectra of copolymer films spin-coated on silicon wafers. In the case of bronze coupons, evidence for interaction of the carboxylate ion with the copper substrate was obtained. The chemical structure and the thermal behavior of the coating, as well as some implications on its protective capability towards iron and copper alloys, is discussed as this material has received considerable attention in the field of metal conservation and coatings.
一种乙烯-甲基丙烯酸共聚物，由巴斯夫（BASF）作为其烷基铵盐的水分散体进行配方设计，除其他应用外，还在艺术保护中用作临时保护涂层，使用傅里叶变换红外（FT-IR）光谱法辅以调制差示扫描量热法（MDSC）和椭圆光度法进行了表征。通过光谱法跟踪了从新施加状态（羧酸和羧酸根离子官能团共存）到纯酸性工作状态的薄共聚物膜的热转化。工作状态的透射中红外数据显示，甲基丙烯酸与乙烯单元的比例为 1：12。在相同状态下的玻璃化转变温度（T(g)）为 45°C。通过反射红外光谱对机械抛光青铜和铁试片上旋涂的共聚物膜进行了表征，并与旋涂在硅片上的共聚物膜的相应透射中红外光谱进行了比较。在青铜试片的情况下，获得了羧酸根离子与铜基底相互作用的证据。讨论了涂层的化学结构和热行为，以及其对铁和铜合金的保护能力的一些影响，因为这种材料在金属保护和涂层领域受到了相当多的关注。
