Chemistry and Heritage Conservation: Calcium-Based Mineralized Hydrogel for the Adhesive Restoration of Historical Artifacts

Chemistry and cultural heritage conservation are inextricably linked. Preserving historical artifacts is a challenging task that requires an understanding of chemistry. Combining the conservation of historical artifacts with chemical experimental teaching, a calcium tannate mineralized hydrogel (TA-Ca/Gel) was designed to be applied as an adhesive to restore historical artifacts for undergraduate college students. Acrylic acid (AA), acrylamide (AM), and N,N′-methylenebis(acrylamide) (MBAA) were used to construct the network of the hydrogel, while tannic acid (TA) and Ca(OH)2 served as the mineralization and adhesion-enhancing components. Tetramethylenediamine (TMEDA) served as the gel accelerator. The structural and morphological characterization of TA-Ca/Gel was performed with the assistance of technicians from the School Analysis and Testing Center. Students plotted and analyzed the characterization data using Origin software. The adhesive properties of TA-Ca/Gel were measured by a universal tensile tester. Finally, TA-Ca/Gel was used as an adhesive to repair broken porcelain and pottery. We have received positive feedback from the students through this comprehensive chemical experiment, which helped students obtain a better understanding of how to synthesize and characterize the mineralized hydrogel, how to analyze the test data, and how to present data from drawing software. This also introduced them to the study of basic principles of historical artifact protection as well as the relationship between chemistry and heritage conservation. Inspired by the topic of "Chemistry and heritage conservation", we deepened students' understanding of the application of comprehensive and cutting-edge knowledge.