Reproducing reality. Recreating bonding defects observed in transparent poly(methyl methacrylate) museum objects and assessing defect formation

The most common method chosen by artists, designers, and craftsmen to realize artworks and objects with transparent poly(methyl methacrylate) (PMMA) is to bond pieces from premanufactured sheets using solvents or adhesives. This method is considered relatively easy to use, however achieving bonds that are both transparent and strong can be difficult. Artifacts from museum collections made by bonding transparent PMMA often exhibit a variety of bonding defects and failures not yet addressed in depth in the conservation literature. Therefore, an international project started with the aims of classifying these bonding issues and understand their causes. This paper presents the results of the first part of this project which included the following research activities: surveys of bonding defects in PMMA artworks and design objects in museum collections, a literature review of the most recommended materials and methods used to bond PMMA over time, the preparation of bonded PMMA mock-ups based on literature review, chemical characterization of the bonding materials, thermal ageing of mock-ups, and finally technical examinations of the PMMA bonded mock-ups. The main defects observed in the museum objects surveyed were successfully recreated in the lab and the causes of their formation were assessed.