Epoxy adhesives are commonly used by art conservators to repair, strengthen, and reconstruct ceramic and glass artifacts.  They are desirable because of their high strength, optical clarity, and low shrinkage during cure.  One of the most important concepts in art conservation is that of treatment reversibility to avoid improper reconstruction or damage caused by the treatment itself.  Unfortunately, cured epoxies are intractable due to extensive crosslinking.  We have therefore tailored an epoxy which is thermally reversible from a strong solid to a viscous liquid upon heating above 90 �C.  The purpose of this project is to study the chemical, mechanical, and working properties of the thermally reversible epoxy adhesive in relation to its use on artifacts.  Our approach to reversibility was to incorporate thermal Diels-Alder weak links into a siloxane-bridged epoxy resin, and to optimize the curing properties using four commercial hardeners.  This was accomplished by synthesizing the epoxy component of the adhesive with maleimide-furan cycloadducts between glycidal groups.   By placing a siloxane bridging group in the epoxy component, we were able raise the melting point sufficiently to afford a liquid epoxy precursor that was easily mixed with liquid amine terminated polyethers.  The cured epoxy was tested for mechanical tensile strength using an MTS Criterion Electromechanical testing system and the ASTM D1002-10 standard.  Chemical properties of the epoxies were fully characterized via NMR, ATR�FTIR spectroscopy, HR-MS spectroscopy, TGA, and MDSC analysis.  The thermally reversible epoxy was successfully applied to and removed from glass and ceramic artifacts at the Arizona State Museum, demonstrating a new tool to aide conservators in preservation and repair of important artifacts.

Thermally re-workable epoxy adhesives for use in artifact repair

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.