Mersedeh Jorjani, George Wheeler, Carolyn Riccardelli, Winston O. Soboyejo, and Nima Rahbar
A collaboration among conservators, conservation scientists, and material scientists has yielded interesting results in evaluating adhesives for the reassembly of marble fragments. Understanding the properties of adhesives in this context is essential for their optimal use. Two such properties – interfacial fracture toughness and bond line width – were examined. This project aims to aid conservators in making informed decisions in choosing adhesives by comparing the performance of thermoplastic and thermosetting resins commonly used in marble repair. The interfacial fracture toughness of Brazil-nut specimens is determined using tensile splitting tests. The following eight adhesive systems were used: Paraloid B-72, Paraloid B-48N, a 3:1 mix of Paraloid B-72 and B-48N, Hxtal NYL-1, Epotek 301-2, Akepox 2000, Marmorkitt 1000, and a Paraloid B-72/Epotek 301-2 sandwich.
One hypothesis tested in this study is that thermoplastic resins could be used as structural adhesives for marble repair. The goal of using such adhesives is to provide reversibility while maintaining adequate strength of the joint. Results indicate that from the perspective of interfacial toughness, several thermoplastic systems are viable for marble repair.
Another important property, adhesive bond width, is also determined. For each adhesive, the bond width is compared to values previously published in conservation literature. These data are then used to assess the correlation between bond widths and interfacial toughness of the various adhesives.