Design of Debonding Epoxy Adhesives Based on Photo- and Thermoresponsive Dynamic Networks

Epoxy adhesives have found extensive application in the fields of aerospace, automotive, and electronics industries due to their excellent mechanical properties, bond strength, and thermal stability. However, the cured epoxy adhesive forms three-dimensional (3D) cross-linked networks, which makes debonding challenging and cannot meet the requirements of temporary positioning, recycling, and reuse of precision parts particularly in the electronic devices area. The incorporation of dynamic networks into adhesives is an effective approach to achieving debonding. In this study, a series of anthracene-modified debonding epoxy adhesives were successfully synthesized using anthracene-9-ylmethyl 3-mercaptopropanoate (ANSH) and N,N-diglycidyl-4-glycidyloxyaniline (AFG-90H) by epoxy–thiol “click reaction” under Et3N conditions. The adhesive undergoes a synergistic curing process involving a [4π + 4π] cycloaddition reaction and epoxy self-curing under light and heat conditions (365 nm UV-light irradiation and 65 °C), resulting in optimal bonding with an excellent shear strength of 2.01 ± 0.14 MPa. Moreover, it is capable of breaking the covalent bonds of the anthracene dimers at milder heat stimulation (120 °C), with a debonding rate of up to 87%. The findings offer a promising avenue for the development of a debonding epoxy adhesive.