ELECTRO-CLEAVALBE EPOXY THERMOSETS: On-Demand Release, High Performance

An electrochemically cleavable epoxy is proposed as a reversible adhesive, suitable for a wide range of military and industrial applications. The Air Force currently needs to adhesively bond sub-miniaturized telemetry (SMT) and global positioning system (GPS) units to various locations on jet aircraft. The adhesive must rapidly bond to various substrates with a minimum of surface preparation. The bond must withstand the forces of Mach II flight and yet be removable without damaging the underlying surface. We propose combining the technology of electrochemically reversible disulfide polymerization/depolymerization with the proven abilities of amine cured epoxies, the work-horse resin of the adhesives industry. Epoxy resins will be synthesized with electrochemically cleavable disulfide bonds, which will be incorporated into the network polymer during cure. These linkages will remain quiescent until actively cleaved by the application of a reducing current at the bonded interface, effectively resulting in disbonding. This technique has advantages over chemical disbonding methods in that reaction occurs along the entire bonded interface. This non-corrosive procedure requires little or no added solvents, and allows recycling of spent material. In Phase I, epoxy adhesives will be developed, which are rapidly cleaved by passage of a low voltage current through the adhesive bond.