Magnetocuring of temperature failsafe epoxy adhesives

Adhesive technology is of high and increasing interest in a wide variety of conventional and emerging applications. One-component adhesives typically cure using moisture, heat and light. These approaches limit applications to specific substrates, inefficient handling in manufacturing, and can only be indirectly activated. Hence, we developed a method for remote, wireless, contactless curing of adhesives using alternating magnetic fields (AMF). This approach (“magnetocuring”) offers energy efficient, on-demand adhesion. Exposure of Mn_xZn_1-xFe₂O₄ Curie temperature tuned magnetic nanoparticles (CNP) additives within commercial epoxy adhesives to an AMF cured thermoset resins within min with minimal rise in substrate temperature. The heating of the CNP “switches off” above its Curie temperature offering failsafe heating. The in-situ heating of the CNP can be controlled by CNP composition, CNP loading, and AMF strength. Internal temperatures of 160 °C could be reached in 5 min, allowing curing of most commercial epoxy adhesives without resin scorching. The maximum lap shear adhesion strength exceeded 6.5 MPa. Magnetocuring is demonstrated on wood, ceramics, and plastics, which is of considerable interest in sports, automotive, and aerospace industries.