Facile Fabrication of Fast Recyclable and Multiple Self-healing Epoxy Materials through Diels-Alder Adduct Cross-linker

A reversibly cross-linked epoxy resin with efficient reprocessing and intrinsic self-healing was prepared from a diamine Diels-Alder (DA) adduct cross-linker and a commercial epoxy oligomer. The newly synthesized diamine cross-linker, comprising a DA adduct of furan and maleimide moieties, can cure epoxy monomer/oligomer with thermal reversibility. The reversible transition between cross-linked state and linear architecture endows the cured epoxy with rapid recyclability and repeated healability. The reversibly cross-linked epoxy fundamentally behaves as typical thermosets at ambient conditions yet can be fast reprocessed at elevated temperature like thermoplastics. As a potential reversible adhesive, the epoxy polymer with adhesive strength values about 3 MPa showed full recovery after repeated fracture-thermal healing processes. The methodology explored in this contribution provides new insights in modification of conventional engineering plastics as functional materials. (C) 2015 Wiley Periodicals, Inc.