Room temperature self-healable epoxy elastomer with reversible alkoxyamines as crosslinkages

To provide room temperature self-healing ability to crosslinked epoxy elastomer, alkoxyamine-based diglycidyl ether (DiEPO) is synthesized and cured with polythiol. The C–ON bonds in both the alkoxyamine monomer and the cured epoxy are able to be synchronously cleft and recombined, achieving a dynamic reversible equilibrium state. This habit can thus be used as a healing chemistry for repeatedly re-bonding cracked polymer. Moreover, because the nitrile group that possesses strong capability of adsorbing electrons is attached to the carbon atom of C–ON bonds, homolysis temperature of the alkoxyamine is greatly reduced. The reversible reaction becomes oxygen insensitive in the meantime. As a result, multiple self-healing of the epoxy elastomer in air without manual intervention (heating) is observed by visual inspection and tensile test. Compared to the self-healing crosslinked polymers containing alkoxyamine moieties, which were previously developed in our lab and had to operate at elevated temperature in argon, the current work represents an interesting progress towards practical application in this aspect.