Reversibly cross-linked polymer gels as healing agents for epoxy-amine thermosets.

The Diels-Alder reaction was used to develop a reversibly cross-linking gel as a healing agent for traditional epoxy-amine thermosets. Direct application of the reversibly cross-linking network to a crack surface in an epoxy-amine thermoset resulted in the recovery of 37% of the initial epoxy-amine network's strength. Composites in which the reversibly cross-linking gel was incorporated as a secondary particulate phase recovered 21% of the initial composite strength after the first healing cycle, with healing possible up to five times.