Kinetic Considerations for Strength Recovery at the Fiber–Matrix Interface Based on the Diels–Alder Reaction

The Diels-Alder reaction was used to yield thermal reversibility of the bonding between a partially furan-functionalized epoxy thermosetting matrix and a maleimide-treated glass fiber. Under ambient temperature conditions, the covalent bond forming product reaction dominates, but this reaction reverses at elevated temperatures to allow for interfacial healing. Single-fiber microdroplet pull-out testing was used to characterize the coupled effects of healing temperature and the glass transition temperature (T(g)) of the epoxy on interfacial strength recovery. In particular, the roles of mobility and reaction kinetics were independently varied to understand the individual effects of both.