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.