(296e) Evaluation of 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. It was found that the relationship between T – T_g and healing efficiency is linear with a positive slope when testing occurs under ambient conditions. However, when testing occurs at elevated temperatures, the behavior deviates significantly and the relationship between T – T_g and healing efficiency is negatively linear. Combining this with the relationship between mobility and bond formation, a model to describe bond formation at the glass-polymer interface can begin to be described.