High strain rate behavior of polycaprolactone reinforced with aramid nanofiber for insight into dynamic behavior

Self-healing materials are repairable and extend product lifetimes but are limited in application due to their mechanical properties such as low yield strength. Here, we examined the dynamic mechanical performance of an elastomeric polymer composite containing aramid nanofibers. These studies provided an economically feasible foundation to understand the reinforcement concentration and resultant mechanical properties that would result should aramid nanofibers be used to reinforce a self-healing polymer that requires complex synthesis methods and expensive reactants. The elastomeric polymer used was polycaprolactone containing various weight percent aramid nanofibers. Dynamic mechanical testing of these samples was performed using a split-Hopkinson pressure bar system that enabled quantification of polymer softening and aramid nanofiber reinforcement. Dynamic flow stress and strain rates were also calculated with these data. Crystallinity and thermal softening effects of solvent dissolution of polycaprolactone are explored to further characterize the performance of aramid nanofibers as a fiber in composite materials.