Static and dynamic mechanical properties of epoxy nanocomposites reinforced by hybridization with carbon nanofibers and block ionomers

Epoxy (EP) is widely used in many engineering applications, however, its inherent brittleness limits their impact resistance. Conventional toughening agents usually lead to compromised compressive strength. In this study, a ternary composite with epoxy as matrix mixed with sulfonated polystyrene-block-poly (ethylene-co-butylene)-block-polystyrene (SSEBS) and functionalized carbon nanofibers (CNFs) was reported. The quasi-static and dynamic compression characteristics of EP/SSEBS/CNFs composites at different loading rates (0.003–3600 s⁻¹) are studied by means of a universal testing machine and split Hopkinson pressure bar (SHPB), respectively. The results show that the Young's modulus, yield strength, compressive strength and failure strain of EP/SSEBS/CNFs composites with 0.75 wt% CNFs are all higher than those of EP at high strain rates. Among them, at a strain rate of 3600 s⁻¹, the increase of Young's modulus and compressive strength reaches 57% and 195.5%, respectively. Compared with EP, EP/SSEBS/CNFs composites exhibits more significant strain rate effect and strain hardening effect. Moreover, the large deformation ability of SSEBS, the bridging effect of CNF and the excellent interfacial properties between the hybrids and the EP matrix are found to be the main reasons for realizing the reinforcement and toughening of EP composites.