Toughening mechanisms and mechanical properties of graphene oxide/epoxy nanocomposites under tensile loading

Abstract

This study investigates the toughening mechanisms and mechanical behavior of graphene oxide (GO)/epoxy nanocomposites under tensile loading, providing insights into their failure mechanisms and performance optimization. GO/epoxy nanocomposites were fabricated with 0.25, 0.5, and 1 wt% GO incorporated into the epoxy matrix. Failure mechanisms were analyzed through fracture surface characterization using field-emission scanning electron microscopy, revealing key toughening mechanisms, including crack bowing, crack bridging, crack pinning, GO pull-out, and dimple/cusp formation. The study uniquely correlates these mechanisms with GO loading, demonstrating their role in enhancing fracture resistance and mechanical properties. Tensile testing showed that 0.5 wt% GO yielded optimal performance, with a 17.2% increase in Young's modulus and a 19.4% increase in tensile strength compared to neat epoxy, while higher loadings (1 wt%) led to agglomeration-induced performance degradation. These findings elucidate the interplay between GO dispersion, interfacial bonding, and fracture behavior, offering guidance for designing high-performance nanocomposites for aerospace, automotive, and biomedical applications.