Simultaneous Strengthening and Toughening of Epoxy via a Silicone Polymer–Graphene Oxide Hybrid Nanofiller

ABSTRACT Achieving simultaneous improvement in strength and toughness of epoxy resins remains challenging due to the intrinsic trade‐off between rigidity and ductility. In this study, a hybrid nanofiller composed of silicon polymer (PSOL) and graphene oxide (GO) was prepared via a reflux‐assisted modification strategy and incorporated into an epoxy (EP) matrix. The incorporation of PSOL/GO improves the filler dispersion state and interfacial compatibility in the epoxy matrix, contributing to synergistic mechanical enhancement. Mechanical evaluation shows that the PSOL/GO hybrid outperforms the corresponding single‐component modifications. The 1PSOL/0.2GO/EP composite exhibits a tensile strength of 63.84 MPa, representing an increase of 37.91% compared with neat EP, while 2PSOL/0.2GO/EP reaches a maximum impact strength of 4.49 kJ m −2 , corresponding to an increase of 39.44%. Morphological and thermomechanical analyses further indicate that the enhanced performance is associated with improved filler dispersion, enhanced interfacial compatibility, crack deflection, and energy dissipation during fracture. This work offers an effective route to address the strength–toughness trade‐off in epoxy systems and provides guidance for the design of high‐performance polymer composites based on hybrid nanofillers.