Preparation and Study of the Mechanical Properties of CTBN /n‐ CeO 2 Synergistically Modified With Epoxy‐Based Glass Fiber Composites

ABSTRACT Glass fiber‐reinforced polymer (GFRP) composites are widely utilized across various industries due to their high specific strength and cost‐effectiveness. However, their structural reliability under complex loading is fundamentally limited by the inherent brittleness of the epoxy resin matrix and weak interfacial bonding, which often precipitate premature interlaminar delamination. To overcome these limitations, this study proposes a multi‐scale synergistic toughening strategy using carboxyl‐terminated butadiene‐acrylonitrile (CTBN) rubber and nano‐cerium dioxide (n‐CeO 2 ). High‐performance laminates were fabricated via vacuum‐assisted resin transfer molding (VARTM). Mechanical evaluations demonstrate that the optimal multi‐scale formulation (GF‐04) significantly outperforms the unmodified reference, exhibiting flexural, compressive, and tensile strengths of 631.85 MPa (increases of 65%), 341.90 MPa (increases of 75%), and 461.59 MPa (increases of 58%), respectively. Under low‐velocity impacts of 20 and 40 J, the maximum impact loads increased by 12% (4.97 kN) and 18% (5.64 kN), yielding a remarkable 38% enhancement in compression after impact (CAI) residual compressive strength (calculated and reported strictly according to ASTM D7137), corresponding to a peak collapse load of 10.78 kN for the 40 J condition. Microstructural analysis confirms homogeneous phase dispersion and reveals that the synergistic interplay between CTBN‐driven plastic dissipation and n‐CeO 2 ‐enhanced stress transfer successfully shifts the failure mode from brittle cleavage to ductile fracture. This work elucidates the micro‐mechanisms of organic–inorganic hybrid toughening, offering a viable engineering pathway for developing advanced composites with superior strength, toughness, and damage tolerance.