▎ 摘　　要

The influence of seawater aging on the flexural and thermomechanical properties of glass fiber/epoxy (GF/E) composites containing the hybrid combination of multiwall carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) was experimentally investigated in this work. The three-point bending and dynamic mechanical analysis were performed to test flexural modulus, flexural strength, strain to failure, storage modulus, and glass transition temperature (T-g) of hybrid MWCNT/GNP-GF/E composites at different mixing ratios (1:0, 7:1, 3:1, and 0:1) which were immersed in seawater at 60 degrees C. The results confirm that seawater aging plays a significant role in reducing the mechanical and thermomechanical properties of hierarchical composite laminates due to degradation and weakening of the fiber/matrix interface as a consequence of plasticization and swelling effects of the polymer matrix. Despite this serious physical degradation, MWCNT/GNP-GF/E hybrid composites with (7:1) showed a better resistance to seawater aging, with slight improvements in flexural strength (2%), strain to failure (14%), and T-g (12%) compared to neat GF/E composites, due to positive synergistic effect of the carbon nanostructures in the composite laminates, making them suitable for marine applications.