In this work, the effects of as-produced GO and silane functionalized GO (silane-f-GO) loading and silane
functionalization on the mechanical properties of epoxy composites are investigated and compared. Such
silane functionalization containing epoxy ended-groups is found to effectively improve the compatibility
between the silane-f-GO and the epoxy matrix. Increased storage modulus, glass transition temperature,
thermal stability, tensile and flexural properties and fracture toughness of epoxy composites filled with
the silane-f-GO sheets are observed compared with those of the neat epoxy and GO/epoxy composites.
These findings confirm the improved dispersion and interfacial interaction in the composites arising from
covalent bonds between the silane-f-GO and the epoxy matrix. Moreover, several possible fracture
mechanisms, i.e. crack pinning/deflection, crack bridging, and matrix plastic deformation initiated by
the debonding/delamination of GO sheets, were identified and evaluated.