▎ 摘　　要

Uniform dispersion of nanoplatelets in a polymer matrix is always a great concern in the production of high quality nanocomposites. Graphene oxide (GO) was synthesized by Hummer's method in a unique way that improved nanoclay dispersion in casting polyvinyl alcohol (PVA) film. Montmorillonite (MMT)-GO/PVA nanocomposites were synthesized by solution-casting method. The addition of a small amount (e.g., 0.25% by wt) of graphene oxide greatly improved nanoclay dispersion and significantly enhanced the mechanical properties of PVA hybrid nanocomposite. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) imaging proved that montmorillonite layers and graphene oxide (GO) sheets were uniformly dispersed in the polymeric matrix and favorably oriented parallel to the surface. X-ray diffraction (XRD) showed that both nanoplatelets were thoroughly exfoliated and uniformly distributed on the surface of nanocomposite films. Differential scanning calorimetry (DSC) indicated a slight degree of PVA crystallinity. While there was a significant improvement in the mechanical properties of the films, for the PVA film with 2.5% (by wt) montmorillonite and 0.25% (by wt) graphene oxide, the advanced mechanical properties were evidence of the synergy of the two nanoplatelets under favorable conditions. Graphic abstract