Synergistic effect of cellulose nanocrystals/graphene oxide nanosheets as functional hybrid nanofiller for enhancing properties of PVA nanocomposites

• Cellulose nanocrystals (CNC) and graphene oxide (GON) were combined to get a novel hybrid nanofiller.
• 3D network microstructure was formed by the combination of CNC and GON two kinds of nanomaterials.
• Hybrid nanofiller was used to enhance the tensile properties of PVA nanocomposites.
• Large increase of tensile properties of PVA was observed due to the synergistic effect.

Novel functional hybrid nanofillers composed of cellulose nanocrystals (CNC) and graphene oxide nanosheets (GON), at different weight ratios (2:1, 1:1 and 1:2), were successfully prepared and characterized, and their synergistic effect in enhancing the properties of poly(vinyl alcohol) (PVA) nanocomposites was investigated. Due to the synergistic reinforcement, it was found that the Young's modulus, tensile strength and toughness of the PVA nanocomposite containing 5 wt% hybrid nanofiller (1:2) were significantly improved by 320%, 124% and 159%, respectively; and the elongation at break basically remained compared to the neat PVA matrix. In addition, the glass and melting temperatures as well as the moisture sorption of nanocomposites were also enhanced. This synergistic effect improved the dispersion homogeneity by avoiding the agglomeration phenomenon of nanofillers within the polymer matrix, resulting in nanocomposites with largely enhanced properties compared to those prepared from single nanofiller (CNC or GON). The preparation of these hybrid nanofillers and their incorporation into a polymer provided a novel method for the development of novel multifunctional nanocomposites based on the combination of existing nanomaterials.