Synergistic Effect of Halloysite and Cellulose Nanocrystals on the Functional Properties of PVA Based Nanocomposites

Poly(vinyl alcohol) (PVA) based nanocomposites filled with different amounts of halloysites (HNTs) and/or cellulose nanocrystals (CNC) were produced and characterized in terms of mechanical and barrier properties, thermal stability, and transparency. A significant increase in tensile strength by more than 70% and an unexpected improvement in elongation at break were observed for all the PVA nanocomposites when compared to the pristine PVA. Moreover, the presence of both CNC and HNTs at the highest loadings of 5 and 3 wt %, respectively, improved the thermal stability of the PVA matrix and reduced its water vapor permeability (WVP) by more than 42%. All the developed PVA nanocomposites maintained their transparency due to the good and homogeneous dispersion of both the nanofillers in the PVA matrix. Results highlight the synergistic effect of HNT and CNC on the barrier and mechanical properties of PVA, mainly due to the establishment of specific interactions between the OH groups of HNT and CNC particles.