Starch-PVA Nanocomposite Film Incorporated with Cellulose Nanocrystals and MMT: A Comparative Study

The goal of this work was to compare the barrier, mechanical, and thermal properties of two types of starch-polyvinyl alcohol (PVA) nanocomposites. Sodium montmorillonite (MMT) and nanocrystalline cellulose were chosen as nanoreinforcements. X-ray diffraction (XRD) test showed well-distributed MMT in the starch-PVA matrix, possibly implying that the clay nano-layers formed an exfoliated structure. The moisture sorption, solubility and water vapor permeability (WVP) studies revealed that the addition of MMT and nanocrystalline cellulose reduced the moisture affinity of starch-PVA biocomposite. At the level of 7% MMT, the nanocomposite films showed the highest ultimate tensile strength (UTS) (4.93 MPa) and the lowest strain to break (SB) (57.65 %). The differential scanning calorimetry (DSC) results showed an improvement in thermal properties for the starch-PVA-MMT nanocomposites, but not for the starch-PVA-NCC nanocomposites. Results of this study demonstrated that the use of MMT in the fabrication of starch-PVA nanocomposites is more favorable than that of nanocrystalline cellulose to produce a desirable biodegradable film for food packaging applications.