The Interaction Effects of Montmorillonite and Glycerol on the Properties of Polyvinyl Alcohol-montmorillonite Films

Background and Objectives: Preparation and evaluation of nanocomposite films have become prevalent in recent years. Depending on the purpose of using the film, and considering the effects and interaction effects of nanomaterial and other modifiers on the film properties, the amounts of nanomaterials and modifiers should be optimized. The effects of montmorillonite (MMT), glycerol (GL), and their interaction effects on the properties of polyvinyl alcohol-montmorillonite (PVA-MMT) films were evaluated in this research. Materials and Methods: PVA-MMT films were produced based on a full factorial experiment in a completely randomized design (CRD) with 16 treatments and three replicates. There were two factors with four levels: MMT (0, 5, 12, and 20% weight per weight of polymer W/WP), and GL (0, 10, 30, and 50% W/WP). The films were characterized by mechanical properties, opacity, water vapor permeability (WVP), and color. Results: MMT increased tensile strength (TS), b*, yellowness index (YI), and opacity of the films. MMT, however, reduced elongation (E%) and WVP of the films. The effect of GL on the films was quite opposite the MMT. In addition, the interaction effects of MMT-GL on WVP, YI, and b* were significant (p<0.01). MMT contents could reduce WVP just in the presence of GL in the films, while GL contents could increase WVP at all MMT concentrations. Furthermore, MMT contents could increase YI of the films at all GL concentrations, while GL could increase YI just at 20% MMT content. Strong affinities of MMT, and GL with PVA were proved by FTIR. Conclusions: Considering the target of utilizing PVA-MMT films, appropriate concentrations of MMT, GL, and their proper combination should be selected.