Barrier Properties of PVA/TiO_2/MMT Mixed-Matrix Membranes for Food Packaging

摘要

One of the important challenges in food industries is to achieve sufficient gas barrier properties for packaging films. Films made of polyvinyl alcohol (PVA) are commonly used for food packaging and are sometimes used with embedded nanoparticles. In this investigation, PVA nanocomposite films were prepared using solution-casting method with different concentrations of montmorillonite (MMT) and titanium oxide (TiO2) nanoparticles. A response surface methodology (RSM), based on three-level factorial design, was implemented to model and optimize the effect of the concentrations of the nanofillers on the barrier properties of thin nanocomposite films. The viscosity of the polymer-forming solution increased when nanoparticles were incorporated in the polymer matrix. SEM micrographs showed a good distribution of nanofillers at low concentration whereas some aggregation was observed at higher nanofiller loadings. Transparency of PVA-based thin films decreased with an increase of TiO2/MMT loading. A significant increase in the Young's modulus occurred with an increase in the loading of nanoparticles whereas the tensile strength and elongation at the breakpoint both decreased. Results for PVA/MMT/TiO2 nanocomposite films showed a decrease in the oxygen transmission rate and water vapor permeability compared to a neat PVA membrane. The particle loading leading to optimum barrier properties for nanocomposite films was a combined loading of 1 wt% TiO2 and 4 wt% MMT.[GRAPHICS].