Microstructure of High-Barrier Film for Dairy Packaging

High-filled, or high-barrier packaging materials are a promising direction of dairy packaging. These films provide safety, quality, and operational stability. In addition, they require no sophisticated equipment for recycling. Mineral calcium carbonate remains the most popular inorganic chemical filler. However, mineral-filled polymer compositions are understudied from the perspective of their structure and properties. These properties depend on the polymer base (binder), the mineral filler, its grinding, the technology of combining in the melt during extrusion, the dispersion of the filler in uncertain environment, etc. By studying the effect of filler concentration on the microstructure of polyethylene film samples, one can assess the dispersion of calcium carbonate in the polymer to reveal the processes behind the changes in the physical and mechanical properties of films. A series of previous studies featured a polyethylene film filled with 20–70% calcium carbonate. In this research, dihydroquercetin in concentrations of 0.5 and 1.0% served as an additional modifying component with antioxidant properties. The film samples were visually homogeneous. The method of scanning electron microscopy indicates a relatively uniform distribution of filler particles (50 wt%). The samples with 70 wt% showed a rather loose and uneven distribution of particles under the X-ray spectroscopy. The micrographs revealed crystalline particles of dihydroquercetin diffusing onto the surface of the packaging material.