Influence of Beeswax Content on Barrier Properties of PVA-Based Films

The aim of this study was to establish the optimal content of beeswax (BW) that can be added to a polyvinyl alcohol (PVA) matrix in order to obtain the maximum barrier effect against water vapor. The beeswax, ranging from 0 wt.% to 17.79 wt.%, induced surface heterogeneity and increased roughness. Although migration in all the studied simulants exceeded the limit of 10 mg/dm2/24 h, of all the prepared films, the most efficient ones were found to be those containing 12.63–15.5 wt.% beeswax, which exhibited 50% lower solubility in aqueous, acidic, alcoholic, and fatty food simulants than did neat PVA. The disadvantage is that the tensile strength of the films is 16 times less than PE and 8 times less than unchanged PVA when 12.63–17.79 wt.% BW is added. The water vapor transmission rate was 24 times lower than that of neat PVA and only 2 times higher than that of polyethylene (PE). Additionally, the results confirmed the separation of PVA and beeswax phases with the addition of more than 15.5 wt.% beeswax. BW incorporation modifies the high-temperature degradation pathway of PVA, leading to more substantial mass losses, but without compromising the overall thermal stability of the films. This is a preliminary study that established that the maximum hydrophobic effect is obtained at a beeswax content of 15.29 wt%. The preparation recipe must be optimized by testing with other hydrophobic agents that reduce migration in simulants and increase the barrier properties, and nanoparticles that increase mechanical strength.