Design of Experiments for the Effect of pH, Storage Time and Zinc Oxide Content on the Antibacterial Properties of Low-Density Polyethylene (LDPE)/Zinc Oxide Nanocomposites

The use of nanotechnology-based, active antibacterial materials in food packaging is of great importance for users health. Related to such potential use nanocomposite films containing 2.5%, 5%, 7.5% or 10% zinc oxide contents were melt mixed followed by blown film extrusion. Mechanical tests showed the best improvement in tensile strength and modulus for 5% loading. The effects of three factors, zinc oxide (ZnO) content, storage time and pH, on the antibacterial properties were investigated using response surface methodology (RSM). According to the results the analysis of variance by the RSM for the antibacterial properties of the low-density polyethylene ZnO nanocomposites followed a Quadratic model. The results showed that the maximum efficiency could be achieved at pH = 4.48. In addition, RSM showed the maximum antibacterial properties would be obtained for a reaction time of 5.5 days and zinc oxide content of 9.45%, which was near to the experimental value of 10%.