Barrier properties of polyethylene refer to no or only minimal permeability to gases (e.g., oxygen, carbon dioxide, nitrogen), vapors (e.g., water vapor), and aromas. Low permeability values also indicate good barrier properties.
The oxygen permeability of polyethylene (PE) varies depending on the type of polyethylene and other factors such as thickness and processing conditions. In general, polyethylene is a type of plastic with relatively low oxygen permeability, especially compared to some other plastics.
HDPE (High Density Polyethylene) generally has a lower oxygen permeability than LDPE (Low Density Polyethylene). This is because HDPE has a denser molecular structure, which helps reduce the passage of gases such as oxygen.
The oxygen permeability of PE can also be influenced by factors such as the use of barrier layers, special coatings, or other treatments. In some applications, particularly food packaging, it may be necessary to further reduce oxygen permeability to improve product shelf life and freshness.
It is important to note that the oxygen permeability of PE can vary depending on the specific application and requirements. Therefore, additional measures may be necessary to ensure the packaging provides the desired protection.
Depending on the film thickness, the following oxygen permeability values can be achieved:
PE-LD films have low water vapor permeability and relatively high oxygen permeability.
The oxygen permeability of packaging films is usually measured on a flat film at a defined point at a temperature of around 23 ºC. The measuring method (DIN 53380-3) is standardized and very complex.
