Temperature Dependency
Mathematical models for mass transfer use a temperature-dependent rate to describe how quickly molecules travel through a polymer matrix. The arrhenius diffusion coefficient relates the rate of molecular movement to thermal energy. This relationship explains why transport through polymer barriers accelerates as the ambient temperature rises.
Barrier Calculation
Barrier properties of flexible packaging films are evaluated by calculating transport rates under varying climatic conditions. Using the arrhenius diffusion coefficient, engineers predict the shelf life of food products by determining the rate of oxygen or water vapor entry at elevated temperatures. The calculation relies on a pre-exponential factor and the activation energy of diffusion.
High-density polyethylene, for example, shows predictable changes in barrier performance across seasonal shifts when these values are known.
Migration Behavior
Packaging safety compliance demands accurate prediction of how monomers and additives migrate from plastic films into food simulants. The arrhenius diffusion coefficient governs the speed of these chemical substances moving through the packaging layers over time. Under typical storage conditions, low molecular weight molecules remain relatively locked within the polymer grid.
Once the film is heated, as in microwave or boiling applications, the transport rate climbs dramatically. Understanding this behavior allows converters to select specific polymers that maintain low migration even under high-heat treatments.
