Permeation
Permeation
The process by which chemicals slowly pass through container walls at a molecular level.
Permeation is the process by which molecules of a stored substance migrate through the container wall material at a molecular level. While HDPE has excellent barrier properties for most substances, certain chemicals — particularly aromatic solvents, chlorinated hydrocarbons, and essential oils — can permeate through HDPE over time. Permeation rate depends on wall thickness, temperature, chemical concentration, and the specific chemical-plastic interaction. Fluorination treatments can reduce HDPE permeation by up to 99%.