Permeability control in polymeric systems: a review

Controlling the extent of permeant (gas/vapour/liquid) transport through a polymer is critical in packaging applications. This can be achieved by changing the chemical and physical nature of the polymer, blending the polymer with another, dispersing particulate, fibrillar or lamellar fillers, converting the microstructure of the polymer to a cellular one, or using an effective combination of all of these processes. This review critically analyses different methods of controlling polymer permeability reported in literature. It provides recommendations and fresh approaches for modification of polymer permeability when considering large scale manufacturing of packages with controlled permeability properties. In addition, the subsequent effects of these modification techniques on the mechanical properties of the polymeric system are considered.