Fluid Compatibility Testing of Polymers

All polymers interact to a degree with fluids (liquids, gases), physico-chemically (i.e., swelling) and/or chemically (i.e., irreversible change). The extent of swelling depends primarily on the chemical similarity of the fluid and the polymer - “like swells like”. For instance, the all-hydrocarbon elastomer EPDM is swollen significantly by aliphatic hydrocarbon liquids, but negligibly by water. The oil resistance of nitrile elastomers increases with acrylonitrile content of the base polymer, as does glass transition temperature.