EPDM is a synthetic rubber which is custom molded for this application. The compound formulation and molding technique are critical to ensure that the membrane maintains its physical properties over a long period of time, resists tearing, retains its shape even after years of continuous or cyclical use, and produces fine bubbles, all at a minimal head pressure. Our EPDM membranes are field tested in municipal and industrial applications with excellent results. However, standard EPDM is not recommended in cases where solvents, fats oils or greases, or high concentrations of other foulants are present.

PTFE belong to a category of synthetic rubbers called Fluoroelastomers. They are considered high performance due to their broad spectrum resistance to chemicals, solvents, fats, greases, etc… which can damage conventional elastomers. They are, however, quite expensive. SSI pioneered and patented the use of thin film surface layers of Fluoroelastomers permanently joined to the surface of an EPDM or other substrate base material through patented and now proven methods. The benefit of SSI's advanced technology is that you can have the affordable cost and proven physical properties of a conventional elastomer with the chemical, solvent and fat resistance of the most advanced elastomers in the world. SSI has proven in plants where, for example, calcium deposits and solvent exposure previously caused other materials to fail rapidly, our fluoroelastomer layered membranes are performing without fouling or changes in material properties.

 
Prior to SSI's developments related to thin film fluoroelastomers, Silicone and Polyurethane were two candidate materials for plants which had potential problems with membrane failure such as fouling or chemical oxidation of rubber due to solvent exposure. SSI does produce silicone discs and tubes, as well as polyurethane tubes, however we much prefer the characteristics of the fluoroelastomer layered membranes, since both silicone and polyurethane have a tendency over time to suffer from tearing due to flexure failure, which is something that does not significantly afflict EPDM membranes. Neither polyurethane nor silicone is suited to cyclical operation, and neither offers a cost benefit over fluoroelastomer layered EPDM membranes.