AFD350-P Replacement PTFE membrane for 12” disc diffuser. PTFE Developed in 2004 and patented under US Patent Numbers 7396499 and 7674514, the PTFE-coated EPDM membrane is now proven technology. The PTFE surface layer protects the EPDM substrate from chemical attack, while at the same time significantly reducing surface fouling on the membrane. In time, we expect to learn that PTFE-coated EPDM membranes outlast standard EPDM, thereby reducing the life cycle costs even further. Industrially, this product is a “must have,” and has become the industry standard in pulp and paper, dairy, refinery, carbonated beverage and landfill leachate applications. Municipally, it is used by major cities worldwide due to the anticipated life cycle cost benefits and reduced maintenance. Per independent testing by Akron Rubber Development Labs, both PTFE and EPDM offer significant improvements over untreated EPDM in terms of having less plasticizer loss and less creep.