PTFE is one of the most chemically inert compounds, however, has very little elasticity, which can reduce flow rates upto 20%. A rubber back-up diaphragm is required to provide flexibility and memory. Many other materials, usually derivates of the above, have been developed by individual pump companies for use in their own pumps. 

These PTFE protected diaphragms combine the chemical resistance associated with PTFE with the flex characteristics of an elastomer. The PTFE is chemically bound to the underlying rubber. Since it is manufactured as one piece, the risk of separation normally associated with two-piece overlaid diaphragms is eliminated, increasing time on-line. One-piece construction avoids the possibility of leakage and also prevents abrasive particulate material getting between the PTFE and rubber, which could cause damage and lead to reduced diaphragm lifetime.