Fluorinated ethylene propylene

Fluorinated ethylene propylene (FEP) is a fluoropolymer belonging to the family of polymers known as polytetrafluoroethylene (PTFE). FEP is similar to PTFE in its properties but differs in its processing behavior and melt viscosity. It was invented by DuPont and is known for its excellent chemical resistance, high temperature resistance, and electrical insulation properties.

Properties

FEP is a copolymer of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP), which gives it a melt-processable property, unlike PTFE which cannot be melt-processed due to its high molecular weight. FEP maintains its mechanical properties in a wide temperature range from -200°C to +200°C. It is highly resistant to chemicals, UV light, and ozone, making it suitable for various industrial applications. FEP's dielectric strength and electrical properties are similar to those of PTFE, making it an excellent material for insulation in electrical and electronic applications.

Applications

FEP is widely used in the following applications:

• Wire insulation and cable insulation, especially in environments requiring chemical resistance and high temperature operation.
• Tubing for handling aggressive chemicals, due to its chemical inertness.
• Linings for chemical processing equipment, where its resistance to corrosion and high temperatures is beneficial.
• Manufacturing of semiconductor components, where purity and resistance to corrosion are required.
• Cookware and bakeware as a non-stick coating, similar to PTFE.

Processing

FEP can be processed by conventional thermoplastic processing techniques such as extrusion, injection molding, and blow molding. Its processing temperature is lower than that of PTFE, making it easier to shape and mold. However, due to its high melt viscosity, careful control of processing conditions is necessary to produce high-quality products.

Environmental and Health Aspects

FEP is considered to be a stable and inert material. It does not release harmful gases under normal processing and usage conditions. However, like all fluoropolymers, during combustion, it can release hydrofluoric acid (HF) and other toxic gases. Therefore, appropriate safety measures should be taken when handling and disposing of FEP materials.

Comparison with PTFE

While FEP and PTFE share many properties, including chemical resistance and high-temperature stability, FEP is more easily processed due to its lower melting point and can be extruded into thin films. However, PTFE has a higher maximum operating temperature and is generally considered to have better non-stick properties.

See Also

• Polymer science
• Material science
• Chemical engineering