Polytetrafluoroethylene (PTFE) is a tetrafluoroethylene polymer featuring a unique combination of physical-chemical features that make it different from any other plastic material. The main features of PTFE Lined Pipe are:
- extreme chemical inertness
- excellent heat resistance
- optimum dielectric properties
- not hygroscopic and maximum resistance against solvents
- optimum resistance to aging
- self-lubricating properties and minimum friction coefficient
PTFE resists nearly all chemical reactants. At high pressure and high temperature, it is attacked only by elemental alkali metals, chlorotrifluorides, and elemental fluorine. For all solvents, up to 300 degrees, C. PTFE is indifferent It can only be swelled and melt at temperatures around the crystalline melting point by some heavily fluorinated oils.
PTFE has a factor of low heat transmission, and can, therefore, be considered a Thermo insulating material. This also displays flame retardant properties and is stable for an indefinite period of time at 260 degrees C.
Within a wide range of temperatures and frequencies, PTFE has optimal dielectric properties. Since water absorption is practically non-existent, even after prolonged exposure to weather agents, these properties are preserved. The operating temperature basically doesn’t affect electrical strength. The PTFE arc resistance is considerable and the spark does not generate carbon residues but only non-conductive vapors. The other electrical properties (dielectric constant, surface resistance, volume resistance, power factor, etc.) show very interesting values.
The above properties make PTFE Lined Elbow the product of choice for challenging chemical applications. There are however different applications that demand higher performance. In this case, it employs filled PTFE grades. In this case, PTFE is filled with special powdered additives such as glass fiber, carbon graphite, molybdenum disulfide, bronze ceramic powder, and even two or more filler mixtures. Depending on the type and volume of filler it is possible to:
- increase compressive strength
- increase wear resistance
- reduce the thermal expansion coefficient
- vary volume and surface resistivity
- Increase hardness.
Perfluoroalkoxy alkanes (PFA) is a fluoropolymer. It is produced by copolymerization of tetrafluoroethylene (C2F4) and perfluoroethers (CF2F3ORf). In terms of its properties, this polymer is similar to polytetrafluoroethylene (PTFE). The major difference is that the alkoxy substituents enable the polymer to be melt-processed.
PFA is melted using conventional thermoplastic processing methods, including injection, transfer, blow and compression molding and extrusion.
It is comparatively soft thermoplastic with a low tensile strength and creep resistance than many other engineering plastics. It is chemically inert and has a low dielectric constant over a wide range of frequencies.
PFA is used when prolonged service is needed in harsh environments involving chemical, thermal and mechanical stress. PFA offers superior melt strength, high processing temperature stability, excellent crack and stress resistance, low friction coefficient.
It has a high resistance to creep and retention of properties after service at 260 degrees C (500 degrees F).
PFA has high transparency (with strong ultraviolet transmittance and visible wavelengths). It has long-term weatherability and outstanding resistance to ozone, sunshine, and climate.
Important applications include liners for pipe and chemical processing equipment, roller covers and several wire and cable applications, including aircraft wire, plenum cable, and fire alarm cable and well logging cable.