Perfluoroalkoxy alkane

PFA
Density[1]	2150 kg/m3
Flexural modulus(E)	586 MPa
Tensile strength(t)	24 MPa
Elongation @ break	300%
Folding endurance	No break
Notch test
Melting point	315 °C
Maximum operating
temperature	260 °C
Water absorption (ASTM)	<0.03 % after 24 hours
Dielectric constant (Dk)
at 1MHz	2.1
Dissipation factor
at 1MHz	0.0001
Arc resistance	< 180 seconds
Resistivity at 50% R.H.	> 1016 Ω m

Perfluoroalkoxy alkane polymers are used to fabricate tube to handle aggressive chemicals.

Perfluoroalkoxy alkanes or PFA are fluoropolymers. They are copolymers of tetrafluoroethylene (C₂F₄) and perfluoroethers (C₂F₃OR^f, where R^f is a perfluorinated group such as trifluoromethyl (CF₃)). In terms of their properties, these polymers are similar to polytetrafluoroethylene (PTFE). The big difference is that the alkoxy substituents allow the polymer to be melt-processed. On a molecular level, PFA has a smaller chain length, and higher chain entanglement than other fluoropolymers. It also contains an oxygen atom at the branches. This results in a material that is more translucent and has improved flow, creep resistance, and thermal stability close to or exceeding PTFE.^[2] Similarly advantaged processing properties are found in fluorinated ethylene propylene (FEP), the copolymer of tetrafluoroethylene and hexafluoropropylene.^[3]

Applications

PFA is commonly used as material for piping and fittings for aggressive chemicals, as well as corrosion-resistant lining of vessels in the chemical-processing industry. Typical applications are in the construction of gas scrubbers, reactors, containment vessels, and piping.^[4] In coal-fired power plants, it is used as lining for heat exchangers. By channeling crude gas through the PFA-lined apparatus the gas stream can be cooled beyond its condensation temperature without damaging the heat exchanger. Its use contributes to increasing the efficiency of the whole plant.^[5]

References