Perfluoroalkoxy PFA

The general properties of PFA are typical of other semi-crystalline high performance thermoplastics:

• excellent clarity and flexibility
   
• high continuous operating temperature
  at a maximum service temperature of 260°C, PFA can handle temperatures quite well
   
• combines the best attributes of PTFE and FEP
   
• inert
  PFA is inert aswell as chemically resistant to all common solvents
   
• maintains mechanical strength at high temperatures
   
• available in high purity grades
   
• low gas permeability
   
• smooth surface texture
   
• ultra-low levels of ionic extractables
   
• Gamma, EtO, e-beam and autoclave sterilizable
   
• inherently flame retardant
  flame resistance rating of UL 94 V-0

The physical and mechanical properties of PFA are generally similar to those of PTFE although in some cases they exceed it (i.e. tensile strength at yield and flexural modulus). The surface finish of PFA is smoother than that of either PTFE or FEP and the flex life is also generally better. However, the abrasion resistance of PFA is generally less than that of PTFE. Typical mechanical and thermal properties (at 23°C) are given in the table below.

PFA is also one of the few plastics that is both suitable for high and low temperature applications and can be used over the range of temperatures -268°C to 260°C. This is very similar to the working temperature range of PTFE but PFA has the advantage of being melt-processable.
 

The fire behavior of PFA is also excellent and PFA has no difficulty in achieving UL 94 V-0 for flame resistance. The Limiting Oxygen Index (LOI) for PFA is greater than 95, which means that there must be over 95% oxygen present to support free combustion (air only contains approximately 21% oxygen and therefore a material with an LOI of greater than 21 will probably not support burning in an open air situation).
 

Even when PFA does burn, the heat of combustion is extremely low, the amount of smoke released is minimal, and the decomposition gases have very low corrosiveness, therefore minimizing the major factors in the damage caused by real fires with cable and building related products.

PFA has excellent dielectric properties such as high volume and surface resistivity. These properties are relatively constant with changes in temperature, but are somewhat less than those of PTFE and FEP. These dielectric properties make PFA suitable for applications such as the insulation of communications cables or components for electronic devices where low dissipations are needed at high frequencies.

PFA is not fully fluorinated, and as a result, the chemical resistance of PFA is slightly less than that of the fully fluorinated polymers PTFE and FEP. Despite this, the chemical resistance of PFA is still excellent and the material has few known solvents. As a general rule PFA is preferred to FEP when extended service is required in hostile environments, and this is particularly true in conditions that might induce stress cracking.
 

PFA is suitable for food contact and is FDA compliant (FDA 21CFR.177.1550), and is also used extensively in the pharmaceutical industry.
 

PFA is also appropriate for medical applications. It is biocompatible to USP Class VI (non-toxic, non-hemolytic and non-pyrogenic) and PFA products can be sterilized by gamma, EtO, e-beam, or autoclaving.
 

PFA has good weathering resistance to sunlight, ozone and general weathering, and tests in Florida show no measurable property changes after 20 years.

PFA has a high transparency and low haze with good transmittance in both the UV and visible wavelengths. PFA also has one of the lowest refractive indexes of all polymers (1.34) and products are extremely clear and transparent. PFA can be colored almost any color but only inorganic pigments can be used due to the high processing temperatures required.