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Perfluoroalkoxy (PFA) is thought of by many people as a “Teflon”; however, Teflon fluoropolymers are manufactured exclusively by The Chemours Company FC, LLC and the Teflon trademark may be used only under a license agreement from Chemours. The Teflon trademark is associated with a range of Chemour fluorocarbon polymers including fluorinated ethylene propylene (FEP), perfluoroalkoxy (PFA), and other materials.
Other manufacturers make similar fluorocarbon polymers, but they can’t call them “Teflon” polymers. It would be like calling all facial tissues “Kleenex.” While the Teflon trademark is licensed for use in connection with certain Nalgene labware products containing authentic Teflon brand FEP and PFA polymers, we generally refer to these fluoropolymer materials by their generic material terms on the thermofisher.com website and in literature to ensure trademark compliance.
Like all fluorocarbons, PFA is one of the superheroes of the plastics world, exhibiting remarkable chemical resistance and performing over an impressive temperature range.
PFA is translucent, flexible and feels heavy because of its high density. PFA is inert and low binding with very low extractables and trace metals content. It has the widest temperature range of the fluoropolymers from –270C to +260C with superior chemical resistance across the entire range. PFA also has a low coefficient of friction, outstanding anti-stick properties, and is flame-resistant. PFA, like many superheroes, does have a weakness—the material breaks down when exposed to sterilization-level doses of gamma irradiation.
Along with PFA’s superior chemical and physical properties comes the high cost to manufacture and subsequent high price tag for PFA products. Cost contributors include the PFA resins themselves, high processing temperatures required for molding, high product scrap rate compared with other products, and the corrosive nature of PFA at molding temperatures which shortens the life of molding equipment and requires molds and other equipment to be made from high-cost special metals.
PFA is most frequently used to make products used in critical applications where their inert properties and low extractables are valued, such as leak-proof Nalgene bottles, beakers, and graduated cylinders. PFA is also used where plastic is preferred over glass for its shatterproof properties, where the labware will be exposed to aggressive chemicals or extreme temperatures.
Temperature | Physics | Permeability | Sterilization[4] | Regulatory |
HDT[1]: 73℃ Max Use[2]: 260℃ Brittleness[12]: –270℃ | UV light: fair resistance Excellent flexibility Translucent Microwave[13]: yes Specific gravity: 2.17 | cc.-mil/ 100in2-24hr.-atm cc.-mm/ m2-24 hr.-Bar | Autoclave: yes EtO: yes Dry heat: yes Radiation: no Disinfectants: yes | Non-Cytotoxic[6]: yes Suitable for food & bev use[7]: no
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The following table contains general use exposure ratings at 20°C. The ability of plastic materials to resist chemical attack and damage is dependent also on temperature, length of exposure to the chemical, and added stresses such as centrifugation. For more detailed chemical resistance ratings for Nalgene products and materials, please consult the resources referenced at the bottom of this page.
Class | General rating |
Acids, dilute or weak | E |
Acids*, strong and concentrated | E |
Alcohols, aliphatic | E |
Aldehydes | E |
Bases/alkali | E |
Esters | E |
Hydrocarbons, aliphatic | E |
Hydrocarbons, aromatic | E |
Hydrocarbons, halogenated | E |
Ketones, aromatic | E |
Oxidizing agents, strong | E |
*Except for oxidizing acids; for oxidizing acids, see "Oxidizing agents, strong."
E | 30 days of constant exposure causes no damage. Plastic may even tolerate for years. |
G | Little or no damage after 30 days of constant exposure to the reagent. |
F | Some effect after 7 days of constant exposure to the reagent. Depending on the plastic, the effect may be crazing, cracking, loss of strength, or discoloration. |
N | Not recommended for continuous use. Immediate damage may occur including severe crazing, cracking, loss of strength, discoloration, deformation, dissolution, or permeation loss. |
One of the nice things about using PFA labware is that chemical compatibility is of virtually no concern. You can enjoy the safety aspect of using shatter-proof labware without thinking much about what’s going in it. There are a few things to consider, though, to get the most out of your PFA labware purchase.
Plastic material identification
Be sure the labware you think is PFA really is a fluoropolymer. Nalgene PFA bottles will have “PFA” molded into the bottom. Other clues are the heavy feel of the labware piece for its size, translucency that’s just a bit milky-white or hazy in appearance, and lubricious (slippery) surface.
Use, care, and cleaning
Never use PFA labware over an open flame or directly on a hot plate. Hot plates can have hot spots that can damage PFA. Additionally, PFA is a poor heat conductor and will not allow the contents of the PFA vessel to heat efficiently.
PFA labware will scratch if exposed to abrasive materials. Use only soft sponge-type cleaning utensils rather than brushes. And if you put your PFA labware in the dish washer, cover any hard metallic spindles with a piece of flexible tubing to prevent them from scratching your labware.
Autoclaving
PFA labware and bottles are autoclavable. The recommended autoclave cycle for empty containers is 121°C at 15 psi for 20 minutes. Care must be taken to allow free air circulation into and out of vessels during the autoclave cycle, especially during the venting and cooling stages. If the container is not properly vented, collapse or implosion (sometimes confused with melting) can occur.
When autoclaving bottles, the cap threads must be completely disengaged from the container; the cap can be set loosely over the mouth opening at a rogue angle to ensure the threads don’t inadvertently engage. Once the container is completely cooled, the cap can be aseptically tipped into place and tightened down.
Footnotes:
[1]. Heat Deflection Temperature is the temperature at which an injection molded bar deflects 0.1” when placed under 66 psig (ASTM D648) of pressure. Materials may be used above Heat Deflection Temperatures in non-stress applications; see Max. Use Temp.
[2]. Max. Use Temp. °C: this is related to the maximum continuous use temperature, ductile/brittle temperature and glass transition temperature, and represents the highest temperature at which the polymer can be exposed for the matter of minutes to 2 hours where there is little or no loss of strength.
[4]. STERILIZATION: Autoclaving (121°C, 15 psig for 20 minutes)—Clean and rinse items with distilled water before autoclaving. (Always completely disengage thread before autoclaving.) Certain chemicals which have no appreciable effect on resins at room temperature may cause deterioration at autoclaving temperatures unless removed with distilled water beforehand.
EtO Gas—Ethylene Oxide: 100% EtO, EtO:Nitrogen mixture, EtO:HCFC mixture
Dry Heat—exposure to 160°C for 120 minutes without stress/load on the polymer parts
Disinfectants—Benzalkonium chloride, formalin/formaldehyde, hydrogen peroxide, ethanol, etc.
Radiation—gamma or beta irradiation at 25 kGy (2.5 MRad) with unstabilized plastic
[6]. “Yes” indicates the resin has been determined to be non-cytotoxic, based on USP and ASTM biocompatibility testing standards utilizing an MEM elution technique with WI38 human diploid lung cell line.
[7]. Resins meet requirements of CFR21 section of Food Additives Amendment of the Federal Food and Drug Act. End users are responsible for validation of compliance for specific containers used in conjunction with their particular applications.
[12]. The brittleness temperature is the temperature at which an item made from the resin may break or cracked if dropped. This is not the lowest use temperature if care is exercised in use and handling.
[13]. Ratings based on 5-minute tests using 600 watts of power on exposed, empty labware. CAUTION: Do not exceed Max. Use Temp., or expose labware to chemicals which heating will cause to attack the plastic or be rapidly absorbed.
Contact the support representative team by phone at +1-585-586-8800 or (1-800-625-4327 US toll free), or email your request to technicalsupport@thermofisher.com.
In Austria, France, Germany, Ireland, Switzerland, and the United Kingdom please contact technical support by phone at +800-1234-9696 (toll free) or +49-6184-90-6321, or email your request to techsupport.labproducts.eu@thermofisher.com.
Regulatory support: for regulatory documentation of product or material claims, please contact Nalgene regulatory support at RocRegSupport@thermofisher.com.
For chemical compatibility ratings by chemical, temperature, and length of exposure, use the Nalgene General Labware Chemical Compatibility Guide
For centrifugeware chemical compatibility ratings, please use ONLY the Centrifuge Ware Chemical Resistance
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