Teflon and other Fluorinated Ethylene Propylene (FEP) Labware

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Like all fluorocarbons, FEP is one of the superheroes of the plastics world, exhibiting remarkable chemical resistance and performing over an impressive temperature range. 

FEP is translucent, flexible, and feels heavy because of its high density. It is lubricious to the touch due to its very low coefficient of friction. FEP is inert and low binding with very low extractables and trace metals content. FEP resists all known chemicals except molten alkali metals, elemental fluorine, and fluorine precursors at elevated temperatures. It should not be used with concentrated perchloric acid. FEP can be used at temperatures as high as +190°C, and maintains is protective elastic properties down to –270°C.  

FEP may be sterilized repeatedly by all known chemical and thermal methods. It can even be boiled in nitric acid. FEP, like many superheroes, does have a weakness—the material breaks down when exposed to sterilization-level doses of gamma irradiation.

Along with FEP’s superior chemical and physical properties comes the high cost to manufacture and subsequent high price tag for FEP products. Cost contributors include the FEP resins themselves, high processing temperatures required for molding, high product scrap rate compared with other products, and the corrosive nature of FEP at molding temperatures which shortens the life of molding equipment and requires molds and other equipment to be made from high-cost special metals.

FEP 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 and centrifuge tubes. FEP 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.  

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.

*Except for oxidizing acids; for oxidizing acids, see "Oxidizing agents, strong."

One of the nice things about using FEP 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 FEP labware purchase.

Plastic material identification
Be sure the labware you think is FEP really is a fluoropolymer. Nalgene FEP bottles will have “FEP” 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 FEP labware over an open flame or directly on a hot plate. Hot plates can have hot spots that can damage FEP. Additionally, FEP is a poor heat conductor and will not allow the contents of the FEP vessel to heat efficiently.

FEP labware will scratch if exposed to abrasive materials. Use only soft sponge-type cleaning utensils rather than brushes. And if you put your FEP labware in the dish washer, cover any hard metallic spindles with a piece of flexible tubing to prevent them from scratching your labware.

Centrifugation
Because FEP is a very flexible material Nalgene FEP centrifuge tubes and bottles must be filled to 100% capacity before spinning. This prevents the shoulder of the tube or bottle from collapsing under the centrifugal force of the spin. Additionally, FEP centrifuge tubes should be used only in refrigerated centrifuges for high-speed centrifugation. Centrifuge bottles are recommended only for low speed centrifugation and are rated for temperatures from –100°C to +150°C. Refer to specific product instructions for maximum speed ratings and use of sealing caps to maintain leakproof performance at higher speeds.    

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.
[3]. The plastic will absorb and retain significant amounts of heat resulting in an unexpectedly hot surface.
[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.