Overview of Fluoropolymers

The chemical structure of fluoropolymers (also called fluoroplastics) primarily consists of carbon and fluorine. The particular combination of these two chemical elements arranged along the molecular chain imparts a unique set of properties to these types of carbon-fluorine based polymers.

View an in-depth table of fluoropolymer properties

Commercially available fluoropolymers include:

PTFE (Poly tetra-fluoro ethylene) – A fully fluorinated polymer available in various unmodified and modified grades

FEP (Fluorinated ethylene propylene) – A fully fluorinated copolymer

PFA, MFA (Perfluoroalkoxy) – A fully fluorinated copolymers

ETFE (Ethylene tetra-fluoro ethylene) – A partially fluorinated polymer containing hydrogen

ECTFE (Ethylene chloro tri-fluoro ethylene) – A copolymer of ethylene and chlorotrifluoroethylene

PCTFE (Poly chloro tri-fluoro ethylene) – A copolymer containing chlorine

PVDF (Poly vinyledene fluoride) – A partially fluorinated polymer containing carbon-to-carbon double bond

These materials are also known by their trade names:
PTFE, FEP, PFA – Teflon®, Neoflon®, Hyflon®
MFA – Hyflon®
ETFE – Tefzel®, Neoflon®
ECTFE – Halar®
PCTFE (or CTFE) – Neoflon® (originally Kel-F®)
PVDF – Solef®, Hylar®, Kynar®

Teflon®, Tefzel® are the trademarks of E.I. DuPont de Nemours Company
Neoflon®, Polyfon® are the trademarks of Daikin America Inc.
Hyflon®, Halar®, Hylar® are the trademarks of Solvay Solexis, Inc.
Kynar® is the trademark of Elf Atochem North America, Inc.
Kel-F® was the trademark of 3M Company ( this trade name is now discontinued)

Comparison of Material Properties

In general, the chemical resistance of fluoropolymers is superior to most other families of plastics.

One of the most unique features is their chemical inertness, which varies between the different fluoropolymers. The fully fluorinated resins such as PTFE, FEP, PFA and MFA exhibit chemical inertness to a wider range of chemicals than do the partially fluorinated polymers (CTFE, ECTFE).

Usually, however, a better property in one or two areas is accompanied by a diminished property in others. For example, PTFE is better than PVDF in chemical resistance but it has lower mechanical properties at normal ambient temperatures.

On the other hand, the flex modulus of PVDF is considerably higher than PTFE, FEP, PFA or MFA. This makes tubing of PVDF considerably more rigid than the other materials; however it has higher tensile strength at ambient temperatures.

Fully fluorinated polymers (Perfluoropolymers) such as PTFE, FEP and PFA offer better thermal (higher use temperature) and chemical resistance properties than their partially fluorinated counterparts like ECTFE or PCTFE, but trade off mechanical properties (toughness, abrasion, cut through resistance) that ECTFE and PVTFE possess.

All of these fluoropolymers are generally acceptable for a wide variety of industrial and commercial applications.

Effects of Fabrication Upon Properties

In general, it is safer to assume that fabrication procedures affect some properties of PTFE, FEP and PFA products. Certain physical properties such as tensile strength, permeability and dielectric strength vary with fabrication conditions. Examples of causes of these may be macroscopic flaws, microporosity (for PTFE) and crystallinity. The extent of the variation depends upon the specific conditions of fabrication.

Properties of PTFE, FEP and PFA that remain relatively unaffected are as follows:

  1. Chemical resistance
  2. Long-term weathering
  3. Non-stick
  4. Non-flammability
  5. Low dielectric constant and low dissipation factor
  6. High arc resistance, surface and volume resistivities
  7. Flexibility at low temperatures
  8. Thermal stability at high temperatures
  9. Low coefficient of friction