ETFE vs. PTFE: The “Big 2” Wiring Insulations

About ETFE vs. PTFE, Insulation is an essential part of every wire that carries electricity, preventing electricity flow from spreading.

Insulation for wires is often a plastic or polymer, with ETFE and PTFE some of the most prevalent.

However, much like their English acronyms, they are often mixed up.

This piece will discuss the similarity between the two kinds of wire insulation and what sets each apart.

ETFE vs. PTFE: Similarities

ETFE and PTFE share many characteristics.


It’s common knowledge that polymer materials significantly impact the built world. There are an infinite number of them, each with a unique function.

The potential of  ETFE and PTFE as outdoor materials is growing.

Most of the aeronautical wire insulation on the market is made from PTFE and ETFE polymers.

ETFE is becoming popular in construction because it can withstand normal use and is simple to manufacture.

However, PTFE is finding more and more uses in technological settings, such as cables and factories.

Its elasticity and tolerance to high temperatures open up a wide range of potential uses for the material. 


High voltage wire and cable insulated with polytetrafluoroethylene (PTFE) or ethylene tetrafluoroethylene (ETFE) provide many of the same advantages as FEP:

  • High dielectric strength
  • Good high-temperature characteristics
  • Strong resistance to chemicals
  • Prevent the absorption of moisture.
  • Non-stick properties
  • Low coefficient of friction
  • Biocompatibility
Electrical power cable

Electrical power cable

ETFE vs. PTFE: Differences

Wire insulation made from PTFE (polytetrafluoroethylene) or ETFE (ethylene tetrafluoroethylene) is popular owing to its high-performance characteristics, low dielectric constant, and great chemical resistance.

Yet, they are often confused with one another, as is their spelling. Here is a look at how they vary and how designers might put that information to use.


ETFE (DuPont trade name Tefzel®) is a carbon, fluorine, and hydrogen atom substance.

PTFE (DuPont trade name Teflon®) is a fluorocarbon composed of carbon and fluorine atoms.

These polymers are ideal for aviation and radio wire because of their great corrosion resistance, strength, and outstanding dielectric characteristics.

Physical Properties

ETFE’s tensile strength, elongation, and rip strength are all superior to PTFE’s, making it mechanically stronger.

ETFE’s tensile strength is up to 34% higher than PTFE’s. On the other hand, PTFE has substantially greater flexibility and elongation to break (66%).

ETFE’s modulus of elasticity is also lower than that of PTFE, making it a better choice for applications that require a great deal of flexibility.

PTFE’s low coefficient of friction is a major benefit.

As PTFE’s coefficient of friction is just 1/3 that of ETFE, it makes for a superior wire insulator in situations where bundles of wires could rub against one another.

It is more of a worry with PTFE insulations because of cold flow, the insulation’s migration process from a stress point.

Thermal Properties

ETFE and PTFE can resist temperatures much over their melting points without suffering ill effects.

Nonetheless, PTFE is better suited for high-temperature applications.

It has a higher melting point (327 °C) than ETFE (267 °C) and can keep its characteristics at greater temperatures.

Also, PTFE has a lower Limiting Oxygen Index, the minimal percentage concentration of oxygen at which the polymer may catch fire.

A lower limiting oxygen index gives it an advantage in environments with a greater oxygen concentration.

With a Limiting Oxygen Index of over 95%, PTFE is more suited to settings with high oxygen concentrations than ETFE, which has a lower value (about 36%).

Chemical Resistance

ETFE is more resistant to chemicals, including strong acids and alkalis, than PTFE.

On the other hand, PTFE is superior in situations where exposure to organic solvents or gases is problematic because it is more impervious to these elements.

Electrical Properties

Electrically, both ETFE and PTFE are very good insulators due to their low dielectric constants and high breakdown voltages.

However, PTFE is preferable for high-frequency applications since its dielectric constant is somewhat lower than ETFE’s.


Fluorine outgassing is a problem that persists over time with both materials.

Hydrofluoric acid, formed when fluorine atoms in these substances combine with hydrogen atoms, is dangerous in confined spaces.

The outgassing from ETFE is much less than that of PTFE. ETFE’s lower molecular weight and simpler molecular structure make it better to let trapped gases escape.

The lower melting point of ETFE compared to PTFE allows it to be treated at lower temperatures, minimizing the potential for outgassing.


ETFE is more versatile than PTFE in processing since it may be extruded, injected, and molded into almost any form.

Conversely, PTFE is more difficult to process and requires specialist equipment like paste extruders or sintering furnaces.

PTFE and ETFE wires come in many types and kinds.

  1. Crosslinked ETFE wires are lightweight and impervious to fluids, oils, and moisture. By fusing the ETFE polymers, the crosslinking process increases the material’s strength and tolerance to heat.
  2. Stand-alone ETFE wires are durable and corrosion-resistant across a broad temperature range. Not only is it resistant to chemicals and electricity, but it can also withstand high-energy radiation.
  3. Stand-alone PTFE wires have a very high melting point and are chemical resistant. It is a widely used polymer in the aviation wiring industry.
  4. PTFE wires with polyimide coating have a desirable abrasion resistance that the underlying PTFE wire lacks. Moreover, the hydrophobic coating prevents the wire from being damaged by rain and other wet conditions.
Electrical grounding cables

Electrical grounding cables

Wire Insulation Selection Guidelines

If you care about the security and dependability of your electrical infrastructure, you need to pay close attention to the insulation material you choose for your wires.

Here are things to keep in mind when picking out wire insulation.

Comparison Chart of PTFE, FEP, PFA, ETFE 

Chemical ResistanceExcellentExcellentExcellentExcellent
Temperature Resistance-200°C to 260°C-200°C to 200°C-200°C to 260°C-100°C to 150°C
Melting Point327°C260°C305°C260°C
Tensile StrengthLowLowLowHigh
Dielectric StrengthHighHighHighHigh
Coefficient of FrictionVery lowLowLowLow
Processing MethodsLimitedExtrusion, Injection MoldingExtrusion, Injection MoldingExtrusion, Injection Molding

Cons of different types of wire insulation

Insulation typesDisadvantages
FEP and PTFE(Dupont TM Teflon)Easily damaged by cold flow when strained (bent) over a small radius or laced too tightly. Degraded by sun exposure greater than 5x 105RADSFEP is easily broken and has little resistance to cutting.Most robust insulation
ETFE (Dupont TM Tefzel)In a 30% oxygen atmosphere, several types of ETFE insulation fail the flammability test. When tested for flammability in an atmosphere containing 30% oxygen, some ETFE insulation falls short. Decays in the presence of gamma radiation, over 106 RADS
Crosslinked ETFE(Dupont TM Tefzel)Certain ETFE insulations’ flammability is insufficient in a 30% oxygen atmosphere. Inflexible compared to extruded ETFETougher to work with than Teflon PTFE
Polyimide (Dupont TM Kapton)Robustness – not easily disrobed. It can take in water and hold it. Unfavorable climate resistanceExposure to abrasions and wounds increases the risk of wet-arc and dry-arc tracking. Having a harder time bending, easily damaged by sunlight
Silicon RubberEasily broken, not very robust, and easily eroded by waterOutgassing regulation requires processingFlammableNo insulating rubber-siped wires or cables.

Pros of different types of wire insulation

Insulation typesAdvantages
FEP and PTFE(Dupont TM Teflon)Excellent high-temperature properties. Use PTFE Teflon for solder applications and FEP for jacket material. Non-flammable Good outgassing characteristics most flexible of all insulationsGood weather ability resists moisture absorption and atomic oxygen erosion.
ETFE (Dupont TM Tefzel)Able to withstand rough treatment before and after installation Excellent resistance to both hot and cold temperaturesExcellent outgassing properties Long flex life typical cold flow characteristics
Crosslinked ETFE(Dupont TM Tefzel)Tougher than regular ETFEAbrasive and cold-flow resistantIncreased resistance to the effects of radiation superior to ETFE’s typical upper-temperature limit the ability to release gases effectively
Polyimide (Dupont TM Kapton)The most lightweight insulating material for wiresExcellent mechanical, thermal, and electric characteristics Superb resilience to cold flow and cuttingSuperior protection against radiation high-quality outgassing properties
Silicon RubberVery malleable, even at chilly temperaturesSuperior resistance to corona at high voltage high level of radiation resistance High resistance to the movement of cold
Electric cable

Electric cable

Wrapping Up

When it comes to wire insulation, both ETFE and PTFE are good options.

They’re both non-stick, resistant to high heat, and have low friction coefficients. They are also electrically insulating and biocompatible.

Yet, ETFE and PTFE have enough distinctions that one may be preferable. The choice depends on the task at hand.

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