PTFE vs PEEK

Published on November 6 2020

Updated 12/02/2026

High-performance polymers are defined not just by their temperature capability, but also by how well they maintain mechanical, chemical, and dimensional stability in extreme operating environments.

For engineers working in Oil & Gas, Aerospace, Hydrogen & Renewables, Semiconductor and demanding industrial systems, material selection directly impacts:

• Safety

• Reliability

• Compliance

• Maintenance cycles

• Total lifecycle cost

Two of the most frequently specified materials are PTFE (Polytetrafluoroethylene) and PEEK (Polyether Ether Ketone).

Both operate at similar maximum temperatures. However, their behaviour under load, in aggressive media, and in precision applications differs significantly.

Understanding those differences is critical when specifying components such as seals, valve seats, bearings, insulators or structural parts.

Table of Contents

PTFE: Properties, Advantages & Considerations

PEEK: Properties, Advantages & Considerations

Industry Application Considerations

PTFE vs PEEK: Property Comparison

The Critical Difference

Frequently Asked Questions (FAQs)

 

PTFE (Polytetrafluoroethylene)

PTFE is one of the most chemically resistant engineering materials available and remains a cornerstone polymer across multiple high-risk industries.

Key Properties

• Continuous service temperature: up to ~260°C

• Virtually chemically inert

• Extremely low coefficient of friction (among the lowest of any solid)

• Excellent dielectric strength

• High elongation and flexibility

• Moderate mechanical strength

Where PTFE Excels

PTFE performs exceptionally well in environments involving:

• Strong acids and aggressive chemicals

• Cryogenic conditions (including LNG systems)

• High-purity semiconductor processes

• Low-friction dynamic sealing applications

• Electrical insulation across wide temperature ranges

Processing Considerations

Although PTFE is technically a thermoplastic, its extremely high melt viscosity prevents conventional injection moulding.

Instead, it is:

1. Cold-formed (ram extrusion or compression moulded)

2. Sintered to fuse polymer particles

This influences:

• Tolerance capability

• Component geometry

• Production lead times

For precision components, machining expertise is critical.

PEEK (Polyether Ether Ketone)

PEEK is a high-strength semi-crystalline thermoplastic known for its structural performance in demanding mechanical environments.

Key Properties

• Continuous service temperature: up to ~250–260°C

• High tensile and flexural strength

• Excellent creep resistance

• Low thermal expansion

• High stiffness

• Good chemical resistance (not universal)

Where PEEK Excels

PEEK is particularly suited to:

• High-pressure Oil & Gas components

• Aerospace structural parts

• Hydrogen compression systems

• Semiconductor wafer handling

• Industrial pump and compressor components

PEEK retains mechanical integrity under sustained load and elevated temperatures, a key differentiator from PTFE.

Chemical Limitations

PEEK is resistant to most organic and aqueous media, but it can be attacked by:

• Concentrated sulphuric acid

• Certain halogens

• Some halogenated compounds at elevated temperatures

Material compatibility must always be verified in aggressive chemical service.

Processing Advantages

Unlike PTFE, PEEK can be:

• Injection moulded

• Extruded

• Hot compression moulded

This allows:

• Tighter tolerances

• Complex geometries

• Improved repeatability

Although PEEK carries a significantly higher material cost, it often reduces lifecycle cost in high-load or safety-critical applications.

Industry Application Considerations

Oil & Gas

• PTFE: Ideal for chemically aggressive valve seats, seals and gaskets.

• PEEK: Preferred for anti-extrusion rings, backup rings and high-pressure structural components.

Aerospace

• PTFE: Used in low-friction bearings and insulation systems.

• PEEK: Used in lightweight structural brackets, compressor components and load-bearing parts where metal replacement is required.

Hydrogen & Renewables

Hydrogen systems demand materials resistant to permeation, pressure cycling and temperature fluctuation.

• PTFE: Suitable for sealing in chemically aggressive renewable processing systems.

• PEEK: Often preferred in hydrogen compression, high-pressure valve components and structural applications due to strength and dimensional stability.

Semiconductor

• PTFE: Ideal for high-purity chemical handling and ultra-low contamination environments.

• PEEK: Used for high-strength, dimensionally stable wafer handling and tooling components.

Industrial Applications

• PTFE: Sliding bearings, skidways, low-friction liners.

• PEEK: Pump components, wear rings and load-bearing assemblies.

PTFE vs PEEK: Property Comparison

^{Values are typical reference figures only and should not be used for final design without verification.}

The Critical Difference: Strength vs Chemical Inertness

If your application prioritises:

• Chemical resistance

• Electrical insulation

• Extremely low friction

• Flexibility

→ PTFE is often the better solution.

If your application requires:

• Structural integrity under load

• Dimensional stability

• Tight tolerances

• Long-term creep resistance

→ PEEK is frequently more appropriate.

In many engineered systems, material selection may also involve filled grades or compound modifications to optimise performance.

Frequently Asked Questions (FAQs)

Is PEEK stronger than PTFE?

Yes. PEEK has significantly higher tensile strength, stiffness and creep resistance than PTFE. It is better suited to load-bearing and structural applications.

Is PTFE more chemically resistant than PEEK?

Generally, yes. PTFE is considered virtually inert and offers superior resistance to strong acids and aggressive chemicals. PEEK can be attacked by concentrated sulphuric acid and certain halogens.

Can PTFE and PEEK both operate at 250°C?

Yes. Both materials can operate continuously at approximately 250–260°C. However, their mechanical performance at that temperature differs significantly.

Which material is better for hydrogen applications?

It depends on the application.
PEEK is often preferred in high-pressure hydrogen compression systems due to its strength and dimensional stability. PTFE is commonly used for sealing where chemical resistance is critical.

Material compatibility testing is recommended in hydrogen service.

Why is PEEK more expensive than PTFE?

PEEK is a more complex, high-performance polymer with superior mechanical properties and processing versatility. While initial material cost is higher, it often reduces lifecycle cost in demanding applications.

Is PTFE suitable for high-pressure applications?

PTFE can be used in high-pressure environments, particularly in sealing. However, due to creep under load, it is often supported by backup rings or replaced with PEEK in structural high-pressure components.

How do I choose between PTFE and PEEK?

Material selection should consider:

• Temperature

• Chemical exposure

• Pressure and load

• Tolerance requirements

• Compliance standards

• Service life expectations

Engineering consultation early in the design phase reduces the risk of failure and overspecification.

To find out how we can support your projects, contact info@fluorocarbon.co.uk

---