What is Polytetrafluoroethylene? (PTFE)

Updated 10/02/2026

PTFE/Teflon: Properties, Structure, and Performance Explained

Polytetrafluoroethylene (PTFE) is a tough, flexible, non-resilient thermoplastic best known for its exceptional chemical resistance, outstanding thermal stability, and extremely low coefficient of friction. While PTFE has only moderate tensile strength compared to other engineering polymers, its unique combination of properties makes it indispensable in some of the most demanding industrial environments.

Table of Contents

Key Material Properties of PTFE

Typical Applications of PTFE

Processing and Manufacturing of PTFE

Why PTFE Has Such Unique Properties: A Molecular Explanation

Low Friction and Electrical Performance Explained

PTFE at the Molecular Level

Summary

Key Material Properties of PTFE

PTFE exhibits a distinctive balance of physical, thermal, electrical, and chemical characteristics:

• Extremely low coefficient of friction, among the lowest of any solid material

• Excellent thermal stability, with a melting point of approximately 327 °C

• Outstanding chemical resistance, unaffected by almost all chemicals at room temperature

• Exceptional electrical insulation, stable across a wide temperature and frequency range

• High volume resistivity, typically exceeding 10¹⁸ Ω·m, with negligible power factor

• Excellent weathering and UV resistance

• Non-stick surface with very low surface energy

At ambient temperatures, PTFE is chemically inert to virtually all solvents and reagents. Only molten alkali metals and elemental fluorine under extreme conditions are known to attack PTFE.

Typical Applications of PTFE

The combination of chemical inertness, thermal resistance, electrical insulation, and low friction allows PTFE to be used across a wide range of industries and applications, including:

• Seals and gaskets

• Valve components and pump parts

• Bearings and slide elements

• Wire and cable insulation

• Transformer insulation

• Printed circuit boards (PCBs)

• Anti-stick and protective surface coatings

PTFE is also widely used in aerospace and defence applications, including aircraft and missile systems, where resistance to high temperatures and aggressive environments is essential.

Processing and Manufacturing of PTFE

Although PTFE is classified as a thermoplastic, it cannot be processed using conventional melt-processing techniques such as injection moulding or extrusion. This is due to its extremely high melt viscosity, which prevents it from flowing when heated.

Instead, PTFE is processed using:

1. Cold forming (compression moulding or ram extrusion)

2. Sintering, a controlled heat treatment process in which PTFE particles fuse together to form a solid, coherent moulding

This unique processing route contributes to PTFE’s high crystallinity and distinctive mechanical behaviour.

Why PTFE Has Such Unique Properties: A Molecular Explanation

The exceptional performance of PTFE originates from its molecular structure.

Fluorine is the most electronegative element in the periodic table, significantly more so than carbon. In the PTFE molecule, fluorine atoms strongly attract shared electrons from the carbon backbone, creating highly stable carbon–fluorine (C–F) bonds.

Because fluorine atoms are relatively large, they prevent the polymer chains from packing into a simple planar structure during crystallisation. Instead, PTFE forms a twisted helical (zigzag) molecular configuration, with fluorine atoms tightly packed around a spiral carbon–carbon backbone.

This dense fluorine shielding and the strength of the C–F bond are the primary reasons for:

• PTFE’s high melting point (327 °C)

• Exceptional thermal and chemical stability

Low Friction and Electrical Performance Explained

Although fluorine atoms are highly electronegative and carry partial negative charges, the symmetrical arrangement of PTFE chains causes individual dipole moments to cancel out. As a result, PTFE remains electrically neutral overall.

This molecular neutrality leads to:

• Very low surface energy, resulting in a low coefficient of friction

• Low dielectric constant

• Extremely high volume and surface resistivity

• High elongation, but relatively low tensile strength and abrasion resistance

These characteristics explain why PTFE performs exceptionally well as a sealing and insulating material, but is often modified or filled when higher wear resistance or mechanical strength is required.

PTFE at the Molecular Level

On a molecular scale, PTFE is a linear polymer with:

• Very high molecular weight (long polymer chains)

• Crystallinity is typically in the range of 50–70%, depending on processing conditions

The balance between crystalline and amorphous regions strongly influences PTFE’s mechanical behaviour, wear performance, and dimensional stability.

Summary

PTFE is a unique engineering polymer whose performance is driven by its molecular structure rather than high mechanical strength. Its unmatched chemical resistance, thermal stability, electrical insulation, and low friction make it an essential material for sealing, electrical, chemical processing, and aerospace applications where reliability is critical.

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