PEEK Thermal Stability

A Comprehensive Guide

Polyether ether ketone (PEEK) is renowned for its exceptional thermal stability, making it a standout thermoplastic polymer in high-performance applications. PEEK exhibits a melting point of 343°C and a glass transition temperature of 143°C, enabling it to withstand continuous working temperatures up to 300°C. Although it performs admirably at sustained high temperatures, PEEK is susceptible to thermal degradation when exposed to temperatures between 575°C and 580°C, which leads to noticeable mass loss. Notably, the thermal decomposition onset temperature for PEEK remains consistent whether in an air environment or under an inert atmosphere, a characteristic that sets it apart from many other polymers.

The high melting point and glass transition temperature of PEEK contribute to its ability to retain mechanical properties at elevated temperatures. Additionally, PEEK demonstrates excellent dimensional stability and rigidity under heat. Its resistance to a wide range of chemicals—including acids, bases, hydrocarbons, and radiation—further enhances its suitability for use in harsh environments.

Common Questions About PEEK Thermal Stability

Is PEEK thermally stable?

Yes, PEEK exhibits superior resistance to thermal degradation, with a continuous use temperature of up to 260°C and a melting point of 343°C. Thermal degradation, marked by mass loss, begins between 575°C and 580°C.

At what temperature does PEEK degrade?

PEEK begins to degrade at approximately 450°C.

What temperature can PEEK seals withstand?

PEEK seals can withstand a glass transition temperature of around 143°C (289°F) and melt at approximately 343°C (662°F). Certain grades are operable at temperatures up to 250°C (482°F) and exhibit high resistance to thermal degradation and chemical attacks.

Can PEEK be thermoformed?

Yes, PEEK can be thermoformed at temperatures between 140°C and 160°C (284°F and 320°F) using common techniques such as vacuum forming, drape forming, air slip forming, and plug assist forming.

What is the temperature limit for PEEK material?

PEEK can be continuously used at temperatures up to 250°C (482°F) and maintains its physical properties in hot water or steam. It is a high-strength alternative to fluoropolymers in hostile environments, with a V-0 flammability rating and low smoke and toxic gas emission when exposed to flame.

Is PEEK a thermoplastic or thermoset?

PEEK is a semi-crystalline thermoplastic.

What temperature is required for PEEK enclosures?

PEEK enclosures are typically processed at temperatures between 370°F and 450°F.

What is the heat deflection temperature of PEEK?

PEEK has a heat deflection temperature exceeding 300°F, along with excellent resistance to various cleaning chemicals.

What is the annealing temperature for PEEK?

A common annealing process for PEEK involves a 2-hour exposure to 200°C (392°F), a temperature well above its Tg, to achieve optimal crystallinity.

What is the minimum service temperature range for PEEK?PEEK's service temperature extends down to at least -70°C (-94°F). At extremely low temperatures, PEEK, like most plastics, becomes more brittle.