PEEK Material Temperature Range

PEEK (Polyether Ether Ketone) is one of the few engineering plastics that performs reliably across extreme temperatures. Its unique semi-crystalline structure allows it to maintain strength, dimensional stability, and chemical resistance whether exposed to high heat or deep cold. Understanding the PEEK temperature range is essential for selecting the right grade for demanding environments.

1. Key Temperature Values of PEEK

Glass Transition Temperature (Tg)

• ≈ 143°C (standard grades)

• Some modified grades reach up to 170°C

Below Tg, PEEK is rigid and strong. Above Tg, it softens but continues to carry load due to high crystallinity.

Melting Temperature (Tm)

• ≈ 341–343°C

This high melting point enables PEEK to maintain integrity far beyond the limits of most polymers.

Continuous Service Temperature

• 250–260°C

This is the true long-term working range for PEEK parts operating under steady thermal conditions.

Short-Term Heat Resistance

• Up to ~300°C

PEEK can withstand brief high-temperature spikes without losing structural stability.

Low Temperature Performance

• Functional range typically down to −40°C to −50°C

At lower temperatures, stiffness increases while impact strength decreases. For cryogenic applications, unfilled grades are preferred.

2. PEEK at High Temperatures

PEEK's strength retention at elevated temperatures is one of its biggest advantages.

• Maintains mechanical properties well above 150°C

• Resists thermal creep better than most plastics

• Filled grades (GF30, CF30) retain stiffness even closer to 200–250°C

This makes PEEK ideal for components near engines, heaters, compressors, or semiconductor tools.

3. PEEK at Low Temperatures

While famous for heat resistance, PEEK also performs reliably in cold environments.

• Maintains dimensional stability in freezing conditions

• Electrical and chemical performance remains consistent

• Brittle behavior increases below −40°C, so impact-loaded parts require validation

Applications include aerospace hardware, deep-sea connectors, and cold-environment sensors.

4. Processing Temperature Window

PEEK also requires high processing temperatures:

• Melt processing: 360–400°C

• Mold temperature: 160–200°C

• Drying at 150°C to prevent moisture defects

This high processing range corresponds directly to its exceptional material temperature range.

5. Summary: The PEEK Temperature Range

In short, PEEK offers one of the broadest usable temperature windows of any polymer - from extreme cold to near-metal high temperatures - making it a top choice for high-performance and safety-critical applications.