PEEK is the high-performance resin for parts that need strength, wear resistance and chemical resistance at around 250°C continuous. It costs far more than the other resins on these pages, so it goes where nothing cheaper survives: aerospace, oil and gas, semiconductor and medical parts.
Typical PEEK properties
| Property | Typical value | US units | Test method |
|---|---|---|---|
| Density | 1.30–1.32 g/cm³ | 0.047–0.048 lb/in³ | ASTM D792 / ISO 1183 |
| Tensile strength | 95–100 MPa | 13,800–14,500 psi | ASTM D638 / ISO 527 |
| Flexural modulus | 3.7–4.1 GPa | 537,000–595,000 psi | ASTM D790 / ISO 178 |
| Notched Izod impact | 80–95 J/m | 1.5–1.8 ft·lb/in | ASTM D256 |
| Heat deflection, 1.8 MPa (264 psi) | 150–160°C | 302–320°F | ASTM D648 / ISO 75 |
| Water absorption, 24 h | ~0.10% | ASTM D570 / ISO 62 | |
| Mold shrinkage | 0.9–1.5% | 0.009–0.015 in/in | ASTM D955 / ISO 294-4 |
Typical ranges for standard grades, dry as molded, from published data sheets. Your grade’s own data sheet and the lot COA are what count. Notched Izod uses 3.2 mm (1/8 in) bars.
Processing and drying
| Processing | Typical |
|---|---|
| Melt temperature | 670–752°F / 354–400°C |
| Mold temperature | 338–392°F / 170–200°C / 170°C is a hard minimum |
| Drying | 302–320°F / 150–160°C, 2–4 h |
| Target moisture | <0.02% |
| Max barrel residence | Stoppages: up to ~1 h with barrel at 680°F / 360°C (half that for glass-filled); longer, drop to 644°F / 340°C or purge |
| General | Typical |
|---|---|
| Clarity | Opaque |
| Chemical resistance | Excellent |
Starting points only. See the full processing temperature chart and drying guide for every resin.
What changes these numbers
- Why heat deflection looks low. Unfilled PEEK softens above its glass transition at about 143°C, so it deflects at 150–160°C under load. Glass- and carbon-filled grades deflect above 300°C.
- Hot mold. PEEK needs a mold at 170–200°C to crystallize. 170°C is a hard minimum.
- Do not average suppliers. PEEK has the widest supplier-to-supplier spread of any resin here, especially on shrinkage.
- Dry it even though it barely absorbs water. About 150–160°C for 2–4 hours, to below 0.02%.
Common PEEK grades
- Unfilled
- 30% glass-filled
- 30% carbon-filled
- Bearing grades with carbon, PTFE and graphite
- Medical and implant grades
Common questions
What is the melting point of PEEK?
About 343°C (649°F). It is molded at about 354–400°C (670–752°F).
Why is PEEK so expensive?
The monomers and polymerization are costly and few plants make it. It is priced as a specialty material, many times the cost of nylon or PBT.
What can replace PEEK?
Depending on the part: PPS, PEI, PPA or high-heat nylon. See PEEK alternatives.
Need PEEK, or something close?
A polymer chemist reviews every request, then matches your grade or finds a qualified equivalent and prices it.
What to send for an accurate quote
- The grade name, from any supplier, or a data sheet
- Color (natural, black or a custom match)
- Fill type and percentage, if any
- Melt flow, if you know it
- Quantity for this order and what you use in a year
- Ship-to city and state or province