What is PEEK?
PEEK (Polyetheretherketone) is a high-performance engineering plastic known for its ability to withstand extreme conditions—high temperatures, heavy loads, and aggressive chemicals—while maintaining dimensional stability and precision.
Whether you’re designing for aerospace, medical devices, or high-stress industrial parts, PEEK offers a rare combination of mechanical strength, thermal stability, and chemical resistance that makes it a go-to material for demanding applications.
In this guide, you’ll learn:
- What are the properties of PEEK?
- How it’s produced and processed
- Where it’s most commonly used
- What makes PEEK unique compared to other engineering plastics
- How to choose the right grade
- What future trends are shaping its development
By the end, you’ll have a clear understanding of whether PEEK fits your application—and what to consider if you’re ready to use it.
What Are the Properties of PEEK?
PEEK is a semi-crystalline thermoplastic known for outstanding performance. Its structure ensures high mechanical strength, thermal stability, and chemical resilience.
| Property | Specification / Range |
|---|---|
| Temperature Resistance | Up to 250 °C continuous operation; 300 °C short-term |
| Tensile Strength | ~ 90–100 MPa |
| Modulus of Elasticity | ~ 3.6 GPa |
| Elongation at Break | ~ 50–100 % |
| Chemical Resistance | Resistant to solvents, acids, bases |
| Wear Resistance | Excellent under sliding/friction |
| Thermal Expansion | Low; stable dimensions |
| Flame Retardancy | UL94 V-0 rating, self-extinguishing |
| Biocompatibility | ISO 10993; used in implants |
| Radiation Resistance | Suitable for sterilization cycles |
Its toughness and dimensional stability under load make it a go-to material where mid-to-high performance is required.
How Is PEEK Produced?
Producing high-performance PEEK resin requires a controlled multi-step chemical process to ensure its purity, consistency, and performance:
1. Polymerization
Industrial PEEK is synthesized via nucleophilic aromatic substitution, where:
- Hydroquinone reacts with 4,4’-difluorobenzophenone
- The reaction occurs in a high-temperature, alkaline solvent
- This forms semi-crystalline, high-molecular-weight PEEK chains
This step is highly sensitive to moisture, temperature, and mixing speed. Any deviation may affect crystallinity and mechanical properties.
2. Pelletizing
The molten PEEK is:
- Extruded into strands
- Chopped into uniform pellets
- Thoroughly dried to remove residual solvents and moisture
These pellets are then ready for downstream processing such as injection molding, extrusion, or CNC machining.
3. Processing & Fabrication
PEEK pellets can be used in:
- Injection molding for complex shapes
- Extrusion for tubing, films, and profiles
- Machining for precision components, often in aerospace or medical
Some grades may also be reinforced or compounded during this stage (e.g. carbon-fiber-filled, lubricated types).
Leading Global PEEK Manufacturers
Due to the complexity and purity requirements, PEEK production is dominated by a few specialized chemical companies worldwide:
| Manufacturer | Brand/Grade | Country/Region | Remarks |
|---|---|---|---|
| Victrex plc | VICTREX® PEEK | United Kingdom | Global leader, medical and industrial focus |
| Solvay | KetaSpire® PEEK | Belgium/USA | Wide product range, aerospace and electronics |
| Evonik | Vestakeep® PEEK | Germany | Strong in medical and high-temperature grades |
| ZYPEEK (Jilin Joinature) | ZYPEEK® | China | Largest PEEK supplier in Asia |
| Pan Jin Zhongrun | Zhongrun PEEK | China | Growing presence in domestic and export markets |
These suppliers offer PEEK in various grades: virgin, reinforced, medical-certified, and food-safe.
What Is PEEK Used For?
PEEK is favored where pharmaceuticals, weight limits, or durability concerns intersect with performance demands.
| Industry | Typical PEEK Applications |
|---|---|
| Aerospace | Engine components, insulators, bearings, lightweight brackets |
| Automotive | Fuel-system parts, piston rings, transmission bushings, HVAC-bushing assemblies |
| Medical | Spinal cages, dental implants, surgical tools, sterilizable equipment |
| Electronics | Connectors, semiconductor handling tools, insulators |
| Oil & Gas | Seals, lateral pump components, valve parts |
| Industrial | Wear pads, bearings, bushings, compressor components |
| Energy | Valve seats and pump parts in renewable energy systems |
PEEK bridges the gap between metals and traditional plastics in demanding roles.
Now, as humanoid robots become more advanced and widely adopted, PEEK is emerging as a key material for high-load, high-precision components.
Several robotics companies have adopted carbon-fiber reinforced PEEK or lubricated PEEK to improve performance at high cycle counts—critical in robotics.
With humanoid robots expected to play roles in healthcare, logistics, and service sectors, PEEK’s presence in this industry is set to grow rapidly.
How Does PEEK Compare to Other High-Performance Polymers?
Choosing materials requires balancing performance and cost. Here’s how PEEK compares to others:
| Property | PEEK | PEI (Ultem) | PPS | PTFE |
|---|---|---|---|---|
| Temperature (°C) | 250–300 | 170–200 | 180–200 | 260 |
| Tensile Strength (MPa) | 90–100 | 110–130 | 50–70 | 20–30 |
| Chemical Resistance | Excellent | Very good | Good | Excellent |
| Wear Resistance | Excellent | Good | Fair | Good |
| Machinability | Good | Good | Moderate | Poor |
| Biocompatibility | Excellent | Good | Fair | Excellent |
| Cost | High | Medium-high | Medium | High |
What the Table Tells Us:
PEEK vs PEI: Ultem (PEI) has higher tensile strength and lower cost, but lower temperature resistance. PEI works well in enclosures and structural parts where extreme heat is not an issue.
PEEK vs PPS: PPS is more affordable and still performs well in chemical resistance and heat. However, its mechanical strength and wear performance are inferior—less suitable for load-bearing parts.
PEEK vs PTFE: PTFE has unmatched chemical resistance and slipperiness, but it’s too soft and hard to machine. PEEK is better for structural applications requiring precision.
PEEK is a strong choice when your application requires a balance of mechanical strength, thermal stability, and wear resistance—especially in demanding environments like aerospace, medical devices, or robotics.
If cost is a concern, PEI or PPS may serve as suitable alternatives depending on specific conditions.
How to Select a PEEK Grade
PEEK is not a one-size-fits-all material. It comes in multiple grades—each tailored for specific performance needs, environments, or regulatory requirements.
Common PEEK Grades and Their Applications
| Grade | Key Features | Typical Applications |
|---|---|---|
| Virgin PEEK | Highest purity, no fillers or additives | Medical implants, aerospace parts, precision CNC |
| Glass-filled PEEK | ~30% glass fiber; increases stiffness (up to 7 GPa) | Structural brackets, pump housings, electronic frames |
| Carbon-filled PEEK | High dimensional stability and wear resistance | Bearings, robotic joints, compressor components |
| Oil-filled PEEK | Internally lubricated; reduces friction and wear | Self-lubricating bushings and bearings |
| Medical/Cleanroom | Meets USP Class VI or ISO 10993 biocompatibility | Surgical tools, medical housings, diagnostic devices |
| FDA/Food-contact | FDA and EU compliant for food environments | Food processing equipment, beverage filling systems |
| High-temperature grades | Enhanced thermal resistance >300°C | Semiconductor tools, high-heat industrial settings |
Tip: Reinforced grades (glass/carbon-filled) offer better mechanical stability, but lower elongation and may be harder to mold.
PEEK Grade Selection Checklist
When choosing a PEEK grade for your project, consider:
- Mechanical load & thermal stress
– Will the part bear heavy loads or operate near motors or heat sources? - Friction and wear demands
– Will the component move or rotate frequently? Choose wear-resistant or lubricated types. - Environmental and chemical exposure
– For corrosive or sterile environments, virgin or medical-grade PEEK may be essential. - Regulatory compliance
– Does your part require FDA, ISO 10993, or cleanroom certification? - Processing method
– Virgin PEEK is easier to mold; filled types may be better suited to machining. - Budget vs performance
– High-performance grades come at a premium—assess ROI based on part function.
If you’re not sure which grade fits your application, contact our engineers for technical guidance.
What Are Future Trends in PEEK?
PEEK continues evolving as technology demands grow:
- Advanced composites – Nano fillers for improved conductivity, strength, or barrier properties.
- Bio-based PEEK – Research in using renewable feedstocks is gaining traction.
- Additive manufacturing – Fiberglass and carbon-fiber reinforced PEEK are becoming more common in high-performance 3D printing.
- Medical expansion – Customized implants and patient-specific devices.
- Electrification & energy – Bigger roles in battery insulation, EV parts, and solar panel mounts.
Market forecasts estimate CAGR between 7–9% through 2030, especially in aerospace, medical, and EV sectors.
Summary
PEEK is a top-tier, semi-crystalline engineering plastic known for exceptional heat tolerance, mechanical strength, and chemical resistance. It’s a premium alternative to metal in performance-critical applications. Selecting an appropriate grade and processing method ensures reliability and value—even at higher material cost.
Need help choosing or machining PEEK? We offer CNC machining and injection molding services for short runs or production volumes. Contact our team for a tailored consultation and fast quote.
