Curious about how to assess or enhance the thermal conductivity of PEEK for your next project? Whether you’re designing high-performance components or ensuring efficient heat management, understanding PEEK’s thermal properties can make all the difference.
This article breaks down exactly what thermal conductivity means for PEEK, why it matters, and how to measure or potentially improve it. Get clear, practical steps and expert tips to guide your decisions and optimize your results.
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What Is the Thermal Conductivity of PEEK?
Polyether ether ketone (PEEK) is a high-performance engineering thermoplastic valued for its excellent mechanical and thermal properties. When discussing how well a material can transfer heat, the key property is its thermal conductivity.
PEEK typically has a thermal conductivity of approximately 0.25 W/m·K (Watts per meter-Kelvin). This value means PEEK is considered a thermal insulator compared to metals. While PEEK can withstand high temperatures and harsh environments, it does not conduct heat efficiently. That’s both a limitation and a benefit, depending on your application.
Breaking Down PEEK’s Thermal Conductivity
Let’s explore what this property really means—and why it matters for you.
Understanding Thermal Conductivity in Simple Terms
Thermal conductivity tells you how easily heat flows through a material. It is measured in watts per meter per Kelvin (W/m·K).
- High thermal conductivity: Means heat passes through more easily (think metals like copper).
- Low thermal conductivity: Means the material resists heat flow (think materials like wood, rubber, or many plastics).
With its value around 0.25 W/m·K, PEEK is a poor conductor of heat. This is typical for most plastics but is particularly notable when considering applications that may involve high temperatures.
Why Thermal Conductivity of PEEK Matters
When selecting materials for engineering projects, especially in aerospace, electronics, medical devices, or automotive, it’s crucial to know how your chosen plastic handles heat.
Benefits of Low Thermal Conductivity in PEEK
- Thermal Insulation:
- PEEK can act as a barrier, reducing heat transfer in sensitive electronic assemblies.
- Component Protection:
- Helps protect other parts of an assembly from heat, preserving their function and extending lifetime.
- User Safety:
- Reduces the risk of burns or heat-related injuries if the component will be handled.
Potential Disadvantages
- Heat Accumulation:
- In situations where heat needs to be removed quickly (like heat sinks), PEEK is not the best choice alone.
- Design Complexity:
- May need additional design features, such as heat sinks or active cooling.
Comparing PEEK’s Thermal Conductivity with Other Materials
Here’s a quick look at how PEEK stacks up against common materials:
| Material | Approx. Thermal Conductivity (W/m·K) |
|---|---|
| PEEK | ~0.25 |
| PTFE (Teflon) | ~0.25 |
| Nylon | ~0.25 – 0.30 |
| Polycarbonate | ~0.20 |
| Aluminum | ~205 |
| Copper | ~385 |
| Glass | ~0.8 |
As you can see, PEEK’s thermal conductivity is typical for plastics—considerably lower than metals or even certain glass types.
Factors Influencing PEEK’s Thermal Conductivity
While the baseline is about 0.25 W/m·K, this value isn’t set in stone. Several variables can affect the specific thermal conductivity of the PEEK material you use:
- Fillers:
- Adding fillers like glass fibers or carbon fibers can increase PEEK’s thermal conductivity.
- Crystal Structure:
- Crystalline regions in PEEK conduct heat slightly better than amorphous (disordered) regions.
- Processing Conditions:
- How the material is molded or extruded can influence its density and structure, affecting conductivity.
- Temperature:
- PEEK’s thermal conductivity slightly increases as the temperature rises, but not dramatically.
Applications Leveraging PEEK’s Thermal Properties
PEEK is chosen specifically for its combination of stability, thermal resistance, and low conductivity. Here are some common usage scenarios:
- Medical Devices:
- Insulates delicate electronics from body temperature or sterilization processes.
- Aerospace & Automotive:
- Protects sensitive sensors and wiring from engine or environmental heat.
- Semiconductor Manufacturing:
- Maintains stable performance near hot processing equipment.
- Electrical & Electronic Components:
- Used as insulators, cable sheaths, and circuit board supports.
Enhancing PEEK’s Thermal Conductivity
What if you need PEEK’s strength but more efficient heat transfer? It’s possible to modify standard PEEK in a few ways:
Adding Fillers
- Carbon Fiber-Reinforced PEEK:
- Addition of carbon fibers can boost thermal conductivity up to 10 times, reaching values around 1–5 W/m·K.
- Glass Fiber-Reinforced PEEK:
- Adds some thermal improvement but less than carbon fibers, typically up to ~0.5 W/m·K.
Metal-Coated PEEK
- Applying a thin metal layer to PEEK components can improve surface heat dissipation without losing PEEK’s structural benefits.
Blends and Composites
-
Manufacturers sometimes blend PEEK with other polymers or ceramics for tailored conductivity.
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Tip:* If high thermal conductivity is crucial, always specify the type of PEEK and the percentage/type of filler you require.
Best Practices for Using PEEK Where Thermal Conductivity Matters
Here’s how to get the most out of PEEK when managing heat is part of your project:
- Define the Thermal Load:
- Calculate how much heat your part will encounter.
- Choose the Right Grade:
- For better conductivity, ask for carbon- or graphite-filled PEEK.
- Design for Heat Management:
- Use heat sinks, cooling fins, or ventilation as needed if heat build-up is a concern.
- Layer Wisely:
- Combine PEEK with conductive layers or inserts if needed.
- Test Your Designs:
- Always prototype and measure actual temperature changes under real conditions.
Cost Tips When Sourcing PEEK Materials
PEEK is a premium engineering plastic, which means it can be costly compared to commodity plastics. When cost is a factor, especially including shipping, keep these points in mind:
- Bulk Purchasing:
- Ordering in larger quantities can reduce per-unit cost and shipping charges.
- Local Suppliers:
- Whenever possible, buy from domestic distributors to avoid high international shipping fees.
- Filled Grades:
- Specialty PEEK (such as carbon-filled) is more expensive than unfilled. Balance property gains against increased costs.
- Scrap and Waste:
- Plan cuts and machining carefully—wasting PEEK is costly.
- Compare Suppliers:
- Request quotes from multiple suppliers and factor in shipping, taxes, and possible custom fees.
Frequently Asked Questions (FAQs)
What is the typical thermal conductivity of unfilled PEEK?
Unfilled PEEK usually has a thermal conductivity of about 0.25 W/m·K. This makes it a very effective thermal insulator compared to metals or certain ceramics.
Can PEEK’s thermal conductivity be increased for special applications?
Yes, by adding fillers such as carbon fiber or graphite, PEEK’s thermal conductivity can be increased to about 1–5 W/m·K depending on the filler type and content.
Is PEEK suitable for heat sink applications?
Standard PEEK is not ideal for heat dissipation or heat sink roles due to its low thermal conductivity. Filled or composite grades can perform better, but metals are still superior for these uses.
Does PEEK’s thermal conductivity change significantly with temperature?
PEEK’s thermal conductivity does increase slightly with temperature, but the change is not dramatic. It remains substantially lower than metals across typical industrial temperature ranges.
Is PEEK more expensive than other thermoplastics, and does thermal conductivity affect price?
PEEK is generally more expensive than most common plastics due to its high-performance characteristics. Filled grades (which may have higher conductivity) are even costlier, but the difference in price is more due to added materials than the property itself.
In Summary
PEEK’s thermal conductivity is quite low, positioning it as an excellent insulator among engineering materials. Its strength, thermal resistance, and stability make it ideal for parts exposed to high temperatures, especially where you don’t want heat to move around quickly. If your application needs more heat transfer, consider filled or composite PEEK grades, or design to include additional heat-removing features.
Before committing, always review your project’s heat management needs and consult with material experts or suppliers to select the right PEEK type. Balancing material performance, cost, and shipping considerations will help you get the best results for your application.