PPS vs. PEEK: Which Should You Choose?

PPS and PEEK are both semicrystalline, high-performance thermoplastics. They’re known broadly for low friction, good wear, fatigue, and chemical resistance.

Because these two plastics appear so similar, property-wise, it can be hard to know which is best to use for your next engineering project or client-sourcing job. Whether a manufacturing engineer or a materials manager, you need to know your plastics. Understanding the difference between PPS vs. PEEK can help you save money and timeno matter what industry you’re in. Read on to learn about PEEK and PPShow they differ, their similarities, and their pros and cons.

What Is PPS?

When deciding between PEEK vs. PPS, it’s beneficial to look at each material independently. PPS is the abbreviation of polyphenylene sulfide. It’s widely used in the industry in place of the long chemical name for obvious reasons. It was first developed by Philips Petroleum employees Dr. H. Wayne Hill Jr. and James T. Hill, who filed the patent in 1967. Depending on who manufactures the material, it might also be known by one of the various tradenames available in the marketplace today.

It’s one of the most popular high-temperature thermoplastic polymers due to its relatively low cost, ease of use, and desirable properties. You’ll find PPS in everything from seals and valves to medical devices and home storage containers. It’s typically available for purchase in sheet, rod, or tube form, depending on the needed applications. It’s also available as fiber for textiles.

What Are the Pros and Cons of PPS?

PPS has numerous benefits for many projects, especially where high temperatures are involved. However, there are also a few downsides to this revolutionary material.


PPS is flame resistant at thicknesses of 0.8 mm or less without adding chemical flame retardants. This means it can be lower cost (due to fewer material requirements) than other flame retardant formulations like PA and PCeven when balanced against their better mechanical strength.

PPS also boasts a substantially low water absorption rate. This lack of absorption deformation ensures a low defect rate, lowering costs on the production end.

If you’re working with injection molding, PPS is an attractive material. Its ultra-high liquidity (resulting in high fluidity) and lower viscosity result in a more robust end-product that’s faster to produce.

Regarding visual properties, PPS products have a mirror-smooth surface and unique metallic luster. Unusually, they may even sound like metal when struck.


Now that you’ve run through the benefits of PPS, it’s time to consider the disadvantages. While it may seem like a “wonder material,” there are some drawbacks you need to considerdepending on the application.

It is challenging to add pigment to PPS, meaning you’ll only be able to work with dark colors, such as various shades of brown. (In its pure, solid form, it’s usually available in light tan to opaque white.) It has the propensity to develop notches and low tracking resistance.

What Is PEEK?

PEEK stands for polyether ether ketone. Like PPS, this colorless manufactured material is an organic semicrystalline thermoplastic polymer.

It is especially prized for its ability to retain its essential and beneficial properties at high temperaturesit won’t melt until environmental temperatures reach approximately 662 °F.

These properties include an excellent Young’s modulus, a high tensile strength, and good thermal, moisture, and environmental degradation resistance. This durability means PEEK is used extensively in engineering applications, including:

  • Fabrication of pistons, pumps, valves, insulation, HPLC columns, and bearings
  • Ultra-high vacuum environments
  • Aerospace industry
  • Automotive industry
  • Chemical processing industry

It’s often used in environments where steam or hot water is prevalent.

PEEK is also readily machinable and well-suited to injection molding. Like PPS, it’s known commercial under various tradenames and is available for purchase in PEEK rods, sheets and plates, and tubes.

It can also be easily modified; unique grades are availablefor example, fiber-reinforced PEEK or conductive PEEK.

What Are the Pros and Cons of PEEK?

PEEK is similar to PPS when it comes to plastic machining. However, it has some distinct properties you must be aware of before deciding between these equally sturdy materials.


One of the most sought-after beneficial properties of PEEK is its high heat resistance. It doesn’t melt until the temperature reaches well over 600 °F.

Outside of heat resistance, it also boasts outstanding mechanical properties, including:

  • High dimensional stability
  • Adequate bending and compressive strengths
  • High rigidity
  • A low coefficient of linear expansion
  • Good creep and stress resistance

In fact, many of PEEK’s properties are almost on par with aluminum! However, unlike its metal counterparts, only concentrated sulfuric acid will dissolve this durable plastic.

PEEK is also naturally flame retardant and radiation resistant, works continuously in wet environments, and performs well in electrical environments. It’s tough, friction and wear-resistant, and easy to process.


After reading the pros of this material, you might be thinking, “Are there any downsides at all?” One of the main drawbacks of PEEK is that it is complex and, therefore, costly to manufacture. This means it might not fit your budget.

It also lacks the thermoformability of PPS. In other words, it needs to be processed at high temperatures. Finally, it begins to degrade when exposed to UV light.

PPS vs. PEEK: Which is Best for Your Project?

The PPS vs. PEEK debate is challenging for engineers and buyers because many of their qualities overlap.

They can both endure high temperatures and are mechanically tough. Neither can be used as an electrical insulator. However, PEEK is incrementally more chemically inert than PPS.

If you’re unsure which material is suitable for your project, contact our expert team to discuss your needs. Severna Operations has been in the plastics machining and manufacturing business for over 70 years. We’re renowned across America for supplying custom precision plastics with the highest standard of quality.


David Taylor Digital | Digital Marketing Agency