Guide to material selection for high-performance plastics

High-performance plastics are used where standard plastics and many engineering plastics reach their thermal, mechanical or chemical limits. They are used, among other things, for highly stressed components, high operating temperatures, aggressive media, electrical applications and particularly demanding industrial environments.

But which high-performance plastic is suitable for which application?

For material selection, you should not look at individual characteristic values alone. Temperature, mechanical load, media contact, wear, dimensional stability, manufacturing processes and possible approvals must be assessed together.

High-performance plastics are also referred to as high-performance polymers. The well-known materials in this group include PEEK, PPS, PEI, PPSU and PAI. Depending on the requirement, materials such as PTFE or PVDF can also represent a suitable solution.

Which high-performance plastic is suitable for which requirement?

An initial pre-selection can be made based on the most important operating conditions:

Requirement	Materials for pre-selection
high continuous service temperatures	PEEK, PPS, PAI, PI
high chemical resistance	PTFE, PEEK, PVDF, PPS
high mechanical load capacity	PEEK, PAI, PPS
high dimensional stability	PEEK, PPS, PEI
sterilizability	PEEK, PPSU
low friction and good sliding properties	PTFE, suitable modified high-performance plastics
electrical insulation	PEI, PEEK, PPS
demanding industrial components	PEEK, PPS, PEI, PAI

This overview serves as initial guidance. For the actual material selection, the specific operating conditions of your application must be taken into account.

The most important criteria when selecting high-performance plastics

1. Determine operating temperature

Temperature resistance is one of the most important criteria when selecting a high-performance plastic.

You should not consider only the maximum short-term temperature. The following are particularly relevant:

• continuous operating temperature
• short-term temperature peaks
• temperature changes
• mechanical load at elevated temperature
• contact with media at elevated temperature

A material can have very good mechanical properties at room temperature and partially lose them at higher temperatures.

If temperature resistance is the central selection criterion for your application, you will find further information on our page on high-temperature plastics.

2. Analyse mechanical load

For mechanically stressed components, you should clarify which types of load the material is permanently exposed to.

These include, for example:

• tensile load
• compressive load
• bending
• impact stress
• surface pressure
• creep load
• alternating or dynamic loads

PEEK and PAI, for example, are often considered when high mechanical strength and temperature resistance must be combined.

In addition to pure strength, however, stiffness, toughness and the long-term behaviour of the material also play an important role.

3. Check chemical resistance

When in contact with chemicals, it is not enough to look only at the name of the medium.

For a reliable material selection, you should take into account, among other things:

• type of medium
• concentration
• operating temperature
• contact duration
• mechanical load during media contact
• possible combination of different chemicals

Materials such as PTFE, PEEK, PVDF and PPS are characterised by high chemical resistance to numerous media. However, the specific suitability must always be tested under the actual operating conditions.

4. Take friction and wear into account

For bearings, guides, sliding elements and other moving components, friction and wear properties are particularly relevant.

You should take into account, among other things, the following factors:

• sliding speed
• surface pressure
• counterface partner
• lubrication
• operating temperature
• contamination
• dry running

PTFE, for example, has very good sliding properties. For higher mechanical requirements, modified high-performance plastics can also be considered.

Further information on suitable materials can also be found in the article on self-lubricating plastics.

5. Assess dimensional stability and tolerances

For precise components, not only the strength of the material is relevant.

The following properties also influence dimensional accuracy:

• thermal expansion
• moisture absorption
• temperature changes
• internal stresses
• creep behaviour
• machining and manufacturing processes

For components with tight tolerances, you should take these properties into account already during material selection.

6. Define electrical requirements

High-performance plastics are also frequently used for electrical and electronic applications.

Depending on the component, the following properties can be relevant:

• electrical insulation
• dielectric strength
• dielectric properties
• surface resistance
• tracking resistance
• temperature resistance

PEI, PEEK and PPS are among the materials that can be of interest for various electrical applications.

For industry-specific requirements, you will find further information under plastics for the electrical industry.

7. Take approvals and industry requirements into account

Depending on the field of application, additional regulatory requirements may apply.

These can include, for example:

• requirements for food contact
• medical applications
• biocompatibility
• requirements for fire behaviour
• electrical standards
• industry-specific approvals

Not every material type automatically has the same approvals. What is relevant is therefore always the specific material type and not exclusively the polymer family.

High-performance plastics in comparison

The following overview shows typical properties of various high-performance plastics and related materials.

Material	Temperature resistance	Chemical resistance	Mechanical properties	Typical fields of application
PEEK	very high	very high	very high	mechanical engineering, medical technology, electronics, demanding construction parts
PPS	high	very high	high	industry, electronics, chemically stressed components
PEI	high	good	high	electrical applications, technical components
PPSU	high	good	high and impact-resistant	medical technology, sterilizable components
PAI	very high	good	very high	precision parts subject to high mechanical and thermal stress
PI	very high	material-dependent	very high	extreme thermal applications
PTFE	high	excellent	comparatively lower stiffness	seals, sliding components, chemically stressed applications
PVDF	high	very high	good	chemical industry, plant engineering and fluid technology

The actual properties can vary depending on the material type, filler, reinforcement and manufacturer. For selection, the specific material data should therefore always be checked.

PEEK: for high mechanical and thermal requirements

PEEK plastic is one of the best-known high-performance plastics.

The material combines, among other things:

• high temperature resistance
• high mechanical strength
• high stiffness
• good wear properties
• very good chemical resistance
• good dimensional stability

PEEK is therefore suitable for demanding components where several high requirements must be met simultaneously.

However, the material is not automatically the most economical or technically best solution for every application. If, for example, mainly high chemical resistance is required, other plastics may be more suitable.

PPS: high chemical resistance and dimensional stability

PPS plastic offers a combination of good temperature resistance, high chemical resistance and high dimensional stability.

The material is therefore used, among other things, for technical components that are permanently exposed to higher temperatures and aggressive media.

Particularly in applications where high dimensional accuracy is required, PPS can represent an interesting alternative to other high-performance plastics.

PEI and PPSU: high-performance plastics for special requirements

PEI plastic offers good mechanical, thermal and electrical properties and can be used, for example, for electrical or technical construction parts.

PPSU plastic is characterised in particular by high impact resistance and good resistance to repeated sterilisation processes. As a result, the material is suitable, among other things, for applications in medical and laboratory technology.

PAI and polyimides for extreme loads

PAI plastic and polyimides are among the materials for particularly demanding thermal and mechanical operating conditions.

PAI can offer very high mechanical strength, stiffness and wear resistance.

Polyimides are used in particular when very high temperatures and special technical requirements come together.

Due to their properties and costs, these materials are usually used very specifically for applications where more conventional engineering plastics are no longer sufficient.

PTFE and PVDF under high chemical stress

Not every application requires maximum mechanical strength.

When high chemical resistance is the priority, PTFE and PVDF can represent interesting alternatives.

PTFE is characterised by an exceptionally broad chemical resistance as well as very good sliding properties.

PVDF combines high chemical resistance with good mechanical properties and is frequently used for components in chemical plant engineering and in fluid technology.

High-performance plastics and high-performance polymers: is there a difference?

The terms high-performance plastics and high-performance polymers are frequently used in practice for the same group of materials.

What is meant are plastics that can also be used under particularly high thermal, mechanical, chemical or electrical loads.

Internationally, the term "High Performance Polymers" or "High Performance Plastics" is frequently used.

However, no fully uniform definition exists. What is relevant is therefore less the designation of the material group than the specific property profile of the respective material.

An overview of the available materials can be found on our page on high-performance plastics.

How to proceed with material selection

A systematic material selection reduces the risk of using a technically unsuitable or unnecessarily expensive material.

It is best to proceed in this order:

1. Define the minimum and maximum operating temperature.
2. Determine the mechanical loads that occur.
3. Record all media and chemicals with which the component comes into contact.
4. Check requirements for friction and wear.
5. Define the required tolerances and the desired dimensional stability.
6. Take electrical requirements into account.
7. Check necessary approvals and industry-specific specifications.
8. Determine the suitable manufacturing process.
9. Then compare several technically suitable materials with one another.

The available semi-finished product form should also be taken into account early. Martan Plastics offers various plastic semi-finished products, from which components can be manufactured according to the respective requirements.

In this way, the selection can be narrowed down step by step instead of committing early to a single high-performance plastic.

Also take machining into account during material selection

The properties of a material alone are not sufficient for selection. The planned manufacturing process must also match the material, the geometry, the quantity and the required tolerances.

During plastic machining, for example, heat generation, internal stresses, tool geometry and clamping technology can influence the dimensional accuracy of the finished component.

Depending on the material and geometry, CNC milling, CNC turning, drilling, sawing or other processes can be considered, among others. Particularly with high-priced or fibre-reinforced high-performance plastics, machining should be taken into account already during material selection.

Why the most expensive high-performance plastic is not automatically the best

When selecting a material, you should not choose the highest-performance material, but the material that reliably fulfils the requirements of your application.

A material with extremely high temperature resistance, for example, offers no additional technical benefit if the component is used exclusively at moderate temperatures.

At the same time, costs must not be considered in isolation. A suitable high-performance plastic can, for example:

• extend the service life of a component
• reduce maintenance intervals
• save weight
• avoid corrosion problems
• reduce lubrication
• replace metal components
• make additional coatings unnecessary

A good material selection therefore always considers technical properties, manufacturing and total costs together.

Particularly in mechanical and plant engineering, high-performance plastics can therefore represent an interesting alternative to conventional materials.

Frequently asked questions about selecting high-performance plastics

What are high-performance plastics?

High-performance plastics are plastics for particularly demanding thermal, mechanical, chemical or electrical operating conditions. Examples are PEEK, PPS, PEI, PPSU, PAI and polyimides.

What are high-performance polymers?

High-performance polymers is an alternative designation for high-performance plastics. In English, the terms High Performance Polymers or High Performance Plastics are frequently used.

Which high-performance plastic is particularly temperature-resistant?

PAI, polyimides and PEEK are among the materials that can be used for high thermal loads. However, which plastic is suitable also depends on load, media contact and operating duration.

A cross-material overview can be found under high-temperature plastics.

Which high-performance plastic is particularly chemical-resistant?

PTFE, PEEK, PVDF and PPS have high resistance to numerous chemicals. Suitability must always be checked based on the specific medium, the concentration and the operating temperature.

When does PEEK make sense?

PEEK is particularly interesting when high temperature resistance, mechanical strength, chemical resistance and dimensional stability are required simultaneously.

What is the difference between engineering plastics and high-performance plastics?

Engineering plastics cover many industrial applications. High-performance plastics are used when higher thermal, mechanical, chemical or electrical requirements exist that cannot be reliably met with more conventional engineering plastics.

An overview of the available materials can be found in the materials section.

How do I find the right high-performance plastic?

First define the operating conditions of your application. These include temperature, mechanical load, chemical contact, friction, tolerances, approvals and manufacturing processes. Suitable materials can then be compared with one another based on these criteria.

Support in selecting the right high-performance plastic

The selection of a high-performance plastic should always be based on the actual operating conditions of your component.

Temperature, mechanical load, chemicals, tolerances, manufacturing processes and economic requirements together influence which material is suitable.

Martan Plastics supports you in selecting suitable high-performance plastics, choosing suitable plastic semi-finished products and the subsequent plastic machining. In this way, it is possible to check already in an early project phase which materials and manufacturing processes are technically and economically sensible for your application.

If you already have a drawing, details on temperature and load or information on the material previously used, you can submit these directly via the enquiry to Martan Plastics.