Elastomers vs Engineered Plastics

Material Selection Defined by Application Requirements

Material selection is not a matter of simply choosing between elastomers and engineered plastics.

It is about aligning material properties with the specific demands of the application. This includes sealing performance, wear characteristics, temperature range, chemical compatibility, and load requirements.

At ESP, we evaluate elastomers and engineered plastics against your application requirements to ensure optimal performance. This process clarifies the most suitable material solution for your system.

Why Material Selection Gets Complicated

In real applications, performance is driven by trade-offs:

• Sealing force vs. wear resistance
• Flexibility vs. dimensional stability
• Chemical compatibility vs. mechanical strength
• Temperature limits vs. lifecycle performance

There is no universal best material; only the material that meets the specific requirements of the application.

Uncertainty often results from oversimplifying what is inherently a complex engineering decision.
Our role is to provide the technical clarity needed to make informed material choices.

Soft where it seals: Where Elastomers Perform

Elastomers are used where sealing energy and compliance are required.

• Conform to mating surfaces
• Maintain sealing contact under pressure and motion
• Absorb tolerances and installation variation
• Enable reliable sealing in static and dynamic conditions

Common Applications

• O-rings and gaskets
• Lip seals and shaft seals
• Diaphragms and valve seals

In many engineered systems, elastomers serve as the primary sealing interface, selected for their compliance and ability to maintain contact under varying conditions.

Hard where it supports: Where Engineered Plastics Matter

Engineered plastics are specified where structural support, wear resistance, and dimensional stability are critical to system performance.

• Resist wear, abrasion, and friction
• Maintain shape under load and pressure
• Perform in elevated temperatures
• Handle aggressive chemical environments

Common Applications

• Wear rings and guides
• Bushings and bearings
• Valve seats and backup rings
• Structural and support components

Material Selection: Driven by Application Requirements

Some systems are elastomer-based.
Some are plastic-based.
Many use both.

The determining factor is not the material itself, but the application's operational and regulatory requirements.

At ESP, we evaluate:

• Temperature range
• Media / chemical exposure
• Motion (static, rotary, reciprocating)
• Load and pressure conditions

Based on this evaluation, we recommend:

• Elastomer solution
• Polymer solution
• Or a combined approach

Elastomers and engineered plastics are specified to align with your application’s requirements.

Where ESP Adds Value

ESP is not built around selling a material category.

We focus on:

• Application-first material selection
• Balancing sealing performance and durability
• Identifying and evaluating trade-offs proactively to mitigate risk before failure occurs
• Supporting both elastomer and engineered plastic solutions

Request a Material Review

Start with one component.

If you have a part that:

• Wears prematurely
• Loses sealing performance
• Experiences temperature or chemical limitations
• Requires frequent replacement

Send:

• Part or drawing
• Operating conditions (temperature, media, motion, load)

You’ll get:

• Recommended material options
• Trade-offs and considerations
• Clear guidance on next steps

Submit a Part for Review

Frequently Asked Questions

What is the difference between elastomers and engineered plastics?

Elastomers are flexible materials used for sealing and compression, while engineered plastics are rigid or semi-rigid materials used for structural support, wear resistance, and stability.

They are often applied together or selected based on specific application requirements.

When should you use PTFE or PEEK instead of rubber?

Engineered plastics such as PTFE or PEEK may be considered when:

• Higher temperature resistance is required
• Chemical exposure exceeds elastomer limits
• Wear or friction drives failure

However, elastomers are often still required for sealing force.

Can engineered plastics replace elastomer seals?

In most cases, no.

• Plastics support performance in specific conditions
• Elastomers typically provide the sealing interface

Material selection depends on the application—not substitution.

How do you choose between elastomers and plastics?

Material selection is based on:

• Temperature
• Chemical exposure
• Motion type
• Load / pressure
• Required performance

These factors determine whether elastomers, engineered plastics, or both are appropriate.