by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Polymer Seals for Electrified Systems: Managing Heat, Voltage, and Friction

Designing Polymer Seals for Electrified Systems: Managing Heat, Voltage, and Friction

The ability do design polymer seals for electrified systems is vital in modern engineering. The current shift toward electrified systems, whether in EV drivetrains, aerospace actuators, or high-voltage power converters, means that engineers must transform how they think about sealing. Traditional seal design focused on pressure and fluid compatibility. Electrified systems however, add three new variables: electrical conductivity, insulation integrity, and heat dissipation.

The wrong choice of polymer can lead to arcing, insulation breakdown, or premature wear, while the right one can enhance reliability and extend component life. This blog post is going to explore how seal designers can manage heat, voltage, and friction for electrified systems.

Polymer Seals for Electrified Systems

Electrified systems subject seals to hybrid stresses: electrical, thermal, and mechanical. Thermal gradients develop near conductive components, especially in high-current zones or power-dense assemblies. Electrostatic fields and stray currents can compromise material integrity, accelerating degradation. Mechanical wear and vibration persist just as they do in traditional systems—but the allowable frictional losses are often much lower.

Different applications bring unique sealing demands. In electric traction motors, for example, shaft seals must prevent the ingress of coolant while also blocking stray currents. DC/DC converters, meanwhile, are in need of seals that double as dielectric barriers.

Balancing Dielectric and Thermal Properties for Polymer Seals for Electrified Systems

Polymers in electrified systems must play a dual role: insulate against high voltage while managing heat generated in compact assemblies. They key properties involved in designing polymer seals for electrified systems include dielectric strength, thermal conductivity, and wear rate, all of which determine seal performance and longevity.

Common polymer choices include:

  • PTFE is chemically inert, possess excellent dielectric strength, and exhibits ultra-low friction, making it ideal for high-speed, low-load applications.
  • PEEK has high mechanical strength and temperature capabilities, meaning it can tolerate heavier loads but at the cost of slightly higher friction.
  • PPS and UHMW-PE are cost-effective options that combine good dielectric resistance with moderate wear performance.
  • Filled compounds (carbon, graphite, glass) are used to enhance wear and sometimes conductivity, though they may reduce dielectric performance.

Creep resistance, thermal aging, and the ability to maintain integrity across temperature extremes all influence selection. In many cases, designers use blended materials or layered seal architectures to balance insulation with heat dissipation.

Managing Heat

Electrified systems are going to generate localized hotspots located near bearings, windings, and current-carrying seals. Without appropriate heat management, polymers can easily soften, creep, or degrade. Effective seal deisgn for electrified system design requires careful consideration of factors such as thermal pathways, geometry, and material stability.

Thin cross-sections, for example, help to minimize thermal buildup ,but must still resist extrusion issues. Conductive fillers or metal housings can help spread heat away from the seal interface. Engineers must also account for the glass transition temperature of materials, their continuous-use temperature, and their oxidation resistance.

Heat cycling has a major influence on seal preload and spring energizers. In EV cooling pumps, for example, repeated swings from –40°C to 150°C demand highly resilient fluoropolymers and careful thermal expansion matching between the seal and shaft.

Managing Voltage

Seals can be damaged by electrical stress over time. Potential issues include dielectric breakdown, corona discharge, and surface tracking can —  all of which lead to performance loss or catastrophic failure.

Engineers can mitigate these issues through material and design strategies such as:

  • Choosing polymers with a high dielectric strength (PTFE, PEEK, PPS)
  • Using conductive fillers to safely dissipate charge buildup.
  • Designing surface contours and creep distances that reduce the risk of arcing 
  • Grounding components to divert stray currents away from sealing interfaces

Managing Friction

Friction directly affects energy efficiency, thermal load, and component life. In electrified systems, even a small amount of frictional increase can have a significant impact on range of performance. 

Designers must strike a careful balance between low friction and effective sealing contact. Surface finish, lubrication strategy, and seal geometry all play a part, and spring-energized PTFE seals are often chosen for their low-leak, low-drag characteristics.

Because many electrified systems operate in dry or low-lubrication conditions, polymers with intrinsic lubricity or dry-film coatings are critical. Comparing dry-film lubricants, filled PTFE blends, and hybrid polymer systems helps determine which approach provides the best combination of sealing and efficiency.

System-Level Integration—The Interplay of Heat, Voltage, and Friction

Heat, voltage, and friction are not independent. Heat increases friction and reduces dielectric strength. High voltage accelerates wear through localized arcing. Frictional heating compounds both mechanical and electrical stress.

System-level analysis is, therefore, essential for engineers designing a successful polymer seal for electrified systems. Finite element analysis (FEA) can be used to model thermal and mechanical stresses, while electrical field modeling predicts voltage gradients across seal interfaces. 

By co-designing seals with their housings and integrating thermal barriers or conductive paths, engineers can significantly improve both the electrical safety and mechanical durability of seals for electrified systems.

Conclusion: Engineering Reliability in the Electrified Era

Electrification means that no longer is seal design just about blocking fluids or retaining pressure. These seals must manage a delicate balance between heat, voltage, and friction.

When properly designed, polymer seals do not just survive these stresses. They enable higher efficiency, longer service life, better range, and greater system reliability. In the electrified era, seal design is an exercise in electrical and mechanical synergy.

At Advanced EMC, our team of experts can help you find the right solution when designing polymer seals for electrified system. Contact us today to learn more.

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

How PTFE and PEEK Enable Reliable Sealing Across Extreme Media

In the world of advanced sealing, few materials can match the resilience and versatility of PTFE and PEEK. When systems operate at temperatures below –200 °C or handle chemicals capable of dissolving most polymers, seal failure is not an inconvenience—it’s a critical risk. In such environments, the combination of PTFE and PEEK enable reliable sealing performance that remains stable, predictable, and long-lived.

This blog post focuses on key features of PTFE and PEEK that make their sealing solutions a good choice for extreme media and reviews applications where these materials excel.

The Challenge of Sealing Across Opposing Extremes

Designing a seal for cryogenic and/or corrosive service is an exercise in contradiction. At extremely low temperatures, most polymers become brittle and lose their ability to conform to mating surfaces. Under high heat or chemical exposure, others swell, creep, or break down at the molecular level. Even metals typically  lack the elasticity or chemical resistance required for tight dynamic sealing.

True reliability comes from materials that can maintain their properties across this spectrum—retaining flexibility near absolute zero while withstanding oxidative and acidic environments at elevated temperatures. This is precisely where PTFE and PEEK excel.

PTFE: The Chemical Inertness Benchmark

Polytetrafluoroethylene (PTFE) serves ast the industry standard for chemical resistance and thermal stability. With its fully fluorinated carbon chain forms, PTFE is one of the most inert polymer molecular structures known. It is impervious to nearly all solvents, acids, and bases. Its operating range is from –250 °C to +260 °C, and PTFE is able to maintain low friction and minimal surface adhesion even in the harshest conditions.

In dynamic seals, its extremely low friction and self-lubrication allows results in lower torque, reduced stick-slip, and minimal wear against counterfaces. In addition, cryogenic engineers value PTFE’s ability to retain elasticity at temperatures that render most elastomers and many polymers extremely brittle. In chemical processing, it functions as a barrier material, protecting metallic components from corrosive attack.

However, unfilled PTFE has its limits. Under continuous load, it can creep or cold-flow, gradually losing preload. Engineers address this with fillers such as glass, graphite, carbon, or bronze, with each improving compressive strength and wear resistance. These modifications allow PTFE and PEEK enable reliable sealing designs to meet performance expectations in applications ranging from cryogenic valves to aggressive chemical reactors.

PEEK: Structural Integrity Under Pressure

Polyether ether ketone (PEEK) seems to complement the properties PTFE by offering exceptional mechanical strength and outstanding dimensional stability. Where PTFE provides chemical inertness, PEEK contributes structural endurance. Its semi-crystalline molecular structure gives it tensile strengths exceeding 90 MPa and excellent creep resistance maintained even at continuous temperatures approaching 250 °C.

In sealing systems, PEEK often serves as a backup ring, retaining element, or structural carrier for softer sealing materials. PEEK is excellent at resisting extrusion under high differential pressure and maintains shape when thermal cycling could otherwise deform conventional polymers. Chemically, PEEK withstands regular exposure to hydrocarbons, steam, and strong acids, thus making it indispensable in oil-and-gas and chemical processing environments.

Composite grades filled with carbon fiber, graphite, or PTFE further optimize tribological performance. These blends combine the toughness of PEEK with the low friction and self-lubrication of PTFE, thus ensuring smoother operation dynamic sealing solutions where where friction is critical.

PTFE and PEEK Performance Across Extreme Temperatures and Corrosive Media 

Engineers often use PTFE sealing solutions for operations that involve components, such as cryogenic hydrogen and oxygen valves, where lubrication must persist without freezing or outgassing. On the other hand, PEEK components dominate in high-temperature pumps and compressors exposed to sour gases, acids, or amine-laden fluids. 

Even in vacuum environments, PTFE’s extremely low outgassing helpts to ensure critical contamination-free operation. PEEK’s dimensional stability supports precise alignment and positioning even over extreme temperature ranges. Such mechaniacl properties can translate into longer service life, reduced maintenance cycles, and measurable operational cost savings, all of which are outcomes every engineer values.

Conclusion: Material Science at the Edge of Performance

When the operating conditions involve everything form cryogenic cold to corrosive heat, only a select group of polymers can deliver consistent performance: PTFE and PEEK. One offers unmatched chemical inertness and low friction; the other, exceptional mechanical integrity and pressure resistance. Working independently or in tandem, PTFE and PEEK enable reliable sealing in systems where failure is simply not an option.

For engineers designing valves, compressors, or actuators expected to survive the extremes, these two polymers represent more than material choices—they represent confidence. Through advanced formulations, precision machining, and innovative hybrid geometries, the limits of polymer sealing continue to expand.