High‑Performance Plastics for Sealing and Components: Comparing PTFE, PFA, PEEK and UHMWPE

Reliable seals and precision components are the backbone of modern machinery, whether they operate in cleanroom drug manufacturing, offshore drilling platforms or semiconductor fabrication plants. These parts must endure aggressive chemicals, high pressures, repeated mechanical cycles and wide temperature swings without losing their integrity. High‑performance plastics—materials with exceptional thermal stability, chemical resistance and mechanical strength—are often the best solution. Canyon Components not only supplies these materials in the form of O‑rings, gaskets and custom parts, but also has the expertise to help engineers choose and manufacture the right polymer for each application.

This article compares four leading high‑performance plastics used for sealing and machined components: polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), polyetheretherketone (PEEK) and ultra‑high molecular weight polyethylene (UHMWPE). Each polymer has unique properties that make it ideal for particular conditions. Understanding these differences can help you select the material that maximizes reliability, minimizes maintenance and meets regulatory requirements.

Key factors when choosing high‑performance plastics

When evaluating a plastic for seals or mechanical parts, engineers balance several performance factors:

• Temperature range: Maximum and minimum service temperatures determine whether a polymer can withstand hot fluids, steam sterilization, cryogenic storage or thermal cycling. PTFE and PFA can operate continuously up to around 260 °C (500 °F), while UHMWPE is limited to 80–160 °C depending on grade.
• Chemical resistance: Fluoropolymers like PTFE and PFA are nearly inert, resisting acids, bases and solvents. UHMWPE tolerates many chemicals but may degrade in strong oxidizers. PEEK is highly resistant to hydrocarbons, steam and many chemicals.
• Mechanical strength and wear resistance: PEEK excels in tensile and compressive strength, with values near 97–200 MPa and high stiffness, making it suitable for load‑bearing parts. UHMWPE offers exceptional impact and abrasion resistance but lower tensile strength; PTFE and PFA have lower strength but deliver low friction and good wear when filled with additives.
• Friction and self‑lubrication: PTFE is renowned for its ultra‑low coefficient of friction, providing non‑stick surfaces ideal for bearings and dynamic seals. UHMWPE is also self‑lubricating, while PFA and PEEK have moderate friction.
• Processability and cost: PFA’s molecular structure allows melt‑processing and welding, enabling complex shapes. PTFE must be compression‑molded or machined. PEEK can be machined, injection‑molded and even 3D‑printed, but its raw material cost is higher than most plastics. UHMWPE is economical and available in large sheets and rods.

These factors, along with application specifics like pressure, motion type, compliance standards and budget, guide material selection.

PTFE – benchmark for chemical resistance and low friction

PTFE is a fluoropolymer composed solely of carbon and fluorine atoms. Its molecular structure creates one of the strongest carbon–fluorine bonds in organic chemistry, giving PTFE outstanding chemical inertness. The material resists almost all chemicals, from strong acids to organic solvents, and maintains its properties across a wide temperature range with certain blends ranging from –260 °C to +315 °C. These characteristics make PTFE the gold standard for seals, linings, bearings and non‑stick surfaces.

Key properties of PTFE include:

• Low friction: PTFE’s surface has one of the lowest coefficients of friction of any solid, enabling smooth movement and reducing wear in dynamic seals.
• Exceptional chemical resistance: Virtually unaffected by acids, bases, solvents and oxidizers.
• High dielectric strength: Excellent electrical insulator for wire and cable insulation.
• Temperature stability: Continuous service temperatures from cryogenic lows up to 260 °C (500 °F) or higher for certain blends.
• Low permeability and non‑stick: Self‑lubricating surface resists fouling and buildup.

The main trade‑offs are lower mechanical strength—tensile strength is modest compared with PEEK or UHMW—and non‑melt‑processability, which limits PTFE to compression molding, machining or extrusion. PTFE is also more expensive than UHMWPE. Yet for applications requiring extreme chemical resistance and low friction, it remains indispensable. Canyon Components provides extensive PTFE solutions, from coated O‑rings and gaskets to spring‑energized seals. To learn more about PTFE’s unique attributes, see this overview of PTFE’s exceptional properties on Canyon’s website.

PFA – melt‑processable fluoropolymer with improved creep resistance

PFA (perfluoroalkoxy) shares PTFE’s fluoropolymer backbone and equally impressive chemical resistance and thermal stability, sustaining continuous service at 260 °C (500 °F). The critical difference lies in PFA’s molecular side chains. These bulky side chains enable the polymer to be melt‑processed. Melt processability allows PFA to be extruded, injection‑molded and welded, making it suitable for complex shapes such as tubing, pump housings and manifolds.

In addition to processability, PFA offers:

• Superior creep resistance at elevated temperatures: PFA maintains dimensional stability better than PTFE when under load.
• Improved flexibility and ease of fabrication: Good for components requiring forming, bending or welding.
• High purity and low contamination: Ideal for semiconductor and pharmaceutical applications.
• Comparable chemical resistance and dielectric properties to PTFE: Handles aggressive acids, bases and solvents.

PFA’s drawbacks include a higher cost and slightly higher coefficient of friction than PTFE. In sealing applications, PFA’s improved mechanical strength and processability make it an excellent choice for encapsulated O‑rings and complex seals. Canyon Components supplies encapsulated O‑rings with FEP or PFA jackets. These seals combine an elastomeric core for elasticity with a seamless PFA casing, offering chemical and thermal performance akin to PTFE but with better structural integrity. Such O‑rings are valuable in food, pharmaceutical and semiconductor systems where contamination and chemical exposure are critical concerns.

PEEK – high‑strength, high‑temperature polymer for demanding applications

PEEK (polyetheretherketone) belongs to the polyaryletherketone family of semi‑crystalline thermoplastics. Among engineering plastics, PEEK stands out for exceptional mechanical strength—tensile strength ranges from 97–200 MPa, and the elastic modulus reaches 4 GPa. PEEK retains these properties at high temperatures, with a melting point around 343 °C (649 °F) and continuous service up to about 240 °C. Unlike PTFE, PEEK can be machined, injection‑molded and 3D‑printed, and it tolerates steam sterilization and radiation, making it attractive for medical implants.

Characteristics of PEEK include:

• High strength‑to‑weight ratio: PEEK is significantly stronger than many plastics and can replace metal in some applications.
• Excellent fatigue and wear resistance: Suitable for dynamic seals, bearings and gears.
• Low moisture absorption (< 0.05 %) and good dimensional stability.
• Chemical resistance: Tolerates hydrocarbons, steam, common acids and bases.
• Radiation and sterilization resistance: Biocompatible and able to withstand gamma radiation and repeated autoclave cycles, making it ideal for medical devices.

PEEK’s disadvantages are higher cost and higher coefficient of friction compared with PTFE. Its superior mechanical properties make it ideal for parts requiring stiffness and strength—such as brackets, bearings and valves in aerospace and automotive systems—and for dynamic sealing elements like spring‑energized seals. Canyon Components manufactures custom PEEK parts through CNC machining, injection molding and additive manufacturing. Engineers can also explore Canyon’s PEEK overview to understand the material’s performance in specific industries.

UHMWPE – tough, wear‑resistant and cost‑effective

Ultra‑high molecular weight polyethylene (UHMWPE) is a polyethylene with extremely long molecular chains. This structure allows loads to be transferred effectively, giving UHMWPE outstanding impact strength, abrasion resistance and a low coefficient of friction. UHMWPE is self‑lubricating and has low moisture absorption, making it ideal for sliding surfaces, liners and wear plates.

The advantages of UHMWPE include:

• Durability: Virtually unbreakable with high impact strength.
• Abrasion and wear resistance: Maintains integrity under continuous friction.
• Low cost and ease of machining: Typically less expensive than fluoropolymers.
• Chemical resistance: Resistant to most alkalis, acids and organic solvents, though not as inert as PTFE.
• Self‑lubricating and non‑stick: Comparable to PTFE surfaces.

UHMWPE’s limitations are a lower service temperature—standard grades operate between –200 °C and 80 °C, though special grades like Polystone can melt at around 160 °C—and lower tensile strength compared with PEEK. For applications requiring exceptional wear at moderate temperatures, such as conveyor components, chute liners, gears and backup rings, UHMWPE provides a cost‑effective solution. Canyon Components offers UHMWPE as a jacket material for spring‑energized seals, where it handles reciprocating dynamic applications and slow rotary motion across –260 °C to +80 °C. The material’s low friction helps prevent stick‑slip, while its toughness resists extrusion and abrasion.

Comparative summary and selection guidelines

To illustrate the differences between these plastics, the following table summarizes key properties. Values are approximate and can vary with specific grades and fillers.

Property	PTFE	PFA	PEEK	UHMWPE
Service temperature range (°C)	–260 to +315 depending on blend	–200 to +260	–200 to +260 (continuous ~240, melt 343) depending on blend	–200 to +80 (some grades to 160 °C)
Chemical resistance	Excellent, inert to most chemicals	Excellent, similar to PTFE	Excellent to many chemicals	Good, but not suitable for strong oxidizers
Tensile strength	Low–medium; softer than PEEK	Slightly higher than PTFE	High (97–200 MPa)	Medium (impact strength high, tensile lower)
Wear and friction	Ultra‑low friction, moderate wear	Low friction, better creep resistance	Moderate friction, excellent wear with fillers	Low friction, outstanding abrasion resistance
Processability	Not melt‑processable; must be machined or molded	Melt‑processable; can be welded and molded	Machinable, moldable, 3D‑printable	Machinable; available as sheets and rods
Relative cost	Moderate–high	High	High	Low
Typical applications	Gaskets, seals, bearings, linings; electrical insulation	Tubing, manifolds, encapsulated O‑rings	Bearings, gears, valves, electrical connectors, medical implants	Wear strips, chute liners, gears, spring‑energized seal jackets

When selecting a material for sealing or custom components, consider the following guidelines:

• Extreme chemical and temperature environments: Choose PTFE or PFA. PTFE offers the lowest friction and is ideal for static and dynamic seals. PFA is preferred when parts need to be melt‑processed, welded or when slight improvements in creep resistance are valuable.
• High‑strength, high‑temperature parts: Select PEEK. Its mechanical strength and thermal stability suit load‑bearing parts and dynamic seals in aerospace, oil and gas, and medical devices.
• Cost‑sensitive applications requiring high wear resistance: Choose UHMWPE. It offers exceptional abrasion resistance and toughness at a lower cost, making it ideal for conveying and material‑handling equipment.
• Complex shapes requiring high purity: Use PFA or PEEK. PFA’s melt processability and high purity make it suitable for tubing and fluid handling in semiconductors and pharmaceuticals. PEEK can be machined into complex geometries and is available in medical grades.
• Hybrid and filled materials: Consider filled PTFE, modified PTFE, or PEEK composites when extra wear resistance, thermal conductivity or strength is needed. Canyon Components provides numerous spring‑energized seal options with filled PTFE, PEEK or UHMWPE jackets to match specific operating conditions.

Engaging an experienced partner early in the design process ensures that the selected polymer and manufacturing method align with the application’s performance requirements and budget. Canyon Components can provide custom cut gaskets and components via CNC knife, laser and waterjet cutting, in addition to advanced machining and molding services.

Conclusion

High‑performance plastics have opened new possibilities for seals and custom components that must perform reliably in extreme environments. PTFE sets the benchmark for chemical inertness and low friction; PFA offers similar resistance with melt‑processability and improved creep strength; PEEK provides unmatched mechanical strength and high‑temperature performance; and UHMWPE delivers outstanding wear and impact resistance at an economical cost. By understanding the strengths and limitations of each polymer, engineers can make informed material selections that ensure longevity and safety. Canyon Components’ extensive materials library and manufacturing capabilities empower you to turn these advanced materials into precision O‑rings, gaskets and machined parts tailored to your application. Whether you need FDA‑compliant components for pharmaceutical equipment or robust seals for downhole tools, our team can guide you to the ideal solution.