Ultra-High Performance
Polymer Selection Guide
Compare PI, PAI, PEEK, and PEI materials for high-temperature and high-load engineering applications.
01
FILTER 1
Determine Operating Temperature
If your continuous service temperature exceeds 250°C - 300°C+, focus on PI or PAI. For applications below 240°C, PEEK offers the most cost-effective performance.
02
FILTER 2
Analyze Friction & Mechanical Load
Under heavy mechanical loads or high-velocity friction (without lubrication), PAI (Torlon) provides unmatched wear life. For standard high-strength structural parts, PEEK or PEI is preferred.
03
FILTER 3
Check Chemical Exposure & Environment
If the environment involves aggressive acids, alkalis, or steam, PEEK offers nearly universal resistance. For semiconductor plasma environments or high dielectric insulation needs, evaluate PI or PEI.
04
FINAL MATCH
Get Technical Data Sheets (TDS)
Based on your criteria, match the exact grade. If you need standard profiles (rods/sheets) or precision machined parts, our engineers are ready to cross-reference your blueprints.
PI
The king of heat resistance and electrical insulation. Widely used for films and precision bearings.
PAI
Unmatched in mechanical strength, wear resistance, and high-temperature rigidity. The top choice for high-load bearings and seals.
PEEK
Offers the best balance of chemical resistance, self-lubrication, and semi-crystalline stability. A classic choice for Oil & Gas and medical implants.
PEI
The leader in cost-effectiveness, transparency, and processability. A mainstay for high-end applications in aerospace and electronics.
Basic Definitions & Structural Comparison
| Property | PI (Polyimide) | PAI (Polyamide-imide) | PEEK (Polyetheretherketone) | PEI (Polyetherimide) |
|---|---|---|---|---|
| Crystallinity | Semi-crystalline / Amorphous (Grade dependent) | Amorphous | Semi-crystalline | Amorphous |
| Appearance | Dark Brown / Black (Opaque) | Amber / Black (Translucent) | Beige / Black (Opaque) | Transparent Amber / Black (High Transparency) |
| Typical Tg / Tm | Tg >300°C / Decomposes ~500°C | Tg 275°C / No distinct Tm | Tg 143°C / Tm 343°C | Tg 217°C / No Tm |
| Processing Trend | Thermoset-like (Requires post-curing) | Melt-processable (Requires post-curing) | Typical Thermoplastic | Typical Thermoplastic |
Performance Characteristics Comparison
| Property | PI | PAI | PEEK | PEI | Ranking (High to Low) |
|---|---|---|---|---|---|
| Continuous Service Temp | 260-300°C+ (Short 500°C) | 260°C | 250°C (Short 300°C) | 170-180°C (Short 210°C) | PI > PAI > PEEK > PEI |
| HDT (1.8MPa) | 300°C+ (Higher if filled) | 270-280°C | 250-320°C (Filled) | 190-210°C | PI > PAI > PEEK > PEI |
| Tensile Strength (MPa) | 80-120 | 190-220 (Highest) | 90-110 | 100-120 | PAI >> PEI ≈ PI > PEEK |
| Notched Impact Strength | Med - High | High (Great Toughness) | Med - High | High (Excellent) | PAI ≈ PEI > PEEK ≈ PI |
| Compressive Strength / Rigidity | Extremely High | Highest (2x PEEK) | High | High | PAI > PI > PEEK ≈ PEI |
| Chemical Resistance | Excellent | Excellent | Extreme (Conc. H₂SO₄ only) | Good - Excellent | PEEK > PAI ≈ PI > PEI |
| Wear / Friction Coeff. | Excl. (Best at high temp) | V. Good (Lowest if modified) | V. Good (Bearing King) | Average | PAI ≈ PEEK > PI > PEI |
| Dimensional Stability / Creep | Excellent | Excellent | Excellent | Excellent | PI > PAI ≈ PEEK ≈ PEI |
| Transparency / Processing | Fair (Film only) / Difficult | Translucent / Med (Post-cure) | Opaque / Good | High Transp / Best (Easy IM) | PEI > PEEK > PAI > PI |
| Flame Retardancy | V-0 Inherent | V-0 Inherent | V-0 Inherent | V-0 Inherent | All Equivalent |
Application Scenario Comparison
| Material | Core Advantages | Typical Applications | Market Positioning |
|---|---|---|---|
| PI | Ultimate heat resistance, electrical insulation, and aerospace extremes. | Aero-engine insulators, Kapton flexible circuits, semiconductor wafer rings, high-precision bearings, rocket nozzles. | Premier choice for Aerospace, Semiconductor, and High-temp Films. |
| PAI | Superior strength, high-temp wear resistance, and reliable sealing. | Aerospace hydraulic pumps, automotive turbo impellers, oil-drilling seals, bearing cages, medical instruments. | High-end Aerospace, Oil & Gas, and Precision Bearings. |
| PEEK | Optimal chemical resistance, self-lubrication, and biocompatibility. | Oil & Gas valves, medical implants/screws, semiconductor wafer carriers, automotive gears, food processing parts. | Mainstream leader for Oil & Gas, Medical, and Automotive. |
| PEI | Cost-effective, transparent, easy processing, and aerospace certified. | Aircraft interior panels, medical instrument handles, electronic connectors, LED reflectors, water filtration supports. | High-to-Mid-end Aerospace, Electronics, and Medical. |
Quick Material Selection Decision Form
(One-Sentence Summary)
| Your Core Requirement | Top Choice | Quick Reason |
|---|---|---|
| Highest Heat + Electrical Insulation + Film/Aerospace | PI | "The Heat Ceiling" – Exceptional performance, though hardest to process. |
| Max Mechanical Strength + High-temp Wear + Sealing | PAI | "King of Strength & Wear" – The classic Torlon® standard. |
| Best Chemical Resistance + Self-lubrication + Bio-compat | PEEK | "The All-Rounder" – Top pick for Oil & Gas and Medical implants. |
| Cost-effective + High Transp + Easy IM + Aero-Certified | PEI | "The Smart Choice" – The Ultem® value-performance king. |
| Limited Budget but Needs 180°C+ Heat Resistance | PEI | Most affordable high-performance polymer option. |
| Needs Ultimate Strength or High-temp Bearings | PAI / PI | PAI for easier machining; PI for extreme environments. |
Related Material Comparisons
- PI vs PAI vs PEEK vs PEI
- PEEK vs PTFE
- PEEK vs Metal
- PEEK vs PEI
FAQ
What is the best high-temperature engineering plastic?
There is no single "best" plastic, as the choice depends on your specific application requirements. However, PEEK (Polyetheretherketone) and PI (Polyimide) are the top choices for extreme heat.
PEEK offers an excellent balance of continuous service temperature (up to 250°C/482°F), high mechanical strength, and superb chemical resistance.
For even higher thermal stability, PI (Polyimide) can withstand continuous temperatures exceeding 300°C (572°F) and up to 500°C for short periods, making it ideal for the most demanding aerospace and semiconductor environments.
PEEK offers an excellent balance of continuous service temperature (up to 250°C/482°F), high mechanical strength, and superb chemical resistance.
For even higher thermal stability, PI (Polyimide) can withstand continuous temperatures exceeding 300°C (572°F) and up to 500°C for short periods, making it ideal for the most demanding aerospace and semiconductor environments.
Which material is better for semiconductor applications?
Both PEEK and PPS (Polyphenylene Sulfide) are widely used in semiconductor manufacturing, but they serve different needs:
PEEK is preferred for critical, high-stress components (such as wafer carriers, CMP rings, and test sockets) due to its superior wear resistance, extremely low outgassing, and high purity.
PPS is an excellent, cost-effective alternative for structural parts and wet-bench components where high chemical resistance to aggressive cleaning agents is required, but mechanical stress and temperatures are slightly lower.
For static-sensitive environments, ESD-safe grades of PEEK or POM are highly recommended.
PEEK is preferred for critical, high-stress components (such as wafer carriers, CMP rings, and test sockets) due to its superior wear resistance, extremely low outgassing, and high purity.
PPS is an excellent, cost-effective alternative for structural parts and wet-bench components where high chemical resistance to aggressive cleaning agents is required, but mechanical stress and temperatures are slightly lower.
For static-sensitive environments, ESD-safe grades of PEEK or POM are highly recommended.
Is PEEK stronger than PEI?
Yes, PEEK is generally stronger and more durable than PEI (Ultem). While both are high-performance amorphous/semi-crystalline polymers, PEEK delivers significantly higher tensile strength, better fatigue resistance, and superior impact toughness. Additionally, PEEK offers much better wear and friction performance. However, PEI is an excellent choice if you need a more cost-effective solution with high dielectric strength and inherent flame resistance, especially for electrical or structural parts that don't require PEEK's extreme chemical or wear resistance.
How do I choose between PTFE and PEEK for sealing applications?
The choice between PTFE and PEEK comes down to a trade-off between flexibility/friction and load-bearing capacity:
PTFE (Teflon) is ideal for low-friction, high-chemical-purity seals at moderate pressures. It has near-universal chemical resistance and operates smoothly, but it is prone to "creep" (deformation under load).
PEEK should be selected when the seal or backup ring must withstand extremely high pressures, loads, and wear without deforming. PEEK is rigid, whereas PTFE is soft and compliant.
When should I choose POM (Acetal) instead of high-performance plastics like PEEK?
POM is the ultimate "value engineering" choice for mechanical precision parts. If your operating temperature stays below 100°C (212°F) and the chemical environment is moderate, POM offers outstanding dimensional stability, low friction, and high stiffness at a fraction of the cost of PEEK. Switch to PEEK only when POM fails to meet the thermal, chemical, or extreme mechanical load requirements of your application.
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