PPSU (Radel) vs PEEK
PPSU (Radel) and PEEK are both high-performance plastics used in medical and demanding applications, but they differ in structure. PPSU is amorphous, prized for outstanding impact resistance and tolerance of repeated steam/autoclave sterilization, at lower cost than PEEK. PEEK is semicrystalline, with higher temperature tolerance (~250 vs ~180 C), better wear, and stronger chemical resistance, making it the choice for the most extreme mechanical and chemical service.
The verdict
Choose PEEK for the highest temperature, wear resistance, and chemical performance in extreme mechanical and chemical environments. Choose PPSU/Radel when you need excellent impact resistance and repeated steam sterilization for surgical instruments at lower cost, where PEEK's peak temperature and wear are not required.
Side-by-side data
| Property | PPSU (Radel) | PEEK |
|---|---|---|
| Category | Engineering Plastic | Engineering Plastic |
| Density (g/cm³) | 1.29 | 1.32 |
| Tensile strength (MPa) | 70 | 100 |
| Yield strength (MPa) | 70 | 97 |
| Elongation (%) | 60 | 45 |
| Hardness | M86 | R126 |
| Max service temp (°C) | 180 | 250 |
| Machinability | ●●●●● | ●●●●● |
| Corrosion resistance | ●●●●● | ●●●●● |
| Relative cost | ●●●●● | ●●●●● |
| Thermal cond. (W/m·K) | 0.35 | 0.25 |
| Typically used for | Repeat-autoclave surgical instruments | High-temp, chemical & medical-grade parts |
Which should you choose?
Choose PPSU/Radel when…
- Repeated steam and autoclave sterilization are required — PPSU excels at hydrolytic stability
- Outstanding impact and toughness matter (elongation ~60%)
- Cost is a factor — PPSU (~4.0) is cheaper than PEEK (~5.0)
- The part is a reusable surgical instrument (its best-fit use)
- An amorphous, transparent-capable material is preferred
- Service temperature up to ~180 C is sufficient
Choose PEEK when…
- Maximum service temperature is needed (~250 C vs PPSU ~180 C)
- Wear and friction resistance drive part life in bearings and seals
- Higher strength is required (tensile ~100 vs ~70 MPa)
- The most aggressive chemical exposure must be survived
- Semicrystalline dimensional and creep stability under load matter
- The part is a demanding mechanical, chemical, or implant-grade component
Key differences that matter
- PEEK is semicrystalline with much higher service temperature (~250 vs ~180 C), better wear, and higher strength (~100 vs ~70 MPa)
- PPSU is amorphous with outstanding impact resistance and repeated steam-sterilization tolerance
- PPSU is cheaper (~4.0 vs ~5.0) — a meaningful gap in high-value medical parts
- Both rate 5/5 for chemical resistance, but PEEK resists the most aggressive media better
- PPSU's best fit is repeat-autoclave surgical instruments; PEEK's is high-temp, wear, and implant parts
- Both machine and injection mold; PPSU machines a bit easier (4.0 vs 3.0)
- PPSU offers higher impact toughness; PEEK offers higher temperature and wear life
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Open the Material SelectorGet a Quote →Frequently asked questions
Why choose PPSU over PEEK for surgical instruments?
PPSU (Radel) has outstanding impact toughness and exceptional resistance to repeated steam autoclaving without losing properties or cracking, plus it costs less than PEEK (~4.0 vs ~5.0). For reusable surgical instruments that endure hundreds of sterilization cycles and rough handling, PPSU's hydrolytic stability and toughness make it the practical, economical choice.
How much hotter can PEEK run than PPSU?
Considerably. PEEK serves to about 250 C versus PPSU's ~180 C — roughly 70 C higher. PEEK is semicrystalline, which gives it better high-temperature strength, creep resistance, and wear. For parts exposed to high continuous temperatures or hot fluids, PEEK is the appropriate material; PPSU is better suited to moderate-temperature sterilizable use.
Are both good for chemical exposure?
Yes, both are rated 5/5 for chemical resistance and tolerate a wide range of media. PEEK, being semicrystalline, generally resists the most aggressive solvents and hot chemicals better, while amorphous PPSU can be more susceptible to certain solvents. For the harshest chemical environments PEEK leads; for sterilization chemistries PPSU performs very well.
Which is tougher under impact?
PPSU. As an amorphous polymer with about 60% elongation, it absorbs impact and resists cracking exceptionally well, which is a key reason it is favored for instruments that get knocked and dropped. PEEK is tough too (~45% elongation) and far more wear-resistant, but for pure impact resistance PPSU has the edge.
Property values are typical/nominal figures for early-stage guidance only and vary by temper, grade, supplier and heat treatment. Confirm critical specifications against a certified datasheet or with an mfgiq engineer before production.