High-Performance Polymers
PEEK, PPS, PEI, PTFE, Ultem and reinforced grades for demanding duty
High-performance polymers retain mechanical properties and dimensional stability where commodity plastics fail: continuous service above 150 °C, aggressive chemicals, radiation, wear and friction. The shortlist for machined and molded parts is PEEK, PPS, PEI (Ultem), PTFE, PI and PAI (Vespel), each with a distinct cost/performance profile — typically 10–100× the price of ABS.
1. The material shortlist
PEEK (polyether ether ketone) is the benchmark: UTS ≈97 MPa (unfilled), continuous use to ~250 °C, chemical resistance across almost all solvents, and excellent creep resistance; glass- or carbon-reinforced grades raise modulus and reduce wear. PPS (polyphenylene sulfide) offers similar temperature performance at lower cost with outstanding chemical resistance but is more brittle.
PEI (polyetherimide, Ultem) is an amorphous high-temperature polymer with UTS ≈105 MPa, good electricals and flame resistance. PTFE (Teflon) is the extreme low-friction, chemically inert material (use to ~260 °C) but is soft and creeps — often used as a liner or in compounds.
2. Machining considerations
High-performance polymers machine like engineering plastics but demand sharp tools and controlled heat: PEEK and PEI can be machined to ±0.05 mm with good finish; PTFE is gummy — sharp rakes, high speed and coolant are essential to avoid smearing and tool loading.
Anisotropy from processing (extruded rod vs molded) affects warpage and mechanical consistency; for precision parts, machine from stress-relieved or annealed stock and allow stabilization before final dimensions.
3. Applications and trade-offs
PEEK replaces metal in aerospace brackets, medical implants and semiconductor hardware where weight, corrosion and sterilization matter. PPS suits automotive and fuel-system components; PEI serves electrical connectors and aircraft interiors; PTFE seals, bearings and chemical liners; PAI (Vespel) for extreme wear at temperature.
The trade is cost and processability: PEEK costs roughly 30–60× ABS per kilogram; PTFE is cheap by comparison but dimensionally unstable. Each also has a weakness — PTFE creeps, PPS is brittle in thin sections, PEI stress-cracks in some solvents, PEEK is expensive and needs high molding temperatures.
4. Selection guidance
Choose the lowest-cost polymer that meets the peak service temperature, chemical exposure and wear duty. If the application only needs 100 °C and mild chemicals, PA66 or POM will outperform a high-performance polymer on cost and machinability.
When quoting, high-performance polymers are priced by material weight plus a machining/molding surcharge; small quantities are expensive because material minimums dominate. Get the datasheet of the specific grade (e.g. PEEK 450G vs GF30) before finalizing the design.
Quick reference
| Material | Density g/cm³ | UTS MPa | Max continuous °C | Cost index (ABS=1) | Key trait |
|---|---|---|---|---|---|
| PEEK 450G | 1.30 | 97 | 250 | 30–60 | Best all-round high-temp |
| PEEK GF30 | 1.49 | 165 | 250 | 35–65 | Stiff, low creep |
| PPS | 1.35 | 90 | 200 | 10–20 | Chemicals, low cost |
| PEI (Ultem) | 1.27 | 105 | 170 | 8–15 | Electrical, flame |
| PTFE | 2.20 | 27 | 260 | 3–8 | Friction, inert, soft |
| PAI (Vespel) | 1.45 | 130 | 275 | 60–100 | Extreme wear |
Sources & references
- ASTM D638 — Tensile
- ASTM D3418 — Transition temperatures
- ISO 527 — Tensile properties of plastics
- Xometry Learning Center — High-Performance Polymers Guide (public engineering reference)