Ultem 2300: Properties, Uses & Cost Guide
Tensile data verified against MatWeb.com database & manufacturer datasheets · Last updated July 2026
Published: 2026-05-31
Ultem 2300 is the 30% glass-fiber-reinforced grade of polyetherimide (PEI), engineered to provide dramatically higher stiffness, lower thermal expansion, and improved dimensional stability compared to unfilled Ultem 1000. The glass fiber...
Ultem 2300 is the 30% glass-fiber-reinforced grade of polyetherimide (PEI), engineered to provide dramatically higher stiffness, lower thermal expansion, and improved dimensional stability compared to unfilled Ultem 1000. The glass fiber reinforcement increases flexural modulus by ~2.7× (9.0 GPa vs 3.3 GPa unfilled) and reduces mold shrinkage to 0.2-0.4% (vs 0.5-0.7% unfilled) — critical for tight-tolerance electrical connectors, circuit breaker housings, and avionics enclosures where post-molding warpage would cause misalignment.
Ultem 2300 is the dominant material for high-temperature electrical connectors and sockets in aerospace, military, and downhole oil-and-gas applications. It is inherently flame-retardant (UL 94 V-0 at 0.25 mm without flame-retardant additives — the polymer backbone contains aromatic imide groups that char rather than burn), has excellent dielectric properties stable across a wide frequency and temperature range, and withstands lead-free (RoHS) soldering processes (peak reflow temperatures 260°C for 30 seconds) that would melt or distort standard engineering thermoplastics (PBT, PA66, POM).
Processing requires high mold temperatures (135-165°C, oil-heated) and melt temperatures of 370-400°C. Drying is ESSENTIAL: PEI absorbs moisture rapidly from ambient air; processing undried PEI at 370°C causes hydrolysis (polymer chain scission) resulting in a 30-50% loss of tensile strength and elongation — parts shatter under load. Dry at 150°C for minimum 4 hours (desiccant dryer, -40°C dew point) to <0.02% moisture content.
Recommended Applications
Ultem 2300 is commonly specified for:
⚠ Not Recommended For
Ultem 2300 is not recommended for:
- Strong alkali environments (NaOH, KOH — PEI degrades; use PPS or PEEK for alkaline service)
- Continuous steam exposure above 180°C (use PEEK or PAI for extreme autoclave)
- Food contact without specific FDA-compliant grade certification
Selection & Application Guide
Ultem (PEI) provides the best balance of high-temperature performance, processability, and cost among amorphous high-temperature thermoplastics. Choose Ultem when continuous service temperature up to 170°C is needed with good strength, inherent flame resistance (UL94 V-0), and transparency options. Ultem is easier to process than PEEK or Torlon and costs 60-70% less, making it the pragmatic choice when PEEK-level temperature resistance isn't required.
Real-World Applications
Ultem meets FAA flammability, smoke, and toxicity (FST) requirements for aircraft interior trim, tray tables, and ventilation ducts — replacing aluminum at 40% weight savings.
Ultem's autoclave resistance (134°C steam sterilization), rigidity, and ability to be gamma-sterilized make it standard for reusable surgical tool handles and dental instrument bodies.
Ultem's high dielectric strength, low dissipation factor, and UL94 V-0 rating without flame retardant additives make it the go-to material for high-performance electrical connectors.
Ultem's heat resistance to halogen bulb temperatures, dimensional stability, and metallization capability suit it for headlamp reflectors and fog light housings.
Processing & Cost Considerations
Manufacturing Tips
- Ultem processes at melt temperatures of 340-425°C with mold temperatures of 130-180°C — high but achievable on many standard machines with high-temperature upgrades. No post-curing is required, unlike Torlon.
- Ultem is hygroscopic and must be dried at 150°C for 4-6 hours before processing. Moisture content above 0.05% causes splay marks and reduced mechanical properties. Use a dehumidifying dryer for consistent results.
- Glass-filled Ultem (2300, 30% GF) provides 2× the stiffness and HDT of unfilled grade, but at the cost of reduced impact strength and isotropic properties. Gate design must account for fiber orientation in glass-filled grades.
Ultem costs $30-80/kg — significantly less than PEEK ($80-200/kg) and Torlon ($80-120/kg). This cost advantage, combined with easier processing (no post-cure, lower mold temperatures), makes Ultem the economical high-temperature polymer choice for most applications below 170°C. Glass-filled Ultem 2300 is 10-15% more expensive than unfilled but often eliminates the need for a more expensive polymer like PEEK.
Technical Properties
| Density | 1.51 g/cm³ |
|---|---|
| Tensile Strength | 170 MPa |
| Melting Point | N/A (Amorphous, Tg 217 °C) |
| Shrinkage Rate | 0.4% |
| Flexural Modulus | 9.0 GPa |
| Hdt | 212 °C at 1.82 MPa |
| Continuous Service Temp | 170 °C |
Engineering Tool: Shrinkage & Cost Estimator
Calculate part weight, mold cavity dimensions accounting for shrinkage, and material cost — all locally in your browser.
Equivalents & Cross-References
| Equivalent / Alternate | Action |
|---|---|
| Sabic Ultem 2300 | |
| GEHR PEI-GF30 | |
| Ensinger TECAPEI GF30 |
Frequently Asked Questions
Can Ultem replace PEEK in my application?
It depends on your temperature requirement. Ultem's continuous service temperature is 170°C vs PEEK's 260°C. If your application stays below 170°C and doesn't require PEEK's chemical resistance to aggressive solvents, Ultem provides comparable strength at roughly half the material cost with easier processing. Above 170°C, PEEK is necessary.
Is Ultem transparent?
Unfilled Ultem is amber-transparent — it transmits light with an amber tint, not water-clear like polycarbonate or acrylic. This makes it suitable for light pipes and indicators where color is acceptable. For water-clear transparency, consider polysulfone (PSU) or optical PC instead.
Can Ultem be sterilized?
Yes. Ultem withstands all common sterilization methods: steam autoclave (134°C, 18 minutes), ethylene oxide gas, gamma radiation, and dry heat. It maintains mechanical properties through hundreds of autoclave cycles, making it ideal for reusable medical devices.
What is the difference between Ultem 1000 and Ultem 2300?
Ultem 1000 is the unfilled general-purpose grade with 105 MPa tensile strength and 217°C HDT. Ultem 2300 is 30% glass-filled with 186 MPa tensile strength and 210°C HDT at 1.82 MPa. The glass-filled grade provides much higher stiffness but lower impact resistance and is opaque amber rather than translucent.
Does Ultem require flame retardant additives?
No. Ultem achieves UL94 V-0 rating inherently at 0.41mm thickness without any flame retardant additives. This is a major advantage over polycarbonate (which requires brominated additives for V-0) for aircraft interior and electrical applications where halogen-free flame resistance is specified.
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References & Industry Standards
- ASTM International. Standard Specifications for Engineering Plastics & Thermoplastics. astm.org
- UL Prospector. Plastics & Elastomers Material Database. ulprospector.com
- MatWeb. Material Property Data for Engineering Thermoplastics. matweb.com
- ISO 1043. Plastics — Symbols and Abbreviated Terms. iso.org