Ultem PEI Grades — 1000 vs 2300 vs 2200 vs CF

Ultem (polyetherimide) is produced by SABIC in several distinct formulations. Each grade shares the same imide-ether polymer backbone—and therefore the same inherent UL94 V-0 rating, FAR 25.853 flammability compliance, and autoclave stability—but differs in mechanical properties based on reinforcement type and loading. Selecting the wrong grade costs dimensional stability, machinability, or strength. This page defines each grade's property profile, intended application space, and availability in stock shapes.

At a glance:

• Ultem 1000: unfilled, transparent amber, general-purpose—the baseline for medical, electrical, and prototype work
• Ultem 2200: 20% glass fiber, improved stiffness, moderate machinability trade-off
• Ultem 2300: 30% glass fiber, highest stiffness and tensile in the family, used in structural aerospace parts
• Ultem CF: carbon-fiber filled, adds EMI shielding and ESD dissipation
• All grades: inherent V-0, FAR 25.853-compliant, autoclavable to 270°F steam
• Glass-filled grades are opaque; unfilled 1000 is transparent amber

Grade Comparison Table

Ultem 1000 — Unfilled Baseline

Ultem 1000 is the standard unfilled grade and the most widely stocked form in plastic distribution. Its transparent amber color allows visual inspection of part cross-sections, a useful feature when machining complex geometries and during quality inspection. With a tensile strength of 15,000 psi and elongation at break around 60%, it is the most impact-tolerant grade in the family—though still brittle by engineering thermoplastic standards compared to polycarbonate or nylon.

When to specify Ultem 1000

• Medical sterilization trays and fixtures requiring FDA 21 CFR compliance and visual inspection capability
• Electrical connector housings and insulating standoffs where transparency aids assembly verification
• Prototype and development parts where grade-specific qualification is not yet established
• Applications where snap-fit or modest deflection is required—the higher elongation is the only option in the family

Ultem 1000 machines the most cleanly. Surface finishes of 32 µin Ra or better are achievable with proper cutting technique. See the Ultem machining guide for feeds and speeds.

Ultem 2200 — 20% Glass Fiber

Ultem 2200 (also designated GF20) adds 20% by weight short glass-fiber reinforcement to the Ultem 1000 base resin. This intermediate glass loading bridges the gap between the unfilled grade's impact tolerance and the Ultem 2300's maximum stiffness.

Property gains over Ultem 1000

Tensile strength rises to approximately 20,000 psi and flexural modulus to roughly 850,000 psi. CLTE drops from 31 to approximately 20 × 10⁻⁶ in/in/°F, improving dimensional stability in thermal cycling applications. The lower glass content compared to 2300 reduces machining abrasiveness somewhat, making 2200 a practical compromise when neither the full stiffness of 2300 nor the ease of machining of 1000 is the primary concern.

When to specify Ultem 2200

• Structural brackets and housings requiring more stiffness than unfilled Ultem but where the full glass loading of 2300 is excessive
• Applications with moderate thermal cycling where CLTE reduction improves fit with metal mating parts
• Situations where machining volume is high and tool costs from abrasive 2300 are a concern

Stocking of 2200 in rod and sheet is less universal than 1000 or 2300; confirm availability and lead time with your distributor before designing around this grade.

Ultem 2300 — 30% Glass Fiber

Ultem 2300 is the stiffest and strongest standard grade in the family. At 25,000 psi tensile strength and 1,200,000 psi flexural modulus, it overlaps with the lower end of aluminum structural performance on a unit-area basis and significantly exceeds the unfilled grade at elevated temperature.

Key advantages

The reduced CLTE (14 × 10⁻⁶ in/in/°F) is the primary structural advantage in multi-material assemblies subject to thermal cycling. An Ultem 2300 bracket assembled to an aluminum airframe sees far less differential expansion than one made from unfilled Ultem 1000. The 30% glass loading also improves creep resistance at temperature.

Trade-offs

Elongation at break drops to ~3%—Ultem 2300 is brittle. Press-fit assemblies and snap-fit features are not appropriate. Machining tool wear increases; use carbide tooling exclusively. Glass fibers introduce surface texture that must be managed on sealing surfaces and precision-fit interfaces.

When to specify Ultem 2300

• Aerospace structural members: seat frames, overhead bin structural brackets, airframe secondary brackets
• High-load bearing surfaces operating above 250°F
• Metal-replacement designs where thermal expansion matching to aluminum is a design requirement
• Parts requiring maximum stiffness for vibration control

Ultem CF — Carbon-Fiber Filled

Carbon-fiber-filled Ultem replaces glass reinforcement with short carbon fibers, typically at 10–20% loading depending on the formulation. The property profile is broadly similar to Ultem 2300 in stiffness (flexural modulus ~1,100,000 psi) but with several important differences:

Electrical conductivity. Carbon fiber makes the grade electrically conductive at the surface and through the thickness. Surface resistivity drops to the 10³–10⁵ Ω range—ESD dissipative territory. This is critical for semiconductor wafer carrier and electronic test fixture applications where electrostatic discharge can damage devices. The carbon content also provides EMI shielding at higher loadings.

Lower density. Carbon fiber is less dense than glass fiber, so CF-filled Ultem is somewhat lighter than GF30 at comparable stiffness—a small but real advantage in weight-critical aerospace applications.

Higher CLTE anisotropy. Carbon fiber reinforcement creates stronger property directionality (anisotropy) in machined shapes than glass, depending on fiber orientation in the stock. For precision parts, verify CTE values in both X and Y orientations relative to the extrusion or pressing direction of your stock.

Opaque black color. Carbon fiber content produces a matte black part that is also somewhat abrasive to tooling.

When to specify Ultem CF

• Semiconductor wafer cassettes, end-effectors, and fixtures requiring ESD dissipation
• Electronics test sockets and burn-in boards where static buildup is unacceptable
• Weight-critical structural components where the slightly lower density matters

Grade Selection Summary

For full dimensional availability by grade, see the specifications page. For head-to-head comparison with PEEK grades, see Ultem vs PEEK.

More related guides

Cross-cluster suggestions to help shoppers and engineers explore adjacent topics:

Applications

• Gears
• Electrical Insulation
• Aerospace Interior

Industries

• Aerospace
• Medical

Compare to other materials

• Peek Vs. Ultem Pei
• Ultem Vs. Polycarbonate
• Ultem Vs. Polysulfone

Frequently asked questions — Ultem Pei FAQ