# PEI

Polyetherimide selection by grade, supplied form, thermal rating and manufacturing history.

Reviewed: 2026-11-01

Tags: materials, polymers, thermoplastics

## Identity and grade boundaries

MCAM's **Duratron U1000 PEI** gives **195°C HDT** under **ISO 75 method A at 1.8 MPa**, and separately lists **170°C continuous temperature in air**. The air-aging criterion concerns **about 50% tensile-strength loss after at least 20,000 h**, measured at **23°C**. Evaluate sustained stress and exposure separately for a loaded assembly. [MCAM Duratron U1000 footnotes](https://www.mcam.com/mam/datasheets/AEP-Duratron%C2%AE%20U1000%20PEI_en_US.pdf)

PEI means **polyetherimide**, an amorphous engineering thermoplastic. It is a material family rather than a complete purchase specification. SABIC's ULTEM portfolio includes unreinforced and reinforced resins, flow variants and specialty formulations. Its portfolio guide, carrying a **2023 copyright**, separately describes chemically resistant CRS grades and more flexible SILTEM materials; those benefits cannot be assigned to every product bearing a related trade name. Specify the exact manufacturer and grade before selecting properties. [SABIC: ULTEM portfolio guide](https://www.sabic.com/en/Images/ULTEM-resin-PEI-polyetherimide-high-heat-product-portfolio_tcm1010-42565.pdf)

Separate resin pellets, extruded or otherwise produced stock shapes, molded parts and additively manufactured parts in a material record. Each route needs its own property evidence and process controls. For example, MCAM identifies Duratron U1000 as amorphous PEI stock shapes available as rod and plate; regional sizes and colors can differ. That identifies a machinable product, not a guarantee that a molded or printed ULTEM component has identical performance. [MCAM: Duratron U1000 product page](https://www.mcam.com/en/products/shapes/advanced/duratron-pei/duratron-u1000-pei)

## Temperature ratings describe different tests

MCAM's Duratron U1000 datasheet, revised **7 March 2023**, provides a useful bounded example:

| Quantity | Listed value and basis |
| --- | --- |
| Glass transition | 215 °C, DMA tan δ |
| Heat-deflection temperature | 195 °C, ISO 75-1/-2, method A, 1.8 MPa |
| Continuous allowable temperature in air | 170 °C, with the sheet's 20,000-hour criterion |

The long-term criterion concerns approximately 50% tensile-strength loss after at least 20,000 hours, measured at 23 °C. The footnote also makes allowable service temperature dependent on stress and duration. These values describe different phenomena; none establishes the operating temperature of a loaded assembly. The sheet calls its dry-material values indicative, nonguaranteed and insufficient alone for design or specification limits. [MCAM: U1000 datasheet and footnotes](https://www.mcam.com/mam/datasheets/AEP-Duratron%C2%AE%20U1000%20PEI_en_US.pdf)

A glass transition is not a processing setpoint or a safe excursion limit. Define requirements through load, time, deformation, thermal cycling and surrounding medium; a short-term deflection test does not qualify years of creep.

## Reinforcement and directional expansion

SABIC's automotive-sensor brochure, carrying a **2022 copyright**, identifies ULTEM 2300 as a standard-flow **30% glass-fiber-reinforced PEI** and ULTEM 2310 as an improved-flow alternative. Its comparison table lists ULTEM 2300 thermal-expansion coefficients of **1.8 × 10⁻⁵/°C in flow** and **4.8 × 10⁻⁵/°C across flow**. Preserve direction when transferring such data to a drawing or simulation. The brochure is an application comparison, so obtain the current grade datasheet and complete test conditions before treating its figures as design inputs. [SABIC: ULTEM 2300/2310 automotive sensors](https://www.sabic.com/en/Images/SABIC-PLA-25210-Ultem-2300-Automotive-sensors_tcm1010-38514.pdf)

**Illustrative calculation:** assuming those coefficients apply uniformly over a 50 °C rise, a free 100 mm length would expand by 0.09 mm in flow or 0.24 mm across flow: ΔL = αLΔT. These calculated values illustrate anisotropy only. They do not predict a constrained molded housing, weld line, fiber-orientation pattern or metal insert stress.

For a tight fit, record the relevant direction, temperature interval, conditioning and manufacturing route. Compare the assembled dimensions at the intended operating conditions; a single room-temperature modulus or expansion coefficient cannot settle the fit.

## Moisture, fluids and cleaning

Chemical resistance needs an exposure description. SABIC's thermal-management application sheet presents property-retention comparisons after **3,000 hours at 130 °C in glycol/water** and **2,000 hours at −40 °C in R1234yf refrigerant**. The accessible sheet does not identify a complete grade-and-test protocol for turning those comparisons into a general allowable. Use it as evidence of investigated applications, then request the exact formulation, fluid composition, specimen condition, stress and acceptance criterion for the intended part. Do not extrapolate it to every coolant, solvent or cleaning cycle. [SABIC: thermal-management exposure comparisons](https://www.sabic.com/en/Images/EV-thermal-management-applications-with-SABIC-ULTEM-resin_tcm1010-41317.pdf)

For qualification, distinguish immersion from wiping, intermittent splashes and vapor exposure. Include moisture conditioning and drying between cycles where relevant. Inspect dimensions and surface cracking as well as retained strength; a functional seal or transparent cover may fail its requirement without a large change in a tensile coupon result.

## Manufacturing and joining controls

For molding or extrusion, obtain the specific resin's drying, moisture, melt-temperature, residence-time and tooling recommendations. Keep those instructions separate from stock-shape annealing and finished-part service limits. Record regrind or recycled-content restrictions, color formulation and any change in source material before approving a substitution.

MCAM's machining guidance warns that mineral-oil-based cutting fluids can contribute to stress cracking in amorphous products including Duratron U1000 PEI. It also explains that stock shapes receive a proprietary stress-relief cycle, while substantial machining can justify further stress relief. Select tooling, cooling, clamping and any intermediate anneal for the actual grade and geometry. A generic metalworking coolant or an arbitrary oven cycle is not a qualified PEI process. [MCAM: machining toolkit](https://www.mcam.com/mam/41701/MCG-Machinist-Toolkit-A4-EU-metric.pdf)

Bonding also needs local validation. Ensinger lists PEI among amorphous plastics that can be comparatively easy to bond because of partial dissolvability, while warning about stress cracking. Its guidance calls for adhesive selection against mechanical, thermal and chemical requirements, appropriate pretreatment and tests for the actual project. Qualify the cleaner, adhesive and cure cycle together, including residual assembly stress. [Ensinger: bonding high-performance plastics](https://www.ensingerplastics.com/en-us/plastic-material-selection/easy-to-bond)

## Handling and acceptance record

MCAM's U1000 handling sheet is dated **28 July 2022, version 2.0**. It treats its stock shapes and machined products as REACH articles, recommends indoor storage away from degradation sources, and warns that dimensional changes can occur with time. During machining it calls for swarf removal, eye protection and observance of applicable workplace dust limits. This document concerns that supplied product; obtain the relevant safety information for pellets, processing additives, adhesives and other materials used alongside it. [MCAM: U1000 product handling information](https://www.mcam.com/mam/34157/MCAM-Duratron_U1000_PEI-EN-PHS-220812.pdf)

A useful purchase and qualification record includes:

- Exact grade, supplier, color, reinforcement and supplied form.
- Source revision, specimen preparation, conditioning and test method.
- Manufacturing route and controls for machining, molding or printing.
- Load duration, thermal cycle, fluids and cleaning sequence.
- Finished-part tolerances, measurement condition and acceptance tests.
- Any required electrical, flame, food-contact or medical documentation for the exact product and intended use.

## Related reference

[Material selection through production](../grades-tempers-and-conditions.md)